Malaria chemosuppression during pregnancy. IV. Its effects on the newborn's passive malaria immunity.

The effect of malaria prophylaxis during pregnancy on the levels of cord blood anti-sporozoite antibodies was investigated in 203 newborns in Muheza, Tanzania. Mothers of 76 newborns had received prophylaxis with proguanil daily (PROG), 66 chloroquine once weekly (CQ), and 61 got a combination of the two drugs (CQ+PROG). Prophylaxis with PROG or CQ+PROG was more efficacious than with CQ. The mean antibody titres were comparable in all three groups, despite titres being significantly low in mothers of the CQ+PROG group. In 93% of 167 paired maternal-cord sera, maternal titres were higher than cord titres. The correlation between maternal and cord titres was low. Parity, placental malaria, and baby maturity showed little influence on titres. Titres of babies delivered by Caesarean section or whose placenta weighed between 0.75 and 1 kg were comparatively low. The first occurrence of a malaria parasitaemia in infants was independent of the levels of cord titres at birth. The results suggested that chemoprophylaxis as effective as PROG or CQ+PROG in holoendemic areas, insignificantly affects maternal-foetal transfer of anti-sporozoite antibodies, and that levels of these antibodies at birth do not modulate the first occurrence of infancy malaria parasitaemia. Interference with the maternal-foetal transfer of this antibody and possibly other component antibodies of passive immunity should not limit the selection of PROG or CQ+PROG for chemoprophylaxis.