IMMUNE PROTECTION OF INFANTS AGAINST ROTAVIRUS GASTROENTERITIS BY A SEROTYPE-1 REASSORTANT OF BOVINE ROTAVIRUS WC3

The safety and protective efficacy of a serotype 1 reassortant of bovine rotavirus WC3, designated strainWI79-9, was evaluated in a double-blind placebo-controlled trial. Rotavirus reassor tantWI79-9 contains a gene segment 9 coding for the surface structural protein vp7 of a human serotype 1 rotavirus, with all other gene segments derived from WC3 rotavirus, which had previously been shown to be safe and immunogenic in infants. Infants 2-11 months of age were given two doses of vaccine (107,3 plaque-forming units/dose) or of placebo 28 days apart. Adverse reactions to the vaccine were not detected. The incidence of serum plaque reduction neutralization antibody responses to two doses of vaccine wasserotype 6, 97%; serotype 3, 68%; and serotype 1, 22%. Active surveillance during the subsequent rotavirus season revealed 8 cases of rotavirus gastroenteritis in 39 placebo control infants and no cases in 38 WI79-9 vaccine recipients (protection = 100%, P =.003). Six cases of rotavirus gastroenteritis were caused by type 1 and two by type 3 virus. Although vaccination with WI79-9 affected only the incidence of rotavirus gastroenteritis, the vaccinated infants exhibited a significantly reduced incidence of total days of diarrhea, fever, and illness associated with gastroenteritis in general. © 1990, University of Chicago. All rights reserved.