H1N1 influenza vaccine safe, effective in people with asthma

Busse WW. J Allergy Clin Immunol. 2010;doi:10.1016/j.jaci.2010.11.014.

Inactivated 2009 H1N1 influenza vaccine was safe and induced a strong immune response in people with asthma, according to results from a government-sponsored clinical trial that appears online in the Journal of Allergy and Clinical Immunology.

Data from the trial, which was co-sponsored by the National Institute of Allergy and Infectious Diseases and the National Heart, Lung, and Blood Institute, also suggest that individuals aged older than 60 years may require a larger dose of the vaccine if they have severe asthma.

“Asthma was the most common underlying health condition among those hospitalized in the United States with 2009 H1N1 influenza infection during the 2009-2010 influenza season,” NIAID director Anthony S. Fauci, MD, said in a press release. “The results of this clinical trial show that the 2009 H1N1 influenza vaccine was safe and led to adequate production of antibodies thought to be protective against the virus.”

The influenza virus puts those with asthma at risk for developing severe disease. Also, long-term use of corticosteroids poses a concern for people with asthma, as the use of these drugs suppresses the immune system and may affect the patient’s ability to mount a healthy immune response to the vaccine.

The trial included 390 participants with asthma, aged 12 to 79 years. They were divided by the severity of their asthma — mild or moderate asthma and severe asthma. Mild to moderate asthma was defined as those who needed no or low doses of inhaled corticosteroids. Severe asthma was defined as those who needed high doses of inhaled corticosteroids.

Half of the patients in each group received a 15-mcg dose of the vaccine, and the other half received a 30-mcg dose. Three weeks later, all participants received a second dose that was the same amount as their first dose. The investigators evaluated blood samples to assess the immune response.

The 15-mcg dose induced a protective immune response in participants with mild to moderate asthma and most participants with severe asthma. The immune response after the first dose was not improved with a second dose, which indicates that only one dose is needed. In participants aged older than 60 years with severe asthma, the 30-mcg dose provided an adequate immune response.

The vaccine was well tolerated and did not exacerbate participants’ asthma.

Dr. Anthony S. Fauci has no direct financial interest in any of the products mentioned in this article nor is he a paid consultant for any companies mentioned.

There have been previous studies of trivalent influenza (TIV) vaccine in patients with asthma, all of which showed that TIV could be given safely. However, that has not been the case with the live attenuated vaccine, and it is contraindicated in children with asthma. Add to that the fact that asthma was a very significant underlying condition in persons hospitalized with severe influenza during the 2009 H1N1 pandemic. Therefore, it was important to do this study, which clearly showed that the pandemic H1N1 was both safe and immunogenic in children and adults with asthma. This should be reassuring to both patients and providers since the pandemic H1N1 strain is one of the components in this year’s trivalent inactivated vaccine.

—Theodore C. Eickhoff, MD
Infectious Diseases in Children Editorial Board member

Disclosure: Dr. Theodore C. Eickhoff has no direct financial interest in any of the products mentioned in this article nor is he a paid consultant for any companies mentioned.

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