Merck's investigational rotavirus vaccine effectively protects infants against severe rotavirus disease
Merck & Co's investigational oral vaccine is 98 per cent effective in preventing severe forms of rotavirus infection, the most common cause of severe, dehydrating vomiting and diarrhea in infants, according to the results of the Rotavirus Efficacy and Safety Trial (REST), published in The New England Journal of medicine. The Merck investigational oral pentavalent vaccine contains five rotavirus strains (G1, G2, G3, G4 and P(8)). The G1, G2, G3 and G4 strains are responsible for approximately 95 per cent of rotavirus disease in Canada.
Rotavirus infection usually starts with fever, abdominal pain and vomiting, followed by diarrhea. These symptoms can be mild to severe and generally last for three to nine days with up to 20 episodes of diarrhea a day. Severe cases can lead to rapid dehydration, which could result in death if untreated.
REST is a double-blind, randomized, placebo-controlled study. It is one of the largest vaccine trials ever, with nearly 70,000 infants aged six to 12 weeks at enrolment from 11 countries: US, Finland, Sweden, Germany, Belgium, Italy, Mexico, Guatemala, Costa Rica, Jamaica and Taiwan. Merck designed this study to be large enough to provide a meaningful evaluation of efficacy and safety of its vaccine with respect to intussusception. Intussusception is a condition that can damage the intestine and that is associated with the use of a vaccine made by another manufacturer and previously licensed in the US. REST results showed that the incidence of intussusception was the same in both the vaccine and the placebo groups.
The REST results demonstrated that Merck's investigational oral pentavalent vaccine reduced rotavirus-related emergency room visits by 94 per cent, hospitalizations by 96 per cent and visits to the doctor by 86 per cent compared to placebo.
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