Protection of infants against rotavirus diarrhoea by RIT 4237 attenuated bovine rotavirus strain vaccine.

A randomised, double-blind, placebo-controlled trial was conducted to evaluate the ability of RIT 4237 live attenuated bovine rotavirus (subgroup 1) vaccine strain to protect against natural rotavirus infection in children. 178 infants aged 8 to 11 months received a single oral dose of RIT 4237 vaccine or placebo and were followed up serologically and clinically during a subgroup 2 rotavirus epidemic. No side-effects attributable to the vaccine were observed. During the 5 months' observation after vaccination 2 of the 86 vaccine recipients and 18 of 92 placebo recipients had rotavirus diarrhoea lasting more than 24 h (p less than 0.001). The vaccine-protection rate was thus 88%. The 2 children in the vaccine group with rotavirus diarrhoea were regarded as primary vaccine failures since they had no detectable serum antibody responses after vaccination. Vaccine prepared from RIT 4237 strain of attenuated bovine rotavirus thus seems to protect children against heterologous subgroup 2 rotavirus diarrhoea.