Combined Effects of Antenatal Receipt of Influenza Vaccine by Mothers and Pneumococcal Conjugate Vaccine Receipt by Infants: Results from a Randomized, Blinded, Controlled Trial

A 2 × 2 factorial trial was performed to determine the efficacy of antennal influenza vaccination of mothers plus pneumococcal conjugate vaccination of their infants against respiratory illness during early infancy. The efficacy of trivalent inactivated influenza vaccine (TIV; delivered to mothers) plus 7-valent pneumococcal vaccine (PCV7; delivered to infants) was higher than the efficacy of TIV alone or PCV7 alone. During the period of the study in which influenza was circulating, the efficacy of TIV plus PCV7 was 72.4% (95% confidence interval, 30.2%-89.1%) against febrile respiratory illness and 66.4% (95% CI, 14.3%-86.9%) against medically attended acute respiratory illness.