Oral rotavirus vaccination in breast- and bottle-fed infants aged 6 to 12 months.

Oral bovine rotavirus vaccine RIT 4237 was tested at two dose levels in 217 children between 6 and 12 months of age who received either breast milk or bottle milk (cow's milk or infant formula) before vaccination. Of the children 65% were initially seronegative for rotavirus ELISA IgG and IgM antibody. The full vaccine dose (10(8.3) 50% tissue culture infective doses, TCID50) induced seroconversion rates 81% and 86% and booster response rates 69% and 64% in breast and bottle-fed children, respectively. There was no difference in the vaccine response of infants receiving cow's milk or infant formula either. It is concluded that the RIT 4237 rotavirus vaccine at the dose level 10(8.3) TCID50 gives a satisfactory response in both breast- and bottle-fed children in this age group, but multiple vaccinations may be needed for maximal efficacy.