Pneumococcal Nasopharyngeal Carriage in Infants of Mothers Immunized with 23V Non-conjugate Pneumococcal Polysaccharide Vaccine

To assess the effects of maternal immunization on pneumococcal colonization in infants, pregnant women were assigned into three groups. The group Pregn Vac received the Pn23V during pregnancy, the group Puerp Vac received vaccine during immediate puerperium and the group No Vac received no vaccine. Nasopharyngeal samples were collected at 3 and 6 months. A total of 150 pregnant women were selected during the prenatal period. The proportion of pneumococcal carriage in at least one evaluation was in group Pregn Vac 22.2% (10/45), group Puerp Vac 23.4% (11/47) and group No Vac 21.2% (10/47), respectively. The most frequently isolated serotype in group Puerp Va and group No Vac was 6B and 6A. In the Pregn Vac, the most important serotype was 19F. Although this study was unable to demonstrate any effect of maternal vaccination in reducing pneumococcal colonization, reduction of colonization for serotype 6B in infants may be an important effect.