Reactogenicity and immunogenicity of rotavirus WC3 vaccine in 5-12-month old infants

Summary Rotavirus is a major cause of acute gastroenteritis in infants worldwide and there is need for an effective vaccine. Rotavirus Wistar calf 3 (WC3) is a strain of bovine origin attenuated by 12 passages in cell culture. A lyophilized candidate vaccine containing 1 × 10 7 PFU of WC3 has been developed. An oral dose was given to 25 French infants 5–12-months old (mean age 8.6 months). No diarrhoea was observed within 2 weeks after vaccination. Unexplained vomiting was reported once and isolated fever > 37.8°C was reported 3 times during the first week. One month later, a neutralizing antibody response to serotypes tested was shown in 88 % of cases, with heterotypic responses to human serotype 3 (SA11 strain) in 72 % and to type 1 (WA strain) in 48 %. The percentage of immune response was similar whether the infant had antibody prior to immunization or not, but a booster effect was observed in children who had pre-immunization rotavirus antibodies. Considering these promising results, efficacy trials are in the planning in different parts of the world.