Clinical trials

This is a single armed, Phase 3 study to assess the immunogenicity and safety of the varicella vaccine manufactured by Sinovac. A total of 300 healthy participants aged 1-12 years will be enrolled. All participants will receive a single dose of varicella vaccine manufactured by Sinovac.

This study aim to assess the immunogenicity and safety of interchangeable administration of the second dose of varicella vaccine. A total of 300 healthy participants aged 15 months - 12 years will be enrolled. Written informed consent form will be obtained from participants' parents or legally acceptable representatives (and assents will be obtained from participants aged above 9 years old and written consent forms will be prepared and consent will be obtained in writing if possible from the participants aged 3-8 years old.) before enrollment. Participants will be assigned to 5 groups according to the brand of first dose varicella vaccine they received at the age of 12 months. All participants will receive the second dose of varicella vaccine manufactured by