Fall 2002 Issue
Battling a Global Killer of Children
Imagine ridding the world of a killer that takes the lives of 500,000 to 600,000 children in developing countries every year. This disease affects every child in the world – regardless of race or socioeconomic status.
The deadly enemy is rotavirus, and it is the most common cause of severe diarrhea among children worldwide. Five percent of children die from rotavirus diarrhea in developing countries each year. Globally, rotavirus is the culprit of 25 to 50 percent of hospitalizations for childhood diarrhea.
All babies are infected with rotavirus during their first few years of life, including children in the United States, and infections typically lead to mild diarrhea. However, one in eight children have such severe symptoms that they need medical attention for dehydration. And in developing countries where medical attention can be a two-day walk away, severe dehydration can lead to death.
What can be done to help? Many experts, including those at CDC, believe that a rotavirus vaccine could make a dramatic impact on improving public health in many countries.
“We know that rotavirus infection occurs among children in both developed and developing countries, so improvements in sanitation and hygiene are unlikely to have any impact on the incidence of the disease. In all settings, despite global programs for oral rehydration, rotavirus remains the most common cause of hospitalization for severe diarrhea,” says Roger Glass, M.D., Ph.D., chief of the Viral Gastroenteritis Section of CDC’s National Center for Infectious Diseases. “A rotavirus vaccine is targeted to reduce this toll of illness, hospitalizations and deaths.”
Learning from experience
In 1998, the U.S. Food and Drug Administration approved a rotavirus vaccine for children. It was withdrawn from the market because of an association between the vaccine and intussusception (bowel obstruction) among some babies during the first several weeks following vaccination.
“What we learned in providing the vaccine to nearly 1 million kids is that it was effective and that the approach was scientifically sound,” says Glass, who notes that new vaccines are not expected to be associated with intussusception. Current studies will help further understanding about the link between intussusception and rotavirus, before and after the vaccine is introduced.
“Everyone in the international community would like to see a rotavirus vaccine developed, which is exciting,” he says. “After years of waving the flag for rotavirus, now we clearly have the world’s attention about a problem that’s a major killer of children.”
CDC and its collaborators aim to make a rotavirus vaccine a reality. With help from the CDC Foundation and funding from contributors including the Children’s Vaccine Program at PATH (Program for Appropriate Technology in Health), several new exciting rotavirus projects are underway in Asia and India that have the potential to save hundreds of thousands of children’s lives each year.
Asian rotavirus project focuses on surveillance
Understanding the impact of a disease is the first step in introducing a successful vaccine. To that end, CDC is coordinating a three-year study in nine Asian countries to develop hospital-based surveillance systems for rotavirus. These studies will use standardized methods to help determine the prevalence of rotavirus in Asia. That way, if and when a vaccine is introduced, there will be a baseline for comparison.
“We’re introducing a test for children who are hospitalized for acute diarrhea, to diagnose whether or not they have rotavirus,” Glass explains. “By setting up this surveillance activity, pediatricians will have access to this diagnostic test for the first time. We hope that they’ll be able to learn for themselves how important and common this disease really is. They can also begin thinking about how a rotavirus vaccine might decrease the number of hospitalizations they face.”
He adds, “Through the studies, we can also learn about differences in the epidemiology throughout the region, and find out about different strains of rotavirus that need to be attacked by a vaccine.”
Julie Jacobson, M.D., program officer, Children’s Vaccine Program, PATH, a funder of the program, notes that the Asian rotavirus project will provide the framework for the eventual control of severe rotavirus disease in the developing world.
“This work – accompanied by our work to produce a developing country vaccine candidate – could completely change the context for rotavirus control,” says Jacobson. “First, this data will allow countries to have an understanding of the impact of rotavirus in their own country and to make informed public health decisions for their people. Secondly, an affordable vaccine that is made in the developing world will support the economic and technical growth of a developing nation.”
Developing a rotavirus vaccine in India
In India, where the international health community’s ultimate goal is to develop a rotavirus vaccine, CDC is involved in a five-year rotavirus project. Through the project, CDC is providing lab training, monitoring vaccine development, testing rotavirus clinical studies specimens and providing technical assistance for epidemiological and surveillance studies before and after a rotavirus vaccine is introduced.
“We’ve done a lot of background research in India. Now, we’ve identified two strains as vaccine candidates,” says Glass. “Our goal is to have Bharat Biotech prepare a rotavirus vaccine from these strains, and test them in New Delhi. In five years, our hope is to have an Indian rotavirus vaccine that’s been tested in Indian children.”
He explains that studies in India began with a simple observation: for some unknown reason, newborn babies who were infected with rotavirus in the hospital nursery had no symptoms. These children were protected against subsequent severe rotavirus incidents. “It was really like a natural vaccine,” Glass says, “and we realized that the nursery strain could be a potential vaccine candidate for India.”
-Lisa Splitlog
The Asia rotavirus project is supported by grants from PATH/CVP, and GlaxoSmithKline Biologicals through the CDC Foundation. Merck and the World Health Organization provide additional support to the surveillance sites in Asia.
The India rotavirus project is supported by a grant from PATH/CVP through the CDC Foundation. The Indo-U.S. Vaccine Action Program/World Health Organization provide support directly to the program. India rotavirus project collaborators include the National Institutes of Health, Bharat Biotech International Limited, Stanford University, All India Institute of Medical Sciences, and the Indian Institute of Science.