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In This Report

•	Highlights
•	Introduction
•	Diagnosis
•	Complications
•	Risk Factors
•	Prevention
•	Treatment
•	Medications
•	Resources
•	References

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•	Allergic Rhinitis (Hay Feve...
•	Immunizations

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Colds and the Flu

Highlights

Antiviral Drugs for Influenza

The U.S. Centers for Disease Control has recommended that neither amantadine nor rimantadine should be used to treat influenza (flu) during the 2005- 2006 flu season. A high proportion of influenza A strains have become resistant to these drugs.

Oseltamivir (Tamiflu) or zanamivir (Relenza) may be used to prevent or treat complications of the flu. These should not be used for routine treatment of seasonal flu, however. According to an article published in January 2006 in the Lancet, these should be used only during a serious epidemic or pandemic, and in conjunction with public health measures such as quarantine and rigorous hygiene practices.  

Each of the influenza drugs can prevent or reduce symptoms of the flu caused by drug-sensitive strains of the virus. Although amantadine and rimantadine have been very helpful in previous years, drug resistant strains have increased sharply this year. Tamiflu and Relenza remain active against current human influenza virus.

Relenza and Tamiflu reduce “viral shedding,” or transmission of the flu virus from the nose, although they do not stop viral shedding completely. Amantadine and rimantadine do not reduce viral shedding. Moreover, they encourage flu strains to develop resistance.

New Test for Avian Flu

In February 2006, the U.S. Food & Drug Administration approved a new, faster test for diagnosing strains of avian influenza (bird flu) in people suspected of having the virus. The test is called the Influenza A/H5 (Asian lineage) Virus Real-time RT-PCR Primer and Probe Set. The test gives preliminary results within 4 hours. Older tests required 2 to 3 days. At the time of this publication, at least 165 people have been infected with the avian (H5N1) flu in 6 countries. More than half have died. No cases have been seen in the United States. The avian flu virus has spread from birds to people. 

Seasonal Flu Vaccine

The Advisory Committee on Immunization Practices (ACIP) recommends that several additional adult populations receive influenza (flu) vaccinations, including:

• All healthcare workers
• Patients with any condition that affects breathing
• Patients with any condition that produces respiratory secretions (for example, mucus from a runny nose or cough)
• People who live with those who are at high risk of flu complications

The CDC recommends that children under 9 years of age receive two doses of the flu vaccine one month apart, because they do not develop a strong immune response from a single dose.

Introduction

Upper respiratory tract infections affect the airways in the nose, ears, and throat.

Structures of the throat include the esophagus, trachea, epiglottis and tonsils.

The infections can be caused by viruses, bacteria, or other microscopic organisms. In most cases, these infections lead to colds or mild influenza (flu) and are temporary and harmless. In rare cases, flu can be severe, or the infections may turn into pneumonia.

Organisms that cause these upper respiratory tract infections are generally spread by:

• Direct contact (such as hand-to-mouth)
• Coughing or sneezing

The Common Cold

The common cold (medically known as infectious nasopharyngitis) is the most common upper respiratory tract infection. More than 200 viruses can cause colds. The most common cause is the rhinovirus, which is responsible for about half of all colds. Symptoms usually develop one to three days after being exposed to the virus.

A cold usually progresses in the following manner:

• It nearly always starts rapidly with throat irritation and stuffiness in the nose.
• Within hours, full-blown cold symptoms usually develop, which can include sneezing, mild sore throat, fever, minor headaches, muscle aches, and coughing.
• Fever is low-grade or absent. In small children, however, fever may be as high as 103 degrees F for one or two days; it should go down after that and be normal by the fifth day.
• Nasal discharge is usually clear and runny the first one to three days. It then thickens and becomes yellow to greenish.
• The sore throat is usually mild and lasts only about a day. A runny nose usually lasts two to seven days, although coughing and nasal discharge can persist for more than two weeks.

Influenza (The "Flu")

Symptoms.  Patients usually feel sick 1 to 4 days after exposure to the influenza (flu) virus. The flu usually involves:

• Abrupt onset of severe symptoms, which include headache, muscle aches, fatigue, and high fever (up to 104 degrees F).
• Cough (which is usually dry but can be severe) and sometimes a runny nose and sore throat.
• Children may experience vomiting, diarrhea, and ear infections, as well as other flu symptoms.
• The symptoms usually resolve in 4 to 5 days, although some people can experience coughing and feelings of illness for more than 2 weeks. In some cases, flu can become more severe or make other conditions worse. 

Transmitting the Virus. The virus is spread primarily when a person with the flu coughs or sneezes near someone else. Adults with flu typically spread it to someone else from 1 day before symptoms start to about 5 days after symptoms develop. Children can spread the infection for more than 10 days after symptoms begin, and young children can transmit 6 days or even earlier before the onset of symptoms. People with severely compromised immune systems can transmit the virus for weeks to months.

Flu Strains. A virus is a cluster of genes wrapped in a protein membrane, which is coated with a fatty substance that contains molecules called glycoproteins. Strains of the flu are identified according to the number of membranes and type of glycoproteins present.

Click the icon to see an image of a virus.

The two major flu strains are referred to as A and B:

• Influenza A is the most widespread and can even infect animals and humans. Influenza A is the cause of the major pandemics (worldwide epidemics) of influenza that have occurred. It is usually further categorized by two subtypes based on two substances that occur on the surface of the viruses: hemagglutinin (H) and neuraminidase (N).
• Influenza B infects only humans. It is less common than Type A, but is often associated with specific outbreaks, such as in nursing homes.

Based on a final analysis of the 2001-2002 flu season, nearly 90% were type A and about 10% were type B. Influenza A usually causes more severe disease than type B. There is some concern, however, that since influenza B has been less common in the past few years, some people, particularly small children, may have fewer antibodies to it and so may be at higher risk for severe infection.

Avian Influenza (Bird Flu)

Although the risk of lethal viruses is generally low, scientists are greatly concerned about a particular virus called H5N1, which causes avian influenza (bird flu). Since 1997, the H5N1 virus has triggered deadly outbreaks in poultry across Southeast Asia. As of February 6, 2006, at least 165 people had been infected with the bird flu in 6 countries. More than half of these people have died, according to the World Health Organization. No cases have been seen in the United States.

So far, the virus has spread from birds to humans.  The virus does not seem to be easily spread from person to person. However, scientists and public health officials are monitoring the spread of H5N1 and working to contain it. Efforts include slaughtering infected birds, developing new vaccines, and stockpiling antiviral drugs such as oseltamivir (Tamiflu). Many poor nations have limited resources and already contend with other serious health problems, including HIV-AIDS. If H5N1 does mutate and spread, the consequences could be especially severe for these countries.

Diagnosis

Differentiating between a cold and flu may be difficult. Cold symptoms are nearly always less severe than those of the flu.

