Mothers-to-be impart antibodies to offspring that pay dividends later
A pregnant woman who gets a flu shot passes protection on to her fetus that lessens the newborn’s likelihood of contracting the flu during the first months of life, researchers report in the Oct. 9 New England Journal of Medicine.
Although the vaccine has been shown to be safe, no randomized trial has evaluated the shot’s effectiveness in a clinical setting — until now.
“I think this will now make a difference,” says study
coauthor Mark Steinhoff, a pediatrician at
Vaccinating pregnant women against influenza is approved and
even recommended by
“Pregnant women are generally healthy, and healthy people
often don’t seek out preventive measures like vaccinations,” says Lisa Jackson,
an internist and vaccine researcher at the
Flu is dangerous to newborns. In some years, fully 1 percent
of all newborns under age 6 months in the
In the new study, Steinhoff and his team recruited 340
pregnant women in
After the women gave birth, weekly visits to clinics revealed that six infants whose mothers had received flu shots developed a diagnosed case of the flu during their first six months, whereas 16 babies born to the other mothers did.
The babies whose mothers got flu shots also were roughly one-third less likely to contract a nonspecific respiratory infection accompanied by a fever — illnesses that were probably undiagnosed influenza, Steinhoff says.
When vaccinated, a pregnant woman makes antibodies against the flu virus and passes some of them along to her fetus. The new data suggest that these antibodies provide a grace period for a newborn until they wear off months later, Steinhoff says.
“This certainly does suggest there’s a benefit to flu shots
during pregnancy,” says
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