Vaccines in pregnancy, with the actual numbers
Three, with genuinely different strengths of evidence.
Tdap, for whooping cough. In a cohort of 148,981 newborns, maternal Tdap was 91.4% effective at preventing pertussis in the first two months of life and 69.0% effective across the first year. The first two months are the point, because that is before a baby can be vaccinated.
Influenza. In 3,764 infants under six months across 7 US centres, maternal vaccination was 34% effective against flu-related hospital or emergency visits, 53% in infants under three months. Third-trimester vaccination was 52% effective; first or second trimester vaccination showed no significant effect.
RSV. In a randomized trial of 7,358 pregnant women, medically attended severe RSV lower respiratory illness in the first 90 days occurred in 6 infants of vaccinated mothers against 33 of unvaccinated, an efficacy of 81.8%. At 180 days it was 19 against 62, an efficacy of 69.4%. The wider endpoint of any RSV illness did not meet its statistical target.