Newborns can be protected from seasonal flu when their
mothers are vaccinated during
pregnancy, according to a study led by researchers at the
Johns Hopkins Bloomberg
School of Public Health.
The researchers observed a 63 percent reduction in
proven influenza illness among infants born
to vaccinated mothers, while the number of serious
respiratory illnesses to both mothers and infants
dropped by 36 percent. The study is the first to
demonstrate that the inactivated influenza vaccine
provides protection to both mother and newborn. The
findings were presented Sept. 17 during the
National Vaccine Advisory Committee meeting in Washington,
D.C., and will be published in the Oct. 9
issue of the New England Journal of Medicine.
The inactivated influenza vaccine (the flu shot) is
not licensed for infants younger than 6
months. The nasal flu vaccine is not available for children
under age 2. The flu shot has been
recommended for pregnant women in the United States since
1997, and approximately 15 percent of
pregnant women are vaccinated each year.
"Even though there is no flu vaccine for these
children, our study shows that a newborn's risk of
infection can be greatly reduced by vaccinating mom during
pregnancy. It's a two-for-one benefit,"
said Mark Steinhoff, the study's senior author and a
professor in the Bloomberg School's Department
of International Health. "Infants under 6 months have
the highest rates of hospitalization from
influenza among children in the U.S. These admission rates
are higher than those for the elderly and
other high-risk adult groups."
The study was conducted in Bangladesh in collaboration
with researchers from the International
Centre for Diarrhoeal Disease Research, known as ICDDR,B.
Researchers observed 340 mothers and
their infants as part of the larger Mother's Gift vaccine
evaluation study. The mothers were randomly
selected to receive either flu vaccine or pneumococcal
"Pregnant woman should be encouraged to be vaccinated
for the flu to protect their infants and
themselves," Steinhoff said.
Additional authors of the study are K. Zaman, S.E.
Arifeen, M. Rahman, R. Raqui, N. Shahid and
R.F. Breiman, all of the International Centre for
Diarrhoeal Disease Research in Bangladesh; E. Wilson,
Bloomberg School of Public Health; and S.B. Omer, Emory
The research was supported by the Bill & Melinda Gates
Foundation, United States Agency for
International Development, the NPVO Research Fund, Wyeth
Pharmaceuticals, the Thrasher Research
Fund, Aventis Pasteur, ICDDR,B and the Johns Hopkins
Bloomberg School of Public Health.