Comparing Colds and Flus

Diagnosing the Flu

A number of tests are available to isolate and identify the viruses responsible for some respiratory infections. They are generally not needed, since most cases of the flu are self-evident. However, such tests can be very helpful in confirming or ruling out the flu. If a doctor believes a diagnosis would help, samples using a swab should be taken from the nasal passages or throat within 4 days of the first symptoms.

A nasopharyngeal culture is a test used to identify disease-causing organisms in nasal secretions. Nasopharyngeal cultures are useful in identifying Bordetella pertussis and Neisseria meningitidis (types of bacteria). The culture may help determine appropriate antibiotic therapy.

A number of rapid tests for the flu are available that can produce results in less than 30 minutes, but vary on the specific strain or strains that they can detect. They are not as accurate as a viral culture, however, in which the virus is reproduced in the laboratory; culture results can take 3 to 10 days. Blood tests can also document the infection several weeks after symptoms appear.

Diagnosing Avian Influenza

In February 2006, the U.S. Food & Drug Administration approved a new, faster test for diagnosing strains of avian influenza (bird flu) in people suspected of having the virus. The test is called the Influenza A/H5 (Asian lineage) Virus Real-time RT-PCR Primer and Probe Set. The test gives preliminary results within 4 hours. Older tests required 2 to 3 days.

Ruling out Other Causes of Congestion

Ruling out Allergic Rhinitis. Symptoms of allergic rhinitis include nasal obstruction and congestion, which are similar to the symptoms of a cold. People with allergies, however, are likely to have the following:

• Thin, clear, and runny nasal discharge
• An itchy nose, eyes, or throat
• Recurrent sneezing

There are two forms of allergic rhinitis:

• Symptoms that appear only during allergy season are called allergic rhinitis, commonly known as hay or rose fever. [For more information see In-Depth Report # 77 Allergic Rhinitis.]
• Allergens in the house, such as house dust mites, molds, and pet dander, can cause year-long allergic rhinitis, referred to as perennial rhinitis.

Click the icon to see an image of common allergens.

Ruling out Sinusitis. The signs and symptoms suggestive of true acute sinusitis include the following:

• A return of congestion and discomfort after initial improvement in a cold (called double sickening)
• Purulent (pus-filled) nasal secretion
• A lack of response to decongestant or antihistamine
• Pain in the upper teeth or pain on one side of the head
• Pain above or below both eyes when leaning over

Children with sinusitis are less likely to have facial pain and headache and may only develop a high fever or prolonged upper respiratory symptoms (such as a daytime cough that does not improve for 11 to 14 days). When the diagnosis is unclear or complications are suspected, further tests may be required. [For more information see In-Depth Report # 62 Sinusitis.]

Ruling Out Other Causes of Coughing

Acute Bronchitis. Acute bronchitis is usually caused by a virus and in most cases is self-limiting. The cough it causes typically lasts for about 7  to 10 days, but in about half of patients, coughing can last for up to three weeks, and 25% of patients continue to cough for over 1 month.

Atypical Pneumonia. Pneumonia caused by atypical organisms (e.g., Mycoplasma pneumonia, Legionella) can cause symptoms similiar to the flu. Only laboratory tests can diagnose the difference. [For more information see In-Depth Report # 64 Pneumonia.]

Ruling out More Serious Viral Infections. Respiratory syncytial virus (RSV) and, possibly human parainfluenza viruses (HPV), are proving to be important causes of serious respiratory infections in infants, the elderly, and people with damaged immune systems. (Both also cause mild conditions.) RSV may be a much more common cause of flu-like symptoms than previously thought. In one British study of patients with flu symptoms, RSV was responsible for 22% of the cases and influenza for 32%. And among children under age five, RSV was responsible for more flu-like cases than the flu virus itself.

Pertussis. Pertussis (whooping cough) was a very common childhood illness throughout the first half of the century. Although immunizations caused a decline in cases to only 1,700 in the U.S. in 1980, the incidence has risen recently, with almost 30,000 cases reported between 1997 and 2000 (17 infants died of the disease in 2000). Many more cases are reported worldwide.

Nearly half of pertussis cases now occur in people 10 years of age or older, perhaps due to waning immunity in adolescents and adults. Such cases may be greatly underreported. One study suggested that as many as 25% of adults who see a doctor for persistent cough may actually have pertussis. It may go undiagnosed, however, because symptoms are usually mild and adults are unlikely to have the classic "whooping" cough. This is of some concern because such adults may unknowingly infect unvaccinated children. The younger the patient, the higher the risk for severe complications, including pneumonia, seizures, and even death. Children younger than 6 months are at particular risk because even with vaccination, protection is incomplete.

Ruling Out Other Causes of Sore Throat

In addition to common cold viruses, other, less frequent causes of sore throat include the following:

• Strep throat
• Sore throat related to the flu
• Foodborne and waterborne infections (Streptococcus C and G)
• An uncommon organism called Arcanobacterium haemolyticum (infection with this bacterium can mimic strep throat and may even cause a rash)
• Infectious mononucleosis ("mono")
• Herpesvirus 1
• Pneumonias caused by the atypical organisms mycoplasma or chlamydia

Complications

Colds rarely cause serious complications. In about 1% of cases, a cold can lead to other complications, such as sinus or ear infections. It can also aggravate asthma and, in uncommon situations, increase the risk for lower respiratory tract infections.

Ear Infections. The rhinovirus infection, a major cause of colds, also commonly predisposes children to ear infections, possibly by obstructing the Eustachian tube, which leads to the middle ear. Viruses may even attack the ear directly. In one study, 74% of patients with rhinovirus colds had pressure abnormalities in their middle ear.

Sinusitis. Between 0.5% and 5% of people with colds develop sinusitis, an infection in the sinus cavities (air-filled spaces in the skull). Sinusitis is usually mild, but if it becomes severe, antibiotics generally eliminate further problems. In rare cases, however, sinusitis can be serious.

Lower Respiratory Tract Infections. The common cold poses a risk for bronchitis and pneumonia in nursing home patients and other people who may be susceptible to infection. Some experts believe that the rhinovirus may play a more significant role than the flu in causing lower respiratory infections in such people.

Aggravation of Asthma. Rhinovirus infections can acerbate asthma in both children and adults and has reported to be the most common infectious organism associated with asthma attacks. Some studies have reported the common cold being associated with between 33 - 71% of severe asthma episodes. Research suggests that colds promote allergic inflammation and increase the intensity of airway responsiveness for weeks.

Complications of Influenza

In general, the flu is usually self-limited and not serious. About 1% of people who contract the flu end up in the hospital. An estimated 36,000 people currently die each year of influenza-related complications. The highest risks for serious complications occur in people over 65 years old and in those with other medical conditions. Influenza A is the most severe strain and causes an estimated average of 142,000 hospitalizations per year. Influenzas B tends to be milder.

