June 5 (Bloomberg) -- Vaccines against rotavirus, the main cause of severe diarrhea in preschoolers, were recommended for global use by the World Health Organization, which may boost sales for producers Merck & Co. and GlaxoSmithKline Plc.

Rotateq, made by Whitehouse Station, New Jersey-based Merck and Rotarix, sold by London-based Glaxo, should be included in all national immunization programs to provide protection against a virus that is responsible for more than 500,000 diarrheal deaths and 2 million hospitalizations annually among children, the Geneva-based WHO said in a statement today.

The virus spreads rapidly, most likely through person-to- person contact, airborne droplets or possibly contact with contaminated toys, according to WHO. Symptoms usually appear two to three days after infection, and include projectile vomiting and very watery diarrhea, often with fever and abdominal pain.

“This is a tremendous milestone in ensuring that vaccines against the most common cause of lethal diarrhea reach the children who need them most,” said Thomas Cherian, a vaccines specialist with the WHO.

Merck’s Rotateq, given in a three-shot series, was approved in the U.S. in 2006 and generated $664.5 million last year. Glaxo gained approval for its two-shot Rotarix vaccine in 2008. It had sales last year of 167 million pounds ($268 million).

No Treatment

There is no specific drug treatment for rotavirus infection. Immunity after infection is incomplete, though repeat infections tend to be less severe than the original bout.

About 527,000 young children die from rotavirus-induced diarrhea annually, 85 percent of them in lower-income countries of Africa and Asia, WHO says. Fourteen of those nations are eligible for funding to buy vaccines through the GAVI Alliance, a group supporting childhood immunization in poor countries.

The recommendation extends advice made in 2005 on vaccination in the Americas and Europe, where studies showed the shots were safe and effective. New data from trials gauging efficacy in countries where the disease kills more children led to the recommendation that the inoculation should be used globally, WHO said.

To contact the reporter on this story: Jason Gale in Singapore at j.gale@bloomberg.net.

Last Updated: June 5, 2009 04:32 EDT