Maternal vaccination against influenza associated with protection for infants

http://www.eurekalert.org/pub_releases/2016-07/tjnj-mva063016.php

Public Release: 5-Jul-2016
Maternal vaccination again influenza associated with protection for infants
The JAMA Network Journals

How long does the protection from a mother's immunization against influenza during pregnancy last for infants after they are born?

Marta C. Nunes, Ph.D., of the University of the Witwatersrand, Johannesburg, South Africa, and coauthors sought to answer that questions in an article published online by JAMA Pediatrics. It's an important question because the incidence of influenza among infants is high and illness can cause hospitalizations and death. Also, current vaccines don't work well in infants less than 6 months of age and are not licensed for use in that age group.

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Analysis of the vaccine's efficacy included 1,026 infants born to women immunized with IIV3 and 1,023 infants born to women given placebo. The vaccine's efficacy against influenza illness was highest when infants were 8 weeks or younger at 85.6 percent but decreased as the infants grew to 25.5 percent among infants 8 to 16 weeks and to 30.3 percent among infants 16 to 24 weeks, according to the results.

Additionally, in a subset of infants, the percentage of infants with antibodies at or above a certain level dropped from 56 percent in the first week of life to less than 10 percent at 24 weeks of age.

tudy limitations include that the same IIV3 formulation was used in both study years.

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