Protective Effect of WC3 Vaccine Against Rotavirus Diarrhea in Infants During a Predominantly Serotype 1 Rotavirus Season

Abstract

We used a double-blind, placebo-controlled trial to study the efficacy of WC3 rotavirus vaccine administered to 104 infants (ages, three to 12 months) before the rotavirus season. Forty-nine infants received vaccine; 55 received placebo. Rotavirus disease during this season was predominantly caused by a serotype 1 strain. In placebo recipients there were 14 cases of rotavirus diarrhea (attack rate, 25%); 11 were moderate to severe (attack rate, 20%). Vaccinees experienced only three cases of rotavirus disease (attack rate, 6.1%), all mild. When all cases (whether associated with rotavirus or not) of clinically significant diarrhea (CSD) were evaluated, WC3 vaccine provided statistically significant (P less than .01) protection against the total number of episodes of CSD and reduced the number of days of CSD-associated diarrhea, vomiting, fever, or illness. Seventy-one percent of the WC3-vaccinated infants had serum antibody responses to the vaccine. The 14 placebo recipients who experienced natural disease predominantly had antibody responses to serotype 1. Sera taken after the rotavirus season revealed a nearly identical rate (40%) of natural rotavirus infection in the vaccinated and placebo groups.

Assessment of the Epidemic Potential of a New Strain of Rotavirus Associated with the Novel G9 Serotype Which Caused an Outbreak in the United States for the First Time in the 1995-1996 Season

“…To assess whether patients with G9 versus patients with non-G9 strains differed in disease severity or by age at presentation, we examined all available patient records from the 1995-1996 season to collect standard information on the patient's duration and severity of diarrhea, vomiting, fever, and malaise, factors which were then scored on a scale of severity from 2 to 24 as described previously (2). These observations were also compared to those of the first 24 rotavirus disease cases identified in the previous and immediately subsequent rotavirus seasons.…”

Human milk mucin inhibits rotavirus replication and prevents experimental gastroenteritis.

“…The recognition ofthe importance of rotaviral infections has led to a substantial effort directed at the prevention ofinfection by means ofactive immunization. However, current vaccine regimens have displayed variable degrees of efficacy, indicating the need for the better understanding of the mechanisms responsible for disease prevention (5,(13)(14)(15)(16)(17).…”

Rotavirus vaccines: Opportunities and challenges

“…The first rotavirus vaccines were based upon single rotavirus strains from either bovine (WC3; G6P [5] and RIT4237; G6P [1]) 87,88 or rhesus (RRV; G3P [4]) 89 origins following observations that infection of laboratory animals with animal rotaviruses protected against subsequent challenge with a human strain. After showing initial promise, these vaccines were abandoned after field trials provided highly variable results in several different countries.…”