WEDNESDAY, June 25 (HealthDay News) -- A recent vaccine for rotavirus -- a leading cause of vomiting and diarrhea in infants and children -- may account for this year's less severe season, the U.S. Centers for Disease Control and Prevention said Wednesday.

The highly contagious virus is shed in the stools of infected people and is transmitted by contaminated hands and objects. Children can transmit the virus before and after they become sick with diarrhea.

The nation's leading cause of severe gastroenteritis in infants and young children, rotavirus typically is responsible for some 410,000 doctor visits, up to 270,000 trips to the emergency room, up to 70,000 hospitalizations, and as many as 60 deaths in the United States each year.

The numbers at many "surveillance centers" nationwide have been down sharply in the ongoing season. Lab tests for the virus are down 37 percent from average, and positive tests are 79 percent lower than usual, the CDC said in a prepared statement.

Also, rotavirus activity was delayed about three months from its typical start in November, and it peaked in April this year instead of the usual peak time of March, the agency said.

In 2006, Merck & Co.'s RotaTeq was introduced in the United States for routine vaccination of children at ages 2 months, 4 months, and 6 months.

"The changes appear to be greater than expected based on the protective effects of the vaccine alone," said Dr. Anne Schuchat, director of the National Center for Immunization and Respiratory Diseases at the CDC. "It is also possible the current levels of vaccination may be helping to decrease the spread of rotavirus to unvaccinated individuals in the community."

Also Wednesday, federal advisers endorsed the use of a second vaccine to combat rotavirus. The new two-dose vaccine for infants was approved by the U.S. Food and Drug Administration in April and is made by GlaxoSmithKline, the Associated Press reported.

More information

The CDC has more about rotavirus.