TETRAVALENT RHESUS ROTAVIRUS VACCINE IN YOUNG INFANTS

A study of a tetravalent live oral rhesus rotavirus vaccine was conduc ted in 26 healthy infants 6-22 weeks of age to evaluate safety, viral shedding, and immunogenicity in a double-blind, placebo-controlled fas hion. The tetravalent rhesus rotavirus vaccine (RRV-TV) contained equa l amounts of RRV (serotype 3) and the VP7 reassortants DxRRV (serotype 1), DS1xRRV (serotype 2), and ST3xRRV (serotype 4). RRV-TV was highly infectious; 16 of 18 recipients shed virus. However, the recovered vi rus was almost exclusively the parent rhesus strain, RRV. Humoral immu ne responses were largely limited to the RRV strain. The most consiste nt response, seen in 14 of 18 vaccinees, was an ELISA IgM response to purified RRV. Mucosal antibody responses were not seen. The limited im mune response may be a function of age, presence of maternal antibody, timing of the convalescent specimens, or the polyvalent nature of the vaccine.