Pneumonia. Pneumonia is the major serious complication of influenza and can be very serious. It can develop about 5 days after viral influenza. Older adults account for more than 90% of the deaths caused by influenza and pneumonia. The growing elderly population will most likely cause an increase in deaths from influenza. Nursing homes patients are especially hard-hit by flu epidemics, with fatality rates as high as 30%.  Flu-related pneumonia nearly always occurs in high-risk individuals such as the following:

• People with weakened immune systems, such as AIDS patients.
• Very young children -- may be difficult to tell whether pneumonia is related to influenza or caused by respiratory syncytial virus (RSV)
• Hospitalized patients and anyone with serious medication conditions, such as diabetes or heart, circulation, or lung disorders, particularly chronic lung disease
• Drug abusers who use needles

Combinations of these factors further increase the risk. It should be noted that pneumonia is an uncommon outcome of influenza in healthy adults.

Complications in the Central Nervous System in Children. Influenza increases the risk for complications in the central nervous system of small children. In a 2001 Chinese study, children hospitalized with influenza A had a higher risk for fever related seizures than children with other upper respiratory tract infections. In rare cases, influenza can lead to meningitis and encephalitis (inflammations in the central nervous system). The risks decline after a child turns 1 year old, but are still high in children aged 3 to 5 years old.

Pandemics

Every year, influenza strikes millions of people worldwide. Influenza epidemics are most serious when they involve a new strain against which most people are not immune. Such global epidemics (“pandemics”) can rapidly infect more than one fourth of the world's population. For example, the Spanish flu in 1918 and 1919 killed an estimated 20 million people in the U.S. and Europe and 17 million in India. With modern society’s dependence on airline travel, an influenza pandemic could potentially inflict catastrophic damage on human lives and disrupt the global economy.

The influenza virus mutates rapidly as it moves from species to species. Most type A influenza strains first develop in migratory waterfowl populations. While most avian influenza (“bird flu”) virus strains are relatively harmless, a few subtypes develop into “highly pathogenic avian influenza” that can be deadly for domesticated poultry and livestock -- and, as recent events have shown, even humans. The medical community is now greatly concerned about the H5N1 bird flu virus, which has infected many people in several countries, and has lead to death. People can become infected from contact with contaminated chickens and pigs. Scientists’ greatest fear is the emergence of a highly contagious virus that spreads from person to person and causes severe illness or death.

Risk Factors

Colds and flus are spread primarily when an infected person coughs or sneezes near someone else. Everyone gets a cold or upper respiratory infection at some time:

• On average, every American has two to four colds a year.
• Each year, there are between 18 to 20 million cases of respiratory infections caused by influenza.

Age

The very young and the very old are at higher risk for upper respiratory tract infections and for complications from them.

Children. Young children are prone to colds and may have 8 to 12 colds every year. Millions of cases of influenza develop in American children and adolescents each year.

Before the immune system matures, all infants are susceptible to infections, with a possible frequency of one cold every 1 or 2 months. Smaller nasal and sinus passages also make children more vulnerable than older children and adults. Infections gradually diminish as they grow, until at school age their rate is about the same as an adult's. There is almost never cause for concern when a child has frequent colds unless they become unusually severe or more frequent than usual.

The Elderly. The elderly have diminished cough and gag reflexes and faltering immune systems and are at greater risk for serious respiratory infections than are young and middle-aged adults.

Exposure to Smoke and Environmental Pollutants

The risk of respiratory infections is increased by exposure to cigarette smoke, which can injure airways and damage the cilia (tiny hair-like structures that help keep the airways clear). Toxic fumes, industrial smoke, and other air pollutants are also risk factors. Parental smoking increases the risk of respiratory infections.

Medical Conditions

People with AIDS and other medical conditions that damage the immune system are extremely susceptible to serious infections.

Cancers, especially leukemia and Hodgkin's disease, put patients at risk. Patients who are on corticosteroid (steroid) treatments, chemotherapy, or other medications that suppress the immune system are also prone to infection.

People with diabetes are at higher risk for flu.

Certain genetic disorders predispose people with these problems to respiratory infections. They include sickle-cell disease, cystic fibrosis (which causes mucus abnormalities), and Kartagener's syndrome (which results in malfunctioning cilia).

People under Stress

Much evidence suggests that stress increases one's susceptibility to a cold. In one study, people with high stress levels averaged 2.7 upper respiratory infections during a six-month period and those reporting low stress averaged 1.5 infections. Stress appears to increase the risk for a cold regardless of lifestyle or other health habits. And once a person catches a cold or flu, stress can exacerbate symptoms.

It is not clear why these events occur. Some experts believe that stress alters specific immune factors, which cause inflammation in the airways. One 2001 study reported that the only people who got sick after experiencing short stress were those whose body responded to stress with high levels of cortisol, a stress hormone, coupled with a low immune response.

Excessive Exercise

In people who already have colds, exercise has no effect on the illness' severity or duration of the infection. High-intensity or endurance exercises, however, appear to suppress the immune system while they are being performed. Some highly trained athletes, for instance, report being susceptible to colds after strenuous events. People should avoid strenuous physical activity when they have high fevers or widespread viral illnesses. Note: Very low fat diets appear to worsen this dampening effect on the immune system. A higher fat-diet may help redress this imbalance (omega-3 fatty acids, found in fish and canola oil are preferred). Whether carbohydrate loading provides much additional value is not clear.

Seasonal Incidence

Colds and flus occur predominantly in the winter. Flu season typically starts in October and lasts into mid March. In 1999, for example, doctors' office visits significantly increased beginning in December and influenza activity peaked during the first 2 weeks in February.

The reasons for this seasonal bias are not due to the cold itself, but to other factors. Certainly, flus and colds are more like to be transmitted in winter because people spend more time indoors and are exposed to higher concentrations of airborne viruses. Dry winter weather also dries up nasal passages, making them more susceptible to viruses. Some experts theorize that the high rates of viral infections in winter may be due to certain immune factors, which react to light and dark and affect a person's susceptibility to viruses.

Traveling in Trains, Buses, and Planes

Traveling in close contact with people, whether on trains, planes, or buses, can increase the risk for respiratory infections. (A 2002 study suggested that the risk for a cold was about 20% after flying.) There has been particular concern that aircraft air that is recirculated can increase the risk for such infections. The same 2002 study, however, reported no difference in colds and flus among those who traveled in planes with fresh air versus recirculated air.

Day Care Centers

Children who attend day care may have an increase risk of colds. However, a 2002 study suggested that although children in day care centers incur higher rates of the common cold in the preschool years, they have lower cold rates in their first years of regular school. The colds they catch in day care, then, may bestow some immunity to future colds for a few years. By age 13, such protection has worn off. There is also some evidence that frequent colds in young children may help protect against future allergies and asthma.

Prevention

Because colds and flus are easily spread, everyone should always wash his or her hands before eating and after going outside. Ordinary soap is sufficient. Waterless hand cleaners that contain an alcohol-based gel are also effective for every day use and may even kill cold viruses. (They are less effective, however, if extreme hygiene is required. In such cases, alcohol-based rinses are needed.)

