Cases of rotavirus worldwide are higher than previously thought, according to studies by Dr. Umesh Parashar of the Centers for Disease Control and Prevention (CDC) presented at a global symposium on rotavirus here today.

There are now over 608,000 deaths annually from rotavirus, Parashar said. His previous estimates showed around 440,000 deaths. Total deaths from all diarrheas are 1.56 million worldwide, with 39 percent of those now attributable to rotavirus, instead of the previous estimate of 22 percent, he said.

"Rotavirus infections are ubiquitous and nearly 95 percent of children worldwide are infected by 5 years of age," he said, noting that "improvements in hygiene and sanitation are unlikely to have a significant impact on (rotavirus) disease prevention."

"Compared with children in industrialized countries, those in developing countries are infected at a younger age, have year-round disease with less distinct seasonality, are more often infected with unusual or multiple strains of rotavirus, and are more likely to suffer from severe outcomes of disease," Parashar said.

The rotavirus symposium was convened by the Pan American Health Organization, (PAHO/WHO), the Albert B. Sabin Vaccine Institute, the CDC, and the U.S. National Institutes of Health.

Dr. Jon K. Andrus, PAHO's head of immunization efforts, said the aim of the Organization’s vaccine programs is to reduce inequities and make all vaccines, including new ones, affordable for poor families. The PAHO revolving fund, he said, is used to buy vaccines in bulk to reduce costs and make them more widely available and could be used for new rotavirus vaccines.

In Mexico, 2,000 children die of diarrhea each year, according to Dr. Romeo Rodriguez of the National Immunization Council of Mexico, and a vaccine could cut those deaths by 40 percent. Each episode of diarrhea costs families an average of US$103, which represents 86 percent of the monthly income for families living on minimum wage.

Though no vaccine against rotavirus is currently on the market, several are being developed and rotavirus is a high priority for developing countries where 85 percent of the deaths occur, most from severe dehydration. Rodriquez said Mexico was likely to be the first country to introduce a vaccine against Rotavirus now under development, perhaps by next April.

Dr. Ciro de Quadros of the Sabin Vaccine Institute said costs of a rotavirus vaccine are not yet known, but its effects would be that physicians and services would see many fewer diarrhea cases and deaths.

Experts including Dr. Ruth Bishop, discoverer of rotavirus, Dr. Albert Kapikian, inventor of the rotavirus vaccine, and many others are in Mexico to discuss all aspects of rotavirus. Experts from leading public health and donor organizations, including PAHO, WHO, the Global Alliance for Vaccines and Immunization, and the Rotavirus Vaccine Program are all making presentations.