A new study of a vaccine against rotavirus infection among African newborns shows the drug is highly effective against the disease, which can cause major gastrointestinal distress and death in babies and young children.
Last year, the World Health Organization (WHO) recommended that a vaccine be given to infants to prevent severe complications from rotavirus, which can cause potentially fatal diarrhea and dehydration. Malnourished babies or those infected with the AIDS virus are most at risk. Rotavirus kills a half million children worldwide each year, 230,000 of them in six of seven African countries with high rates of rotavirus infection.
A study, commissioned by the WHO and released Wednesday that evaluates the vaccine's effectiveness, prompted the health agency to recommend the vaccine for all infants.
Researchers with PATH - a global non-profit group specializing in vaccine research - found the vaccine called Rotarix reduced severe complications among groups of children in South Africa and Malawi by an average of 60 percent.
Study senior author Kathleen Neuzil of the Seattle, Washington-based non-profit is delighted with the results.
"This is very exciting. This is not a vaccine that needs to be developed," she said. "This is a vaccine that we have now that is used in many parts of the world and, again, has the potential to save millions of lives over the next 10 years or so. And rarely do you have interventions with that kind of impact."
Two vaccines, including Rotarix, are widely available in the developed world, preventing severe complications in about 95 percent of the rotavirus cases in the developed countries.
In the South African study, 3,100 infants in South Africa were vaccinated with Rotarix. Of these, 77 percent of them experienced mild complications compared to children who did not receive the vaccine.
Researchers in Malawi enrolled 1,700 infants and the vaccine reduced the frequency of severe rotavirus complications by 50 percent.
Neuzil says researchers don't know why Rotarix was less effective in Malawi.
They think it may be due to the fact that there's more malnutrition among Malawian children, which may interfere with the vaccine's effectiveness, or Neuzil says the children who received the vaccine in the study may be sicker than infants in South Africa.
"I think a remarkable finding of our study is that even though the efficacy was lower in the poorer countries, the amount of disease prevented was in fact higher because there is so much more severe disease in these countries," she said.
The WHO commissioned the study by Kathleen Neuzil and colleagues to gather data prior to the world body's recommendations.
The findings are published this week in The New England Journal of Medicine.