Post-licensure experience with rotavirus vaccination in high and middle income countries; 2006 to 2011

Rotavirus causes one-third to one-half of severe diarrheal disease in children under the age of five years worldwide. In 2006 two rotavirus vaccines became available and, in the intervening years, approximately thirty countries have introduced them into their immunization programs, primarily in high-income and middle-income settings. Major reductions in rotavirus hospitalizations have been observed in a number of these locations, and in select countries, there have been impacts on gastroenteritis mortality associated with rotavirus vaccine introduction. In addition to these direct health benefits, reduced gastroenteritis risk has been documented in unvaccinated groups, including older children and adults, suggesting indirect benefits (i.e. herd immunity). In this paper, we summarize what has been learned from programs studying post-licensure vaccine effectiveness, impact on health-care utilization and death, safety issues (namely, intussception and the detection of adventitious viruses) and the potential selective pressure of vaccination on the diversity of rotavirus genotypes.