Antibacterial Products

Antibacterial soaps add little protection, particularly against viruses. In fact, one study suggests that common liquid dish washing soaps are up to 100 times more effective than antibacterial soaps in killing respiratory syncytial virus (RSV), which is known to cause pneumonia. Wiping surfaces with a solution that contains one part bleach to 10 parts water is very effective in killing viruses.

Temperature

Colds are not caused by insufficiently warm clothes or by going outside with wet hair. A 2002 study reported, however, that in older adults cold temperatures can thicken the blood and may increase the risk for respiratory infections and even circulatory and heart problems. (This danger does not appear to affect people under 55 years of age.)

Dietary Factors

Foods Containing Lactobacilli (Good Bacteria). Researchers are also studying the possible protective value of certain strains of lactobacilli bacteria found in the intestines. Some of these strains, particularly acidophilus, are used to make yogurt. According to one Finnish study, children attending day care who ate milk containing the strain lactobacilli GG could reduce respiratory infections in these children by 10 - 20%.  (The strain used was not the kind found in most commercial yogurt products.)

Vitamins. Studies are mixed whether vitamin supplements protect against upper respiratory infections. Large doses of vitamin C, for example, may help reduce the duration of a cold, but they do not appear to protect against one in the first place, even after exposure to a cold virus. Two studies in 2002 on multivitamins reported opposite results, with one finding fewer infections and one finding no difference. It is possible that vitamin C or multivitamin supplements may be helpful in specific people, such those who are vitamin deficient or have medical problems that impair their immune systems.

Studies on vitamin E specifically have been largely negative. A 2002 study, in fact, reported a higher incidence and greater severity of respiratory infections in older adults who took 200 mg of vitamin E daily.

Factors Associated with a Lower Risk for Respiratory Infections

Breastfeeding. Some evidence suggests that women who breastfeed reduce the risk of respiratory infections in their children.

Low Stress and Active Social Life. More than one study has reported that people with low stress who also have an active social life have fewer colds than people who have high stress levels or those who have low stress and few social connections.

Treatment

The following are some food and fluid recommendations. Most will not cure a cold but may help a person deal better with the symptoms:

• Drinking plenty of fluids and getting lots of rest when needed is still the best bit of advice to ease the discomforts of the common cold. Water is the best fluid and helps lubricate the mucous membranes. (There is no evidence that drinking milk will increase or worsen mucus, although milk is a food and should not serve as fluid replacement.)
• Chicken soup does indeed help congestion and body aches. The hot steam from the soup may be its chief advantage, although laboratory studies have actually reported that ingredients in the soup may have anti-inflammatory effects. In fact, any hot beverage may have similar soothing effects from steam. Ginger tea, fruit juice, and hot tea with honey and lemon may all be helpful.
• Spicy foods that contain hot peppers or horseradish may help clear sinuses.
• Foods rich in vitamins A and C are always recommended and may be helpful during a respiratory infection. They include oranges, kiwi, and tomatoes for C and sweet potatoes, spinach, and broccoli for A.

Vitamins

Different studies have found that large doses of vitamin C reduce the duration of a cold by a range of 5 - 50%. Some precautions against taking high doses of vitamin C include the following:

• High doses of vitamin C may cause headaches and intestinal and urinary problems and even kidney stones.
• Because ascorbic acid increases iron absorption, people with certain blood disorders, such as hemochromatosis, thalassemia, or sideroblastic anemia, should particularly avoid high doses.
• Large doses can also interfere with anticoagulant medications, blood tests used in diabetes, and stool tests.
• Vitamin E or multivitamin supplements do not appear to be helpful in reducing symptoms of the cold.

Zinc

Zinc appears to have certain important effects on the immune system and it may have a direct effect on viruses. How it works is not entirely clear, however. Zinc preparations in lozenge or nasal gel form are now available as cold treatments. Studies are very mixed on the effects of zinc on colds. The variance may be due to different zinc preparations. Studies are underway to determine advantages, if any. Some examples include the following:

• A nasal gel (Zicam), which contains zinc gluconate, has shown some success, possibly because the gel sticks to the nasal passages long enough for the zinc to interact with the virus. In a 2003 study, for example, the nasal gel shortened the duration and severity of the cold compared to placebo when it was started within 14 to 48 hours of the onset of symptoms. The supports earlier studies reporting that it shortened the duration of a cold by about two days.
• Zinc lozenges are showing mixed results. One 2000 study suggested that the use of zinc acetate lozenges (e.g., Fast-Dry, Galzin) may be more effective and have a better taste than other formulations, such as zinc gluconate (Cold-Eeze, Orazinc). On the other hand, a 2002 study reported that zinc gluconate reduced cold duration significantly. To further confuse matters, the two zinc lozenge preparations were directly compared in a 2000 study, and neither was effective. The reasons for these conflicting results are not clear.
• A small 2001 study on a nasal spray preparation found no benefits. The spray preparation had less zinc than the nasal gel.

In any case, no one with an adequate diet and a healthy immune system should take zinc for prolonged periods for preventing colds.

Side Effects. Side effects, particularly of the lozenge form, include the following:

• Dry mouth
• Constipation
• Nausea
• Bad taste (possibly only with zinc gluconate lozenges)
• Severe vomiting, dehydration, and restlessness (signs of overdose, seek medical help)
• Allergic response (rare)

Food and Drug Interactions. Zinc may also interact with drugs or other elements.

• It may reduce absorption of certain antibiotics.
• Foods high in calcium or phosphorus may reduce zinc absorption.
• In high doses and for long periods of time zinc can cause copper deficiencies.

Medications for Mild Pain and Fever Reduction

Many people take medications to reduce mild pain and fever. Adults most often choose aspirin, ibuprofen (Advil), or acetaminophen (Tylenol).

The following are recommendations for children:

• Acetaminophen (Tylenol) or ibuprofen (usually Advil or Motrin) is the pain-reliever of choice in children. Most pediatricians advise such medications for children who run fevers over 101 degrees F. Some suggest alternating the two agents, although there is no evidence that this regimen offers any benefits, and it might be harmful.
• Aspirin and aspirin-containing products are virtually never recommended for children or adolescents. Reye's Syndrome, a very serious condition, has been associated with aspirin use in children who have flu symptoms or chicken pox.

Some studies are suggesting that these anti-fever agents may actually reduce the body's immune response against cold and flu viruses and prolong symptoms. A 2000 study, for example, reported a longer flu duration in people who took aspirin or acetaminophen (although people still felt better). (In the study, these drugs did not appear prolong other illnesses, including Rocky Mountain spotted fever and shigellosis.) Nevertheless, most doctors strongly recommend lowering fevers in children, since high fevers can sometimes cause seizures.

Nasal Strips

Nasal strips (Breathe Right) are placed across the lower part of the nose and pull the nostrils open. These strips may open the nasal passages and ease congestion due to a cold, sinusitis, or hay fever. As of yet, there is no scientific evidence that they offer such benefits.

