Influenza vaccination during pregnancy increased seroprotection in infants
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Most neonates have seroprotection against influenza if their mothers receive the vaccine any time during the second or third trimester but at least 15 days before delivery, according to recent study findings published in The Pediatric Infectious Disease Journal.
“This study shows that vaccination of pregnant women facilitates significant transplacental antibody transfer to babies for all strains of influenza virus contained in the 2010-2011 influenza vaccine,” the researchers wrote. “Less than one-third of neonates from non-immunized mothers had seroprotective titers compared to 85% among vaccinated women.”
The cross-sectional study included 188 women, of 101 received a non-adjuvanted influenza vaccine during their second or third trimester.
Researchers found that 84% to 86% of newborns of mothers who had been vaccinated showed seroprotective levels depending on the influenza strain compared with 29% to 33% of newborns whose mothers were not vaccinated (P<.001). Geometric mean titers in umbilical cord blood were increased to 17 times if the mother was vaccinated 2 or more weeks before delivery. However, vaccinated pregnant women just 2 to 4 weeks before delivery still offered more protection to the newborn compared with women who were not vaccinated.
“This study shows that influenza vaccination at any time during the second or third trimester of pregnancy, but at least 15 days before delivery, is an effective strategy to increase cord blood antibody titers and seroprotection rates in neonates,” the researchers wrote. “It is thus likely to reduce the risks of influenza infections during the first months of life.”
Disclosure: The researchers report no relevant financial disclosures.