NIH announces government-sponsored clinical trial of H1N1 vaccine

WASHINGTON The National Institutes of Health on Friday announced that it is preparing to launch the first government-sponsored clinical trial to determine what dose of the 2009 H1N1 influenza vaccine is needed to induce a protective immune response in people with asthma, especially those with severe disease.

The Centers for Disease Control and Prevention has recommended that certain at-risk populations receive the new H1N1 vaccine as a priority before the general population. These target populations include pregnant women, healthcare providers and individuals with underlying chronic medical conditions, including asthma.

“People with severe asthma often take high doses of glucocorticoids that can suppress their immune system, placing them at greater risk for infection and possibly serious disease caused by 2009 H1N1 influenza virus,” stated Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases. “We need to determine the optimal dose of 2009 H1N1 influenza vaccine that can be safely administered to this at-risk population and whether one or two doses are needed to produce an immune response that is predictive of protection.”

People who have severe asthma may be particularly at risk for infection with the 2009 H1N1 influenza virus. A report published in 2004 suggested that some people who took high doses of glucocorticoids to treat their asthma may receive less protection from influenza vaccines against some strains of influenza. Early in the 2009 H1N1 flu outbreak a CDC review of hospital records found that people with asthma have a four-fold increased risk of being hospitalized with infection compared to the general population.

Early results from other clinical trials of 2009 H1N1 influenza vaccines in healthy adults have shown that a single 15-microgram dose of 2009 H1N1 influenza vaccine without adjuvant is well-tolerated and induces a strong immune response in most participants. The same vaccine also generates an immune response that is expected to be protective in healthy children ages 10 to 17 years. Ongoing trials are comparing the immune response to one and two doses of 15- or 30-micrograms of vaccine given three weeks apart in various populations.

The study is being cosponsored by the NIAID and the National Heart, Lung, and Blood Institute, both part of NIH.