Nasal Wash

A nasal wash can be helpful for removing mucus from the nose. A saline solution can be purchased at a drug store or made at home. One study reported that neither a homemade solution (using one teaspoon of salt and one pinch of baking soda in a pint of warm water) nor a commercial hypertonic saline nasal wash had any effect on symptoms. Further, one preliminary study found that over-the-counter saline nasal sprays that contain benzalkonium chloride as a preservative may actually worsen symptoms and infection.

Some physicians, however, advocate a traditional nasal wash that has been used for centuries and is different from that used in the study. It contains no baking soda and uses more fluid for each dose and less salt. The nasal wash should be performed several times a day.

Simple method for administering a nasal wash is the following:

• Lean over the sink head down.
• Pour some solution into the palm of the hand and inhale it through the nose, one nostril at a time.
• Spit the remaining solution out.
• Gently blow the nose.

The solution may also be inserted into the nose using a large rubber ear syringe, available at a pharmacy. In this case the process is the following:

• Lean over the sink head down.
• Insert only the tip of the syringe into one nostril.
• Gently squeeze the bulb several times to wash the nasal passage.
• Then press the bulb firmly enough so that the solution passes into the mouth.
• The process should be repeated in the other nostril.

Nasal-Delivery Decongestants

Nasal-delivery decongestants are applied directly into the nasal passages with a spray, gel, drops, or vapors. Nasal forms work faster than oral decongestants and have fewer side effects. They often require frequent administration, although long-acting forms are now available. Ingredients and brands of nasal decongestants include the following:

Long Acting Nasal-Delivery Decongestants. They are effective in a few minutes and remain so for 6 to 12 hours. The primary ingredient in long-acting decongestant is the following:

• Oxymetazoline: Brands include Vicks Sinex (12-hour brands), Afrin (12-hour brands), Dristan 12-Hour, Good Sense, Nostrilla, Neo-Synephrine 12-Hour.
• Xylometazoline: Inspire, Otrivin, Natru-vent.

Short-Acting Nasal-Delivery Decongestants. The effects usually last about four hours. The primary ingredients in short-acing decongestants are the following:

• Phenylephrine: Neo-Synephrine (mild, regular, high-potency), 4-Way, Dristan Mist Spray, Vicks Sinex.
• Naphazoline (Naphcon Forte, Privine).

Dependency and Rebound. The major hazard with nasal-delivery decongestants, particularly long-acting forms is a cycle of dependency and rebound effects. The 12-hour brands pose a particular risk for this effect. This effect works in the following way:

• With prolonged use (more than three to five days), nasal decongestants lose effectiveness and even cause swelling in the nasal passages.
• The patient then increases the frequency of their dose. The congestion worsens and the patient responds with even more frequent doses, in some cases to as often as every hour.
• Individuals then become dependent on them.

Tips for Use. The following precautions are important for people taking nasal decongestants:

• When using a nasal spray, spray each nostril once. Wait a minute to allow absorption into the mucosal tissues, and then spray again.
• Keep the nasal passages moist. All forms of nasal decongestants can cause irritation and stinging. They also may dry out the affected areas and damage tissues.
• Do not share droppers and inhalators with other people.
• Use decongestants only for conditions requiring short-term use, such as before air travel or for a single-allergy attack. Do not take them more than three days in a row. With prolonged use, nasal decongestants become ineffective and result in the so-called rebound effect and dependence.
• Discard sprayers, inhalators, or other decongestant delivery devices when the medication is no longer needed. Over time, these devices can become reservoirs for bacteria.
• Discard the medicine if it becomes cloudy or unclear.

Oral Decongestants

Oral decongestants also come in many brands, which mainly differ in their ingredients. The most common active ingredient is pseudoephedrine (Sudafed, Actifed, Drixoral).

Side Effects of Decongestants. Decongestants have certain adverse effects, which are more apt to occur in oral than nasal decongestants and include the following:

• Agitation and nervousness.
• Drowsiness (particularly with oral decongestants and in combination with alcohol).
• Changes in heart rate and blood pressure.
• Avoid combinations of oral decongestants with alcohol or certain drugs, including monoamine oxidase inhibitors (MAOI) and sedatives.

Note: In November of 2000 the Food and Drug Administration (FDA) banned products, including decongestants, which contained phenylpropanolamine (PPA). This action was in response to a few reports of an increased risk of stroke. (Stroke tended to occur in people who took diet suppressants containing PPA rather than decongestants. In any case, serious events were still very rare.) All major brands that previously contained PPA have now substituted other active ingredients (usually pseudoephedrine) and are safe to use. Anyone with old forms of any decongestant should check the labels and discard them if they contain phenylpropanolamine. It should be noted that PPA has been used in dozens of medications for over 50 years. Extreme concern, therefore, is unwarranted.

Individuals at Risk for Complications from Decongestants. People who may be at higher risk for complications are those with certain medical conditions, including disorders that make blood vessels highly susceptible to contraction. Such conditions include the following:

• Heart disease
• High blood pressure
• Thyroid disease
• Diabetes
• Prostate problems that cause urinary difficulties
• Migraines
• Raynaud's phenomenon
• High sensitivity to cold
• Emphysema or chronic bronchitis

People taking medications that increase serotonin levels, such as certain antidepressants, anti-migraine agents, diet pills, St. John's Wort, and methamphetamine. The combinations can cause blood vessels in the brain to narrow suddenly, causing severe headaches and even stroke.

Anyone with these conditions should not use either oral or nasal decongestants without a doctor's guidance. Other groups who should also use these agents with caution are the following:

• Anyone who is pregnant should not use these agents without consulting a physician.
• Children appear to metabolize decongestants differently than adults. Decongestants should not be used at all in infants and small children, who are at particular risk for side effects that depress the central nervous system. Such symptoms cause changes in blood pressure, drowsiness, deep sleep, and, rarely, coma.

Cough Remedies

Major studies have indicated that over-the-counter cough medicines are not very effective, but they are also not harmful.

• For thick phlegm, patients may try cough medications that contain guaifenesin (Robitussin, Scot-Tussin Expectorant), which loosens mucus. Patients should not suppress coughs that produce mucus and phlegm; it is important to expel this substance. To loosen phlegm, patients should drink plenty of fluids and use a humidifier or steamer.
• For patients with a dry cough, a suppressant may be useful, such as one that contains dextromethorphan (Drixoral Cough, Robitussin Maximum Strength Cough Suppressant).

Medications that contain both a cough suppressant and an expectorant are not useful and should be avoided. Medicated cough drops that contain dextromethorphan are not very useful. A patient is just as likely to find relief from hard candy or lozenges.

