The purpose of the study was to assess the safety, immunogenicity, and lot-to-lot consistency of live attenuated varicella vaccination in a Chinese population aged 1–3 years. The randomized, double-blind phase III study was carried out in Henan Province, China. This study comprised 1197 participants in total. Subjects were randomly allocated to one of three batches of commercial-scale (CS) vaccination or the licensed pilot scale (LPS) vaccine in a 2:2:2:1 ratio. The rate of seroconversion and neutralizing antibody titers (NATb) were measured on day 0 before immunization and on day 30 after vaccination. For 30 days after immunization, safety data were collected. The geometric mean titers (GMTs) of the three CS groups after immunization were 25.04, 24.47, and 25.88, respectively. In susceptible patients, the GMTs corrected for confounders ratio of each pair of lots ranged from 0.67 to 1.50. The seroconversion rate difference between the pooled CS group and the LPS group was 3.82. 

Meanwhile, there was no difference in the percentage of requested local, systemic, and unsolicited adverse responses among the four groups, and the majority of the adverse reactions were mild or moderate in severity. In terms of safety and immunogenicity, the CS group was comparable to the LPS group. Three successive CS lots have consistent consistency.