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| |  Rotavirus Vaccine Trials Successful in Asia and Africa, Should Be Rolled Out in Both Continents NEW YORK -- August 5, 2010 -- Studies in Asia and Africa have shown that a rotavirus vaccine is safe and effective in preventing severe rotavirus gastroenteritis (severe RVG), which is responsible for more than half a million child deaths worldwide. The authors of these 2 studies, published online first in The Lancet, have now added their voices to those of the World Health Organization (WHO) and other international experts, calling for the roll-out of the vaccine across both continents. In the first study, John C. Victor, MD, PATH, Seattle, Washington, and colleagues carried out a randomised controlled trial in rural Matlab, Bangladesh and in an urban and semi-urban part of Vietnam. The study is the first clinical efficacy trial of an already licensed rotavirus vaccine in developing countries in Asia. A total of 2,036 infants aged 4 to 12 weeks without symptoms of gastrointestinal disorders were randomly assigned in a 1:1 ratio to receive 3 oral doses of the pentavalent rotavirus vaccine or placebo at around 6 weeks, 10 weeks, and 14 weeks of age, in conjunction with routine infant vaccines including oral poliovirus vaccine. Over nearly 2 years of follow-up, the researchers recorded 38 cases of severe RVG in the vaccine group, compared with 71 in the placebo group, giving a calculated vaccine efficacy of 48%. Rates of serious adverse events were low in both the vaccine (2.5%) and placebo (2.0%) groups, with no serious adverse event considered linked to receipt of the intervention. Despite this efficacy being lower than demonstrated in trials in high-income countries, the authors of both studies believe use of the vaccine could save many thousands of lives across both continents. "Our main goal is to prevent the most severe disease that might lead to death in areas where treatment is inaccessible," said Dr. Victor. "Because we saw indications that the vaccine is even more efficacious in preventing the most severe disease children experience, I am very optimistic about the impact that rotavirus vaccines will have on mortality in these settings."
"With a WHO recommendation for rotavirus vaccines now in place, governments of developing countries in Africa and Asia are deciding how to prioritise introduction of rotavirus vaccine in their public health agendas," he said. "Our trial shows that a live oral rotavirus vaccine has the potential to halve the incidence of severe rotavirus gastroenteritis in developing populations in Asia. Alongside efficacy results for this vaccine in Africa, our study supports WHO's strong recommendation for expansion of rotavirus vaccine use to the poorest nations in Africa and Asia. Rotavirus vaccines have the potential to protect the lives of nearly 2 million children in the next decade alone." In the second paper, George E. Armah, MD, University of Ghana, Accra, Ghana, and Kathleen M. Neuzil, PATH, and colleagues analysed the effects of the same vaccine in Africa, where some 240,000 rotavirus-related deaths occur annually. The researchers carried out a randomised controlled trial of the vaccine in Ghana, Kenya, and Mali. In this study, 5,468 children aged 4 to 12 weeks without symptoms of gastrointestinal disorders were randomly assigned in a 1:1 ratio to receive 3 oral doses of the same vaccine as the other study or placebo at around 6 weeks, 10 weeks, and 14 weeks of age. Infants with HIV infection were not excluded. The researchers recorded 79 cases of severe RVG in the vaccine group, compared with 129 in the placebo group, giving a vaccine efficacy of 39%. Rates of serious adverse events were again low in both the vaccine (1.5%) and placebo (1.7%) groups, with the most common reported event being gastroenteritis. "The vaccine provided significant protection against severe rotavirus gastroenteritis in infants for nearly 2 years of follow-up," the authors wrote. 'This protection was especially high through the first year of life (64.2% vaccine efficacy), when the disease burden, including mortality, is highest." "In Africa, where young children are dying from diarrhoeal disease and prompt medical care is often out of reach, the need to prevent rotavirus is especially urgent. Introduction of rotavirus vaccines for African children, along with imminent introduction of pneumococcal and meningococcal conjugate vaccines in parts of Africa, could instigate a new era of reduction of childhood disease and mortality."
SOURCE: The Lancet
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