Register for Initial Results Show Pregnant Women Mount Strong Immune Response to One Dose of 2009 H1N1 Flu Vaccine
Monday, November 2, 2009
NIAID Office of Communications
301-402-1663
Healthy pregnant women mount a robust immune response following just one dose of
2009 H1N1 influenza vaccine, according to initial results from an ongoing
clinical trial sponsored by the National Institute of Allergy and Infectious
Diseases (NIAID) of the National Institutes of Health.
"For pregnant women, who are among the most vulnerable to serious health
problems from 2009 H1N1 infection, these initial results are very reassuring,"
says NIAID Director Anthony S. Fauci, M.D. "The immune responses seen in these
healthy pregnant women are comparable to those seen in healthy adults at the
same time point after a single vaccination, and the vaccine has been well
tolerated."
According to the Centers for Disease Control and Prevention, since the outbreak
began last spring, at least 100 pregnant women have been hospitalized in
intensive care units in the United States and at the last official count, 28
pregnant women have died.
A preliminary analysis of blood samples taken 21 days post-vaccination from a
subgroup of 50 pregnant women participating in the trial shows the following:
- In 25 women who received a single 15-microgram dose of the vaccine, the H1N1 flu vaccine elicited an immune response likely to be protective in 92 percent, or 23 of 25, of these women.
- In 25 women who received a single 30-microgram dose of the vaccine, the H1N1 flu vaccine elicited an immune response likely to be protective in 96 percent, or 24 of 25, of these women.
The trial began on Sept. 9 and reached its target enrollment of 120
volunteers in mid-October. All participants are between 18 to 39 years old and
began the study in their second or third trimester (14 to 34 weeks) of
pregnancy. At entry into the study, the participants were divided at random into
two groups: half are receiving two doses of a 15-microgram vaccine and the other
half are receiving two doses of a 30-microgram vaccine. The two injections of
vaccine are spaced three weeks apart.
Safety is being monitored closely in the trial, by the study investigators and
by an independent panel of experts known as a safety monitoring committee. To
date, the vaccine appears to be well-tolerated, and no safety concerns related
to the vaccine have arisen.
The vaccine used in this clinical trial was manufactured by Sanofi Pasteur in
its plant in Swiftwater, Pa., in the same manner as the company’s injectable
seasonal influenza vaccine. Like the seasonal flu vaccine, the 2009 H1N1 flu
vaccine contains a purified portion of the killed virus and therefore cannot
cause infection. The vaccine does not contain the preservative thimerosal or an
immune boosting substance known as an adjuvant.
NIAID is conducting this trial through five clinical sites affiliated with its
longstanding clinical trials network known as the Vaccine and Treatment
Evaluation Units. For additional information about the NIAID trial in healthy
pregnant women, see the Sept. 9 NIAID news release
http://www3.niaid.nih.gov/news/newsreleases/2009/H1N1pregnanttrials.htm and
related Q&A
http://www3.niaid.nih.gov/news/QA/H1N1pregnanttrials.htm
For more information on influenza, including pandemic influenza and avian
influenza, visit www.flu.gov Also see
NIAID's influenza Web portal at
http://www3.niaid.nih.gov/topics/Flu/
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
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
