The United States continues to see dividends from efforts to vaccinate young children against rotavirus infection, with fewer children hospitalized for diarrheal illness through 2011, according to an analysis published in the journal Pediatrics today.
In 2006, the US Centers for Disease Control and Prevention’s Advisory Committee on Immunization Practices first recommended vaccination of US infants with a pentavalent rotavirus vaccine, effective against 5 variants of rotavirus. Before that time, severe gastrointestinal illnesses caused by rotavirus infections sent between 55 000 and 70 000 children to the hospital each year, resulting in up to 60 deaths. A second vaccine, a monovalent version, was added to the recommended vaccines list in 2008.
Previous studies documented decreased rates of diarrheal illness in the first 2 years after vaccination began. But limited data have been available on how the newer vaccine compares with the older one and whether the gains seen early on have been sustained over the long term. Eyal Leshem, MD, of the National Center for Immunization and Respiratory Diseases, and colleagues analyzed claims in the MarketScan Commercial Claims Encounters Database to compare rates of diarrheal illness in children younger than 5 years before vaccination was recommended and every year after, through 2011.
They found that by December 2010, rotavirus vaccination rates among children younger than 5 years reached 58% for the pentavalent vaccine and 5% for the monovalent version. Compared with the rate of hospitalization for rotavirus-related illness in the prevaccination era (2000-2006), they found a 75% reduction in the hospitalization rate in 2007-2008, a 60% reduction in 2008-2009, 94% in 2009-2010, and 80% in 2010-2011.
The rate of hospitalization for rotavirus among those vaccinated was reduced by 92% (for the pentavalent vaccine) and 96% (for the monovalent version) compared with hospitalization rates for rotavirus among unvaccinated children.
Even unvaccinated children experienced decreased rates of rotavirus hospitalization after vaccination began, with a 50% reduction in 2007-2008, a 77% reduction in 2009-2010, and a 25% reduction in 2010-2011. Presumably, higher vaccination rates reduced the amount of rotavirus circulating in the population, protecting even those who were unvaccinated.
The authors estimate that the rotavirus vaccination prevented 176 587 US children from being hospitalized for rotavirus between July 2007 and June 2011. Additionally, they estimated 242 335 fewer emergency department visits and about 1.1 million fewer outpatient visits for diarrheal illness during this period. About $924 million in health costs were saved as a result of these reductions, according to the authors’ calculations.