Rotaviruses are the most common cause of severe gastroenteritis in infants and young children. In the United States, rotaviruses cause an estimated 50,000 pediatric hospital admissions and 20 deaths each year. In less developed countries, rotavirus is responsible for 600,000-800,000 deaths among infants and young children each year.
In 1998, a live attenuated rotavirus vaccine, Rotashield, was licensed in the United States to prevent gastroenteritis-related severe diarrhea in infants. However, it currently is unavailable due to safety concerns raised by the Centers for Disease Control and Prevention (CDC). The CDC reported that the vaccine increased the risk of intussusception by approximately 20-fold immediately following the first dose of vaccine compared with nonvaccinated infants.
A recent study conducted by researchers at the National Institute of Allergy and Infectious Diseases and the Agency for Healthcare Research and Quality was unable to detect an increase in hospital infant admission rates for intussusception in a period following introduction of the vaccine (October 1998 to June 1999) compared with a similar prevaccine period (October 1997 to June 1998). AHRQ researcher Anne E. Elixhauser, Ph.D., and her colleagues analyzed hospital discharge data from the Agency's Healthcare Cost and Utilization Project (HCUP) for 1993-1999 from 10 States, where an estimated 28 percent of infants had received Rotashield. They compared hospitalization rates for intussusception during pre- and postvaccination periods for infants younger than 12 months.
Overall infant hospitalizations for intussusception during the Rotashield period compared with the previous period was 4 percent lower (10 cases) by direct comparison and 10 percent lower (27 cases), after adjustment for trends, suggesting a negligible risk for the vaccine. Among infants aged 45-210 days (target age range for a first Rotashield dose), they estimated an increase in intussusception admissions of 1 percent (one excess admission) by direct comparison and 4 percent (4-6 excess admissions) by trend comparison, corresponding with a risk range of one excess admission in 66,000 to 302,000 infants. This contrasted with an expected increase of 23-100 percent based on CDC relative risk estimates. The authors suggest that this finding of a lower than expected risk of intussusception due to rotavirus vaccine should be considered in decisions to make the vaccine available, especially among populations at high risk for rotavirus infection. An extended study including 21 HCUP States will be completed in 2002.
More details are in "Effect of rotavirus vaccination programme on trends in admission of infants to hospital for intussusception," by L. Simonsen, Ph.D., D.M. Morens, M.D., Dr. Elixhauser, and others, in the October 13, 2001, Lancet 358, pp. 1224-1229.
Reprints (AHRQ Publication No. 02-R016) are available from the AHRQ Publications Clearinghouse.
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