Results from a national H1N1 pandemic influenza vaccine study that looked at the high risk population group of asthmatics found that the 2009 vaccine -- which is currently a component of the 2010 influenza vaccine – was safe to administer to adult and adolescent patients with asthma.
The study, which appears online in the Journal of Allergy and Clinical Immunology , showed that adult and adolescent asthmatics developed a protective immune response to the H1N1 virus at a rate comparable to healthy individuals. A single 15-microgram dose led to protective antibody levels in most asthma patients with the exception of adults older than 60 with severe asthma who responded better to a higher, 30-microgram dose.
About 80 local asthma patients participated in the study due to their enrollment in the Severe Asthma Research Program (SARP), a multicenter network studying clinical and biologic features of severe asthma. The Center for Genomics and Personalized Medicine Research at Wake Forest University Baptist Medical Center is one of four centers participating in the SARP across the United States.
The purpose of the study was to determine the safety of the 2009 H1N1 influenza vaccine in people with asthma and the dose needed to induce a protective immune response in these patients, especially those with severe asthma.
The National Institute of Allergy and Infectious Diseases (NIAID) and National Heart, Lung and Blood Institute (NHLBI), both components of the National Institutes of Health, funded the study, which was conducted through NHLBI’s SARP network.
Early in the H1N1 epidemic, the Centers for Disease Control and Prevention (CDC) identified patients with asthma as a priority group for vaccination because asthma was the most common co-morbidity in people hospitalized due to influenza. A CDC review of hospital records found that people with asthma had a four-fold increased risk of being hospitalized with infection compared to the general population.
“It was not surprising that influenza infection might occur more often and be more serious in patients with asthma given that viral respiratory infections are believed to be a major cause of asthma problems,” said Eugene Bleecker, M.D., the principal investigator of the trial at Wake Forest Baptist.
Wake Forest Baptist and the other participating sites were chosen because of their involvement with the SARP network, which already had a well-characterized group of participants with mild, moderate and severe asthma who were eligible for this study. These groups were largely distinguished by the amount and frequency of inhaled corticosteroids needed to control asthma symptoms, ranging from those with very mild asthma who did not require inhaled corticosteroids to patients with severe asthma who need higher doses of inhaled corticosteroids and frequently oral corticosteroids as well.
“We were very excited that our participants were able to take part in this trial,” said Wendy Moore, M.D., a Wake Forest Baptist pulmonologist involved in the trial. “We were able to offer them vaccination early in the H1N1 epidemic when flu shots were difficult to find. It was a win-win situation for both us and our patients.”
The randomized study looked at two different doses of vaccine given to people with mild to moderate asthma or severe asthma. Half of the participants in each group received the standard 15-microgram dose of vaccine which was the same dose given to the general public, while the other half in each group received a higher, 30-microgram dose of vaccine. Three weeks later, each participant received a second dose of the same amount. The strength of the immune response induced by the vaccine was determined in blood samples by measuring the level of antibodies against 2009 H1N1 flu virus. Most participants had an adequate immune response to the vaccine after one dose, negating the need for a second “booster” dose weeks later. Older participants with severe asthma responded better to the higher 30-microgram vaccine dose suggesting that this group might benefit from higher doses of influenza vaccine such as is available in the seasonal influenza vaccine this year.
The Center for Genomics and Personalized Medicine Research is a research initiative to identify genes that contribute to common human diseases and determine how these genes interact with environmental risk factors. The center also facilitates the development of novel therapeutic regimes and investigates interactions between genes and therapeutic responses to drug therapy. The center’s research priorities include pulmonary disease, cardiovascular disease, diabetes and prostate cancer.
The NIH has supported basic influenza research to better understand how influenza viruses replicate, interact with their hosts, stimulate and evade immune responses, and evolve into new strains. Results from these studies are used to design new therapies, diagnostics and vaccines.
Detailed information about this study can be found at the SARP web site (http://severeasthma.org/).