The Asthma-Influenza Connection

For some of us, influenza is an inconvenience that causes a fever and chills and keeps us in bed for a few days. For the approximately 11% of US citizens with asthma, however, the flu can lead to conditions that are much more severe. "Individuals with asthma are at high risk of developing complications after contracting the influenza virus," according to Dr. Randolph Lipchik, Professor of Medicine at the Medical College of Wisconsin, Division of Pulmonary and Critical Care Medicine. "When these individuals get an upper respiratory infection like influenza, they frequently have a flare-up of their asthma. Respiratory infections are more serious in patients with asthma, and can often lead to pneumonia and acute respiratory distress," he said.

That is why it is so critical for people who suffer from asthma to get a flu vaccination. "Vaccination is an effective way to prevent influenza," Dr. Lipchik said. Annual flu shots have been recommended for people 65 and older since the 1960s and for those 50 and older since 2000, but the message does not always reach its target audience. In fact, a study conducted by the Centers for Disease Control reveals that only one-third of all asthmatic adults and one-fifth of asthmatic adults under 50 years of age receive the flu vaccine annually. Data from the study, which was published in the September 2003 issue of Chest (the journal of the American College of Chest Physicians), was used to examine the prevalence of flu vaccinations among people who have asthma.

During the years of the study, 1999-2001, the following percentage of survey respondents with asthma reported that they received the flu vaccine: 35.1% (1999), 36.7% (2000), and 33.3% (2001). As study respondents with asthma aged, the number who were vaccinated increased, as indicated below:

• 18 to 49 years of age: 20.9% (1999), 22.7% (2000), and 21.1% (2001)
• 50 to 64 years of age: 46.2% (1999), 47.8% (2000), and 42.3% (2001)
• 65 years of age and older: 72.8% (1999), 71.2% (2000), and 64.8% (2001)

According to the survey, vaccination rates also increased among those respondents with higher education. Sex and ethnicity also affected vaccination rates. Of those respondents interviewed in 2000, fewer men than women and fewer African Americans than whites reported having been vaccinated. In 2001, fewer Hispanics than whites reported having been vaccinated.

Children Also Affected
It isn't just adults with asthma who are adversely affected by the influenza virus, but children as well. "A severe case of the flu can result in pneumonia, dehydration or a worsening of chronic medical conditions, and can be life-threatening - especially for the very old or the very young," Dr. Lipchik said. Influenza vaccine rates among children with asthma are particularly low (9% to 25%), according to the CDC study.

Further emphasizing the serious nature of influenza, reports indicate each year up to 40 million Americans develop the flu, and up to 200,000 are hospitalized. During past epidemics in the United States, influenza and its complications have caused between 10,000 and 40,000 deaths.

Prevention and Treatment Available
The best way to avoid the flu is to be vaccinated against it. (Unfortunately, periodic shortages due to production difficulties in recent years have made it difficult for some to receive the injected vaccine.) Injected influenza vaccination is recommended for anyone who wants it, except those who are allergic to eggs, Dr. Lipchik said. It is particularly recommended for people with asthma as well as the following conditions:

• All children ages 6 months to 23 months
• Women who will be pregnant during flu season
• People with chronic health problems including heart disease, diabetes and asthma
• People with suppressed immune systems

In June of 2003 the Food and Drug Administration approved FluMist, a flu vaccine that's sprayed into the nose, for healthy people between the ages of 5 and 49.

In addition, "Antiviral medications can be taken as treatment or prevention," Dr. Lipchik noted. "For example, if a family member has the flu, other family members can take the medication as a preventive measure. The newest medications on the market, TamifluŽ (oseltamivir) and RelenzaŽ (zanamivir), are active against both influenza A and B. Older medications, effective against influenza A, are rimantadine and amantadine.

Misinformation Abounds
Why don't more people get the flu vaccine, as recommended? A variety of reasons exist, including concern over side effects, financial barriers, and lack of awareness regarding the need for vaccination. Some people believe that the influenza vaccine can actually cause the flu, but this is not the case, Dr. Lipchik explained. "The injected flu vaccine is not a live virus - you cannot get the flu from it. You might get a sore arm and a mild fever, but that is all," he said. Injected flu vaccine is made from killed flu viruses, while FluMist contains live (but very weak) virus.

It is vital, according to Dr. Lipchik, that annual flu vaccination rates among people with asthma are increased. "The flu vaccine is safe and effective and all people who have asthma should be encouraged to get the flu vaccination as part of their routine care," he said.

JoAnn Petaschnick
HealthLink Contributing Writer

This article contains information from the 1999-2001 National Health Interview Surveys, National Center for Environmental Health, Centers for Disease Control and Prevention.