Fig 1. Body weight changes in the offspring within 21 days after the lethal virus challenge.

A). Both mothers and offspring were immunized with the inactivated vaccine through the IP route. B). Mothers were immunized through the IP route and offspring through the IN route. C). Both mothers and offspring were immunized through the IN route. D). Mothers were immunized through the IN route and offspring through the IP route. Data points represent the means ± SD of each group of mice. “MDA- control” indicates that the offspring in this group had no MDAs and were unimmunized; “1μg MDA+” indicates that the offspring in this group had MDAs and were immunized with 1 μg of the vaccine.