Rotavirus vaccine,live(Wuhan Institute of Biological Products)

The primary objective is to evaluate the protective efficacy of three doses of hexavalent reassortant live rotavirus vaccine against severe acute gastroenteritis caused by natural infection with rotavirus 14 days after vaccination. The secondary objective is to evaluate the protective efficacy against natural infection with any type of rotavirus, types contained in the vaccine strain and acute gastroenteritis caused by all causes 14 days after vaccination, the protective efficacy against severe acute gastroenteritis caused by types contained in the vaccine strain, and the safety and immunogenicity of vaccination.