EFFECT OF BREAST-FEEDING ON THE TAKE OF RIT 4237 ORAL ROTAVIRUS VACCINE

Abstract

Oral vaccination with a live attenuated bovine rotavirus vaccine strain RIT 4237 induces cross-protection against human rotavirus diarrhoea ( Vesikari et al, Lancet i:977, 1984). Oral rotavirus vaccine is sensitive to gastric acid and should therefore be adminestered with an acid neutralizing substance such as milk. Vaccination at the time of breast feeding would be simple and logical in young infants, but breast milk might have antibodies and nonspecific factors that prevent the take of the vaccine. 48 breast-fed and 58 bottle-fed (cow's milk or formula) infants aged 6 to 12 months received 108.3 tissue culture infective doses of the RIT 4237 vaccine immediately after feeding. Serum specimens were collected before and 1 month after vaccination. Seven of the bottle-fed but none of the breast-fed infants had rotavirus IgM antibody before vaccination. Seroconversion by rotavirus ELISA-IgM antibodies was observed in 36/48 (75%) of the breast-fed and 38/51 (75%) of the bottle-fed infants. The IgG seroconversion rate was somewhat lower in the breast-fed (50%) than in the bottle-fed (69%) group. Thus in this age group breast-feeding did not inhibit the vaccine take, but possibly modified the antibody response. Altogether the serological responses were regarded as satisfactory, since it is known that the clinical protection rate against rotavirus diarrhoea is better than the serological response rate. The effect of colostrum on rotavirus vaccination is now being studied.