Remedies for Sore Throat Associated with Colds

Sore throats that are associated with colds are generally mild. The following may be helpful:

• Cough drops, throat sprays, or gargling warm salt water may help relieve sore throat and reduce coughing.
• Throat sprays that contain phenol (e.g., Vicks Chloraseptic) may be particularly helpful. Phenol has anti-bacterial properties. In one study, patients with sore throat who used the spray experienced faster resolution of the cold itself, including fever, headache, and other symptoms compared to a dummy medication. None were taking antibiotics.
• Cough drops that contain menthol and mild anesthetics, such as benzocaine, hexylrescorincol, phenol, and dyclonine (the most potent), may soothe a mild sore throat.
• One health professional suggested that people with sore throats from postnasal drip might try taking a teaspoon of liquid antacid. They shouldn't drink anything afterward, since the intention is to coat the throat and help neutralize the acid in the mucus that might be causing pain.

If soreness in the throat is very severe and does not respond to mild treatments, the patient or parent should check with the physician to see if a strep throat is present, which would require antibiotics. In one study only 17% of sore throats in adults were caused by Group A streptococcus, the bacterium responsible for strep throat. Nevertheless, antibiotics were prescribed in 73% of patients.

Combination Cold and Flu Remedies and Antihistamines

Dozens of remedies are available that combine ingredients aimed at more than one cold or flu symptom. In general, they do no harm, but they have the following problems:

• Some ingredients may produce side effects without even helping a cold.
• In some cases, the ingredients conflict (such as a cough expectorant and a cough suppressant).
• In other cases, a patient may wish to increase the dosage to improve one symptom, which serves to increase other ingredients that do no good and, in higher doses, may cause side effects.

Note on Antihistamines. Many combination remedies contain antihistamines. Antihistamines are used for allergies and not generally recommended to relieve the symptoms of the common cold. Some evidence suggests, however, that they may have some value.

One study has indicated that older so-called first-generation antihistamines may reduce cold symptoms; experts postulate that their benefits for the cold are likely to be due to the drowsiness they cause. Such antihistamines include Benadryl, Tavist, and Chlor-Trimeton. The newer, second-generation antihistamines (Claritin, Allegra, Zyrtec) do not have these effects and also appear to have no benefits against colds.

Another interesting study reported high levels of histamine in the urine of patients infected with type A influenza, suggesting that anti-histamines may actually have some real value for viral infections, include flus and colds. More research is needed, however, before the significance of these findings is known.

Medications

For mild influenza, symptom relief is similar to that for colds. Vaccines are available to prevent influenza (See section on Viral Influenza Vaccines).

Two classes of antiviral agents have been developed to treat influenza A, B, or both: M2 inhibitors and neuraminidase inhibitors. The CDC recommended in January 2006 that the M2 inhibitors should no longer be used to treat flu during the 2005 – 2006 season because many strains of influenza A have become resistant to these drugs. M2 inhibitors have never been active against influenza B, a milder infection. Until recently, these agents were considered appropriate for prevention and treatment of the flu.

Anti-Viral Drugs: M2 Inhibitors

Brands and Benefits. Amantadine (Symmetrel) and rimantadine (Flumadine) are M2 inhibitors. They have the following benefits against drug-sensitive strains of influenza A:

• Both offer protection against influenza A and prevent severe illness if a person contracts the infection. (To be effective it must be administered within 2 days of onset.)
• They may shorten the duration and lessen the severity of the flu if given within 48 hours of onset of symptoms.

Limitations. Drawbacks of M2 inhibitors include:

• Viral resistance to these agents is rapidly emerging. For this reason, the CDC now recommends that M2 inhibitors should not be used during the 2005 – 2006 flu season in the U.S.
• M2 inhibitors are not effective against influenza B.
• Neither has proven to reduce the risk for complications, including pneumonia and bronchitis.

Side Effects. Both agents occasionally cause nausea, vomiting, indigestion, insomnia, and hallucinations. Amantadine affects the nervous system and about 10% of people experience nervousness, depression, anxiety, difficulty concentrating, and lightheadedness. Rimantadine is less likely to do so. Rarely, amantadine can cause seizures, usually in elderly people already at risk for psychiatric symptoms.

Note: Amantadine is a standard treatment for Parkinson’s disease and should be continued for that condition.

Anti-Viral Drugs: Neuraminidase Inhibitors

Brands and Benefits. Zanamivir (Relenza) and oseltamivir (Tamiflu) are called neuraminidase inhibitors. They are newer agents that have been designed to block a key viral enzyme, neuraminidase, which is involved with viral replication. According to a major review of over 50 studies published in 2006, these drugs are effective against the flu in about 60% of cases.

Both zanamivir and oseltamivir have the following benefits:

• Neuraminidase inhibitors are effective for treating both A and B strains of influenza. (M2 inhibitors are only effective against type A.)
• They shorten the duration of the flu by 1 to 3 days.
• They may help reduce transmission of the virus.
• They may have a lower risk than M1 inhibitors for emerging viral strains that are resistant to their effects.
• They have fewer serious side effects than the M2 inhibitors.
• Both have some benefits for preventing influenza. Only oseltamivir has been approved for this purpose, however, and only in people over 13.
• They may reduce complications of influenza, although this needs to be confirmed. It is not yet known if they have any effect on overall survival rates.
• Oseltamivir is the only drug studied in avian flu cases. Although it is active in lab experiments, it has not been successful clinically. Experience is very limited, however, and it is not clear whether people infected with avian flu received the drug in time for it to be useful.

Limitations and Side Effects. Although they have many advantages compared to the M2 inhibitors, they are much more expensive. They also need to be taken within 2 days of symptoms to be effective. Neither is effective against influenza-like illness. There are also some differences between the two agents that could be significant for some individuals:

• Zanamivir (Relenza) is administered as a nasal spray or inhaler. People with asthma or other lung disorders may experience airway spasms and should use this drug with caution. Side effects are generally minor in most patients. Of concern, however, was a 2001 British study, which found that a majority of elderly patients were not able to properly use the zanamivir (Relenza) inhaler device, making the medicine virtually ineffective in these cases. The study was small, however, and other reports suggest that zanamivir is sill effective in this older group.
• Oseltamivir comes in capsule and liquid form. Side effects are also minor but about 10 - 15% of patients experience nausea and vomiting. Patients with kidney dysfunction should take lower doses.

Candidates. Their current use in different age and patient groups are as follows:

• Adults. Both are approved for treatment in adult patients.
• Children. Oseltamivir is approved for use in children age one and older. Studies report significant reduction in symptoms and in the incidence of ear infections. Zanamivir is approved for children over seven, and studies are currently underway to determine its safety in younger children.
• High-Risk Patients. Recent studies indicate they are safe and effective in patients with serious medical problems or other conditions that put them at risk for complications of flu.

Comparing Anti-Viral Medications for the Flu

Antiviral drugs are not a substitute for vaccines. Oseltamivir and Relenza may be important as add-on protection agents during a serious epidemic or pandemic, when used in conjunction with public health measures such as quarantine and rigorous hygiene practices.

Oseltamivir is the only drug studied for protection against avian flu. Although it is active in lab experiments, it has not been successful clinically. Experience is very limited, however, and it is not clear whether people infected with avian flu received the drug in time for it to be useful. Further study is necessary.

