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Clinical trials help answer questions about how a vaccine will work.

Partners collaborate to find out how vaccine will work in different settings

By the mid-2000s, two vaccines against the most common cause of severe diarrhea—rotavirus—were nearing introduction in the US market. RotaTeq from Merck & Co., Inc., and Rotarix from GlaxoSmithKline (GSK) Biologicals were being tested in Europe, Latin America, and the United States.

But questions remained about how they would behave in poor settings, where ongoing illness and malnutrition can compromise the effectiveness of oral vaccines like these. The fate of an earlier rotavirus vaccine that had been pulled from the US market also gave health officials in developing countries pause. The World Health Organization, meanwhile, signaled that it would need evidence showing how the vaccines performed in developing countries before it would recommend children there receive them. The Rotavirus Vaccine Program (RVP) partners would have to prove that a vaccine would be safe for young children in the world’s poorest countries, not just those in the richest.

We enrolled 10,000 children in clinical trials that eventually demonstrated rotavirus vaccine's lifesaving potential.

In an effort to build evidence, the partners worked closely with Merck and GSK to launch rigorous clinical trials in Africa and Asia. We needed to know how many doses of vaccine children needed, how it acted in children with HIV, if it provided protection in infants, and if it could be administered with another oral vaccine commonly given in childhood, the polio vaccine. RVP carefully designed the trials to answer these questions, and then worked with governments in seven countries to establish trial sites. Between 2004 and 2008, we enrolled 10,000 children in trials that eventually demonstrated the vaccines’ lifesaving potential.

Trouble builds in Nicaragua

Meanwhile, a crisis was growing in Nicaragua. Rotavirus was spreading across the country, creating a diarrhea outbreak in 2005 that sent hundreds of children to hospitals and taxed Nicaragua’s public health system. The US Centers for Disease Control and Prevention was dispatched to determine the cause of the outbreak, and Nicaraguan health officials, knowing of our work on a vaccine, contacted PATH.

Still from 'A Common Disease, A Promising Solution' video.

Follow the trail of rotavirus vaccines as they prevent deadly diarrheal disease in Nicaragua. Watch the video.

We and our partners tapped into our close partnerships with the Nicaraguan Ministry of Health, the Pan American Health Organization, and child health experts to devise a strategy that would help the country build awareness of rotavirus vaccine, as well as low-osmolarity oral rehydration solution (ORS) and zinc, among health workers.

In 2006, clinical trial data showed that rotavirus vaccines were safe and effective in Latin American populations. That same year, RotaTeq was licensed in the United States. With a solution at hand to block the threat of severe diarrhea, the Nicaraguan Ministry of Health accepted Merck’s donation of enough of its new vaccine to immunize all babies born in Nicaragua for the next three years.

Next Introducing the vaccine

Photos, from top: Miguel Alvarez, PATH.