Rotavirus vaccines: viral shedding and risk of transmission.

Rotavirus causes gastroenteritis in almost all children by 5 years of age. Immunity to rotavirus is incomplete, with potential for recurrent infections occurring throughout life. Live rotavirus vaccines have been developed for the protection of children from severe wildtype rotavirus infections. Transmission of vaccine virus strains from vaccinated children to unvaccinated contacts harbours the potential for herd immunity, but also the risk of vaccine-derived disease in immunocompromised contacts. A review of rotavirus vaccine prelicensure studies shows that viral shedding and transmission were higher with the old tetravalent rhesus rotavirus vaccine than with the current human attenuated monovalent rotavirus vaccine and the pentavalent bovine-human reassortant vaccine. Immunocompromised contacts should be advised to avoid contact with stool from the immunised child if possible, particularly after the first vaccine dose for at least 14 days. Since the risk of vaccine transmission and subsequent vaccine-derived disease with the current vaccines is much less than the risk of wildtype rotavirus disease in immunocompromised contacts, vaccination should be encouraged.