Viral Influenza Vaccines

Description of Vaccines. Vaccines against influenza employ inactivated (not live) viruses. They are designed to provoke the immune system to attack antigens contained on the surface of the virus. (Antigens are foreign molecules that the immune system specifically recognizes as alien and so targets for attack.)

Unfortunately, the antigens in these influenza viruses undergo genetic alterations (called antigenic drift) over time, so they are likely to become resistant to a vaccine that worked in the previous year. Vaccines are then redesigned annually to match the current strain.

• Influenza A. The influenza A virus is further categorized by primary molecular antigens (hemagglutinin and neuraminidase), which serve as the targets for the vaccines. Influenza A is a particular problem because it can infect other species, such as pigs or chickens, and undergo major genetic reassortments.
• Influenza B viruses tend to be more stable than influenza A viruses, but they too vary. Although influenza B has been far less common than A, a vaccine for type B is important because experts are concerned that small children will not have developed any immunity to the virus and will experience severe flu if they are exposed to type B.

A live but weakened intranasal vaccine (FluMist) is proving to be effective and safe in healthy people aged 5 to 49 years and has been approved by the FDA. It is known as a live, attenuated, intranasal influenza vaccine (LAIV). The vaccine is engineered to grow only in the cooler temperatures of the nasal passages, not in the warmer lungs and lower airways. It boosts the specific immune factors in the mucous membranes of the nose that fight off the actual viral infections. FluMist is employed using a nasal spray and in one study provided protection against the flu in up to 93% of children. According to a broad Canadian study in 2004, one to two doses of the intranasal spray gave children better protection than injected vaccines.

Timing and Effectiveness of the Vaccine. Ideally, appropriate candidates should be vaccinated every October or November. However, it may take longer for a full supply of the vaccine to reach certain locations. In such cases, the high-risk groups should be served first.

Antibodies to the influenza virus usually develop within 2 weeks of vaccination, and immunity peaks within 4 to 6 weeks, then gradually wanes.

• Because children under age 9 do not develop strong immune responses to one dose, the CDC recommends two vaccinations given 1 month apart.
• Early research also suggests that it may be equally effective to administer children’s vaccinations in the spring and fall, rather than one month apart; further study is ongoing.
• It should be noted that if an individual develops influenza symptoms and is accurately diagnosed in time, vaccination of the other members of the household within 36 – 48 hours affords effective protection to those individuals, according to a 2004 Canadian analysis of multiple studies.

In healthy adults, immunization typically reduces the chance of illness by about 70 - 90%. The current flu vaccines may be slightly less effective in certain patients, such as the elderly and those with certain chronic diseases. Even in people with a weaker response, however, the vaccine is usually protective against serious flu complications, particularly pneumonia. In fact, among the elderly, interesting studies are now suggesting that influenza vaccination may help protect against stroke, adverse heart events, and death from all causes.

Children Who Should Be Vaccinated. The following children over 6 months should be vaccinated against influenza:

• The American Academy of Pediatrics (AAP) and the CDC recommend influenza vaccination in all healthy children between 6 and 2 years of age. In addition, any child over the age of 2 years with a condition that requires regular medical care or who has been hospitalized for a serious illness (particularly lung or kidney disease, diabetes, sickle-cell, or immune deficiencies). If parents are concerned about vaccines that contain the mercury preservative thimerosal, they can ask their doctor about reduced-thimerosal flu vaccine.
• Children who are receiving long-term aspirin therapy should also be immunized against the flu because they are at higher risk for Reye's syndrome, a life-threatening disease, if they get the flu.
• Some experts now advocate flu shots for all school-age children. Emerging research indicates that children are responsible for transmitting the vast majority of cases of seasonal flu, and that routine vaccination of school-age children would considerably reduce transmission rates throughout communities.

Of note: There has been some question concerning influenza vaccinations because of some reports that vaccines may worsen asthma. Recent and major studies have been reporting, however, that the vaccination is safe for children with asthma. It is also very important for these patients to reduce their risk for respiratory diseases. Still, 90% of asthma patients remain unvaccinated.

Older Children and Adults Who Should Be Vaccinated. The following, in order of priority, are the population groups who should be vaccinated each year. The first two groups have the highest need for influenza vaccinations and are given top priority:

• All adults 50 years and older. Vaccinated older adults have lower hospitalization rates than unvaccinated peers. Evidence now suggests that vaccination may help protect against adverse heart events (including after heart surgeries), stroke, and death from all causes in the elderly. Still, studies suggest that only two thirds of this group are vaccinated, mostly because of unwarranted fears of ineffectiveness or adverse effects.
• People of any age at high risk for serious complications from influenza. Such people include those with heart disease, lung problems, immune deficiencies, diabetes, kidney disease, or chronic blood disease. Those with any condition that may compromise respiratory function or the handling of respiratory secretions, including people with cognitive dysfunction, spinal cord injuries, seizure disorders, or other neuromuscular disorders, are included in this group. (There have been concerns about the safety of the vaccinations in certain high-risk patients such as those with HIV or asthma. Studies now suggest that the vaccine is generally safe in these patient groups. Furthermore, their risk for serious complications from influenza outweighs any potential adverse effects from the vaccines.)
• Adults between the ages of 50 and 64 who have chronic medical conditions. (The US Advisory Committee on Immunization Practices (ACIP) suggests that all adults over age 50 should be vaccinated, although this is not recommendation of the CDC.) People (such as household members or healthcare workers) in contact with individuals who are at high-risk for complications from influenza.
• All healthcare workers should be vaccinated, according to ACIP’s 2005 recommendations.
• Household members in contact with individuals who are at high-risk for complications from influenza should be vaccinated.

Other adults who should consider influenza vaccinations include:

• People at risk for complications for influenza and who are traveling to the tropics at any time or to the Southern Hemisphere between April and September.
• Pregnant women who are at risk for complications of influenza and who will be in their second or third trimester during flu season. (Vaccinations should usually be given after the first trimester. Exceptions may be women who are in their first trimester during flu season and their risk from complications of the flu is higher than any theoretical risk to the baby from the vaccine.)
• People such as firemen or policemen who are critical for public safety.

Negative Effects. Possible negative responses include:

• Allergic Reaction. Newer vaccines contain very little egg protein, but an allergic reaction still may occur in people with strong allergies to eggs.
• Soreness at the Injection Site. Up to two thirds of people who receive the influenza vaccine develop redness or soreness at the injection site for one or two days afterward.
• Flu-like Symptoms. Some people actually experience flu-like symptoms, called oculo-respiratory syndrome, which include cough, wheeze, tightness in the chest, sore throat, or a combination. Such symptoms tend to occur between 2 and 24 hours after the vaccination and generally last up to 2 days. These symptoms are not influenza itself but an immune response to the virus proteins in the vaccine. (Anyone with a fever at the time the vaccination is scheduled, however, should wait to be immunized until the ailment has subsided.)
• Guillain-Barre Syndrome. Isolated cases of a paralytic illness known as Guillain-Barre syndrome occurred in about one of every 100,000 people vaccinated with the swine-flu vaccine in 1976, but it has not been a problem with subsequent vaccines.

