H1N1 Vaccine Safe and Induces Robust Immune Response in People with Asthma
Posted Dec 13 2010 4:00pm
Results from a government-sponsored clinical trial of inactivated 2009
H1N1 influenza vaccine in people with asthma indicate that a single dose
of vaccine was safe and induced a strong immune response predictive of
protection. The findings also suggest that individuals over the age of
60 who have severe asthma may require a larger dose of vaccine. The study
was cosponsored by the National Institute of Allergy and Infectious Diseases
(NIAID) and the National Heart, Lung, and Blood Institute (NHLBI), two
components of the National Institutes of Health, and appears online in
the Journal of Allergy and Clinical Immunology.
"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," says NIAID Director Anthony S.
Fauci, M.D. "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. This is important because
the H1N1 vaccine is one component of the seasonal influenza vaccine currently
being distributed for the 2010-2011 influenza season."
People with asthma are at risk for developing severe disease when infected
with the influenza virus. In addition, there is concern that the long
term use of corticosteroids, which are used to control asthma symptoms
and known to suppress the immune system, by people with severe asthma
might affect their ability to mount a healthy immune response to the
"This study shows patients and their doctors that it is safe and effective
to get the flu vaccination while they continue to take the corticosteroid
medications necessary to keep their asthma under control," says NHLBI
Acting Director Susan B. Shurin, M.D.
In late 2009, NIH rapidly designed and sponsored a clinical study to
determine the dose and number of doses of the 2009 H1N1 influenza vaccine
needed to safely produce a protective immune response in people with
asthma. NIH worked with the Department of Health and Human Services Biomedical
Advanced Research and Development Authority to acquire H1N1 vaccine for
the study from a U.S.-licensed influenza vaccine manufacturer. The trial
was conducted at NHLBI Severe Asthma Research Program (SARP) sites located
at university hospitals and centers throughout the United States.
The design of the trial was similar to that of other NIAID-sponsored
clinical trials of 2009 H1N1 influenza vaccines in healthy adults. In
these trials, a single dose of the vaccine containing 15 micrograms of
the influenza hemagglutinin molecule — the main target of the protective
antibody response — was found to be well tolerated and induced a strong
immune response in most participants.
The study enrolled 390 people aged 12 to 79 years with asthma. Participants
were divided into two groups based on the severity of their asthma. The
first group exhibited mild or moderate asthma, and the second group exhibited
severe asthma. For the purposes of the study, people with mild or moderate
asthma were characterized as needing no or low to moderate doses of inhaled
corticosteriods to control their disease symptoms. Those with severe
asthma needed high doses of inhaled corticosteriods and frequently required
oral corticosteriods to control their symptoms.
Half of the participants in each group received a 15-microgram dose
of vaccine, and the other half received a 30-microgram dose, both by
injection. Three weeks later, each participant received a second dose
in the same amount as the first dose. The vaccine, manufactured by Novartis
by methods used to prepare each years seasonal vaccine, contained inactivated
2009 H1N1 influenza virus and therefore could not cause influenza infection.
The investigators measured the level of antibodies against the 2009
H1N1 influenza virus in participants' blood samples, which were taken
three weeks after each injection, to assess the strength of the immune
The vaccine proved safe and effectively produced an immune response
indicative of protection. In participants with mild to moderate asthma,
and in most participants with severe asthma, a single 15-microgram dose
was sufficient to induce a presumably protective immune response. The
immune response after the first dose was not further improved after a
second dose, indicating that a single dose was adequate. Participants
older than age 60 with severe asthma had diminished immune responses
to the 15-microgram dose of vaccine, but the 30-microgram dose gave an
"We were not surprised that the older participants had less robust responses
to the vaccine compared with the younger participants because immune
system activity tends to decrease with age," says William Busse, M.D.,
a principal investigator of NHLBIs SARP and professor of medicine at
the University of Wisconsin in Madison. Based on these observations,
physicians may wish to consider immunizing older patients who have severe
asthma with the high-dose version of the 2010-2011 seasonal influenza
vaccine, which contains the 2009 H1N1 influenza virus component.
Safety data were collected and examined throughout the course of the
study by investigators and by an independent safety monitoring committee.
Participants were followed for any side effects they may have experienced
from the vaccine, as well as for asthma attacks that occurred during
the study. The vaccine did not exacerbate participants' asthma. In addition,
the vaccine was well-tolerated, and its safety profile was found to be
the same as that obtained in other studies in which the vaccine was given
to the general public.
NIAID conducts and supports research — at NIH, throughout the
United States, and worldwide — to study the causes of infectious and immune-mediated
diseases, and to develop better means of preventing, diagnosing and treating
these illnesses. News releases, fact sheets and other NIAID-related materials
are available on the NIAID Web site at http://www.niaid.nih.gov .
Part of the National Institutes of Health, the National Heart, Lung,
and Blood Institute (NHLBI) plans, conducts, and supports research related
to the causes, prevention, diagnosis, and treatment of heart, blood vessel,
lung, and blood diseases, and sleep disorders. The Institute also administers
national health education campaigns on women and heart disease, healthy
weight for children, and other topics. NHLBI press releases, information
on NHLBI's role in the American Recovery and Reinvestment Act, and other
materials are available online at www.nhlbi.nih.gov.
The National Institutes of Health (NIH) — The Nation's Medical
Research Agency — includes 27 Institutes and Centers and is
a component of the U.S. Department of Health and Human Services. It is
the primary federal agency for conducting and supporting basic, clinical
and translational medical research, and it investigates the causes, treatments,
and cures for both common and rare diseases. For more information about
NIH and its programs, visit www.nih.gov .
Reference: WW Busse et al. Vaccination of patients with
mild and severe asthma with a 2009 pandemic H1N1 influenza virus vaccine.
Journal of Allergy and Clinical Immunology. DOI: 0.1016/j.jaci.2010.11.014