H1N1 Vaccine Trial in People with Asthma

(October 16, 2009) - When it comes to people with certain health conditions, the federal government is still trying to figure out what the correct dose of the new H1N1 vaccine should be. (Read about "Influenza") A new study is about to begin to try and decide what is needed for people with asthma. (Read about "Asthma") The National Institutes of Health 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 (Read about "The Immune System") in people with asthma, especially those with severe disease.

"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," says NIAID Director Anthony S. Fauci, MD. "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."

Individuals who already have been infected with 2009 H1N1 influenza or have received a 2009 H1N1 influenza vaccination will not be eligible for the study.

"The results of this study will have immediate implications for individuals with severe asthma as well as those who have milder asthma," says National Heart, Lung, and Blood Institute (NHLBI) Director Elizabeth G. Nabel, M.D.

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 Centers for Disease Control and Prevention (CDC) 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, health care providers and individuals with underlying chronic medical conditions, including asthma.

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.