Pneumococcal Vaccines

The pneumococcal vaccine protects against S. pneumoniae (also called pneumococcal) bacteria, the most common cause of respiratory infections. There are two effective vaccines available, one called a 23-valent polysaccharide vaccine (Pneumovax, Pnu-Immune) for adults and a 7-valent conjugate vaccine (Prevnar or PCV7) for infants and young children. Experts are now recommending that more people, including healthy elderly people, be given the pneumococcal vaccine, particularly in light of the increase in antibiotic-resistant bacteria. This has created a great sense of urgency in the medical community to find effective measures for preventing infection.

Pneumococcal Vaccine in Young Children. The pneumococcal vaccine (Prevnar or PCV7) is very effective in children. Evidence suggests that this vaccination, plus the vaccination against Haemophilus influenzae (an important cause of meningitis), has led to 25,000 fewer cases of serious bacterial infections each year.

The pneumococcal vaccine is now recommended by many experts for the following groups:

• All children up to age 2 years old. The pneumococcal vaccine (Prevnar or PCV7) has now been added to the Recommended Childhood Immunization Schedule. The pneumococcal vaccine (Prevnar or PCV7) is very effective in children. Studies are suggesting that it prevents common ear infections as well as serious infections, such as pneumonia. In one study, a similar vaccine under investigation protected not only children in day care from serious respiratory infections, but their younger unvaccinated siblings had fewer infections as well.
• Children up to age five who are at risk for pneumonia or complications of influenza, such as children with sickle disease, those with immune deficiencies, or children with chronic medical conditions.
• Other children age 2 to 5 years old who are higher risk for serious pneumococcal infections should be considered for vaccinations. They include African or Native Americans, children in group child care, socially or economically disadvantaged children, or those who have had frequent or complicated acute middle ear infections within the past year. (In one study, the vaccine reduced the number of ear infections episodes by 6%.)

The recommended schedule of immunization for Prevnar (PCV7) is four doses, given at 2, 4, 6, and 12 to 15 months of age. Infants starting immunization between 7 and 11 months should have three doses. Children starting their vaccinations between 12 and 23 months only need two doses. And those who are over 2 years old need only one dose.

Pneumococcal Vaccine in Older Children and Adults. The vaccine is proving to be effective in reducing the rate of pneumonia in young adults, although not to the degree that it protects young children. Its benefits for the elderly--other than protection against bloodstream infection--is unclear. Still, pneumonia is declining among adults, which may be due to fewer infections being transmitted from vaccinated young children. Many experts now recommend the vaccine for the following older children or adults:

• All people over 65 years old. (Anyone who received the vaccine more than 5 years ago should be revaccinated.) Of note, the vaccination is protective against pneumococcal bacteremia (invasive infection) in this group, but it does not appear to protect against community-acquired pneumonia itself.
• Adults with any chronic condition that increases the risk for pneumonia. This includes patients with heart disease (e.g., congestive heart failure, cardiomyopathies), chronic lung disease (COPD or emphysema, but not asthma), or diabetes.
• Individuals with immune deficiencies (e.g., HIV) or those undergoing treatments to suppress the immune system.
• Patients with autoimmune diseases, such as rheumatoid arthritis and lupus. Unfortunately, studies suggest the vaccine may not be as effective in these patients as those with healthy immune systems. Nevertheless they are at high risk for serious respiratory infections and should be vaccinated.
• Patients with kidney disease or kidney transplants. Older people who have had transplant operations or those with kidney disease may require a revaccination after 6 years.
• Patients with problems in the spleen should be vaccinized.
• Alcoholics (especially those with cirrhosis) should receive a pneumoccocal vaccine.
• People living in long-term care facilities should be vaccinized. 
• Alaska Natives or American Indians, who may be at increased risk for pneumonia, also should receive this vaccine.

Because the vaccine is inactive, it is safe for pregnant women and people with immune deficiencies. In fact, when the vaccine is administered to pregnant women, it may actually protect their infants against certain respiratory infections.

Protection lasts for over 6 years in most people, although the protective value may be lost at a faster rate in elderly people than in younger adults. Anyone at risk for serious pneumonia should be revaccinated 6 years after the first dose, including those who were vaccinated before age 65. Subsequent booster doses, however, are not recommended.

Side Effects of the Pneumococcal Pneumonia Vaccine. Side effects include pain and redness at the injection site, fever, and joint aches. Children are more likely to have fever within 48 hours if they receive other vaccines at the same time and also after the second dose. Rarely, such local reactions can be severe. Even if a person is mistakenly re-vaccinated before the effects of the first vaccination have worn off, the risk for severe side effects is very low. Allergic reactions are very rare.

Resources

• www.cdc.gov/flu -- U.S. Centers for Disease Control and Prevention
• www.niaid.nih.gov -- National Institute for Allergy and Infectious Diseases
• www.who.int/csr/disease/influenza -- World Health Organization
• www.cdc.gov/nip -- National Immunization Program
• www.immunize.org -- Immunization Action Coalition
• www.entnet.org -- American Academy of Otolaryngology-- Head and Neck Surgery
• www.cdc.gov/flu/avian -- Avian Influenza Information

References

Jefferson T, Demichelli V, Rivetti D, Jones M, Di Pietrantonj C, Rivetti A. Antivirals for influenza in healthy adults: systematic review. Lancet 2006 Jan 28;367(9507):303-13.

Centers for Disease Control. High levels of adamantane resistance among influenza A (H3N2) viruses and interim guidelines for use of antiviral agents--United States, 2005-06 influenza season. MMWR Morb Mortal Wkly Rep. 2006 Jan 20;55(2):44-6.

World Health Organization. Cumulative Number of Confirmed Human Cases of Avian Influenza A/(H5N1) Reported to WHO 25 January 2006.  Available at: http://www.who.int/csr/disease/avian_influenza/country/cases_table_2006_01_25/en/index.html. Accessed 1/25/06.

American Academy of Pediatrics Committee on Infectious Diseases. Recommended childhood and adolescent immunization schedule: United States, 2005. Pediatrics. 2005 Jan;115(1):182.

Harper SA, Fukuda K, Uyeki TM, Cox NJ, Bridges CB. Prevention and Control of Influenza: Recommendations of the Advisory Committee on Immunization Practices (ACIP).  MMWR Recomm Rep. 2005 Jul 29;54(RR-8):1-40.

Morantz CA. ACIP Updates Guidelines on Prevention and Control of Influenza. Am Fam Physician. 2005; 72(6); 1119-1127.

Langley JM. Prevention of influenza in the general population: Recommendation statement from the Canadian Task Force on Preventive Health Care. CMAJ. 2004; 171(10): 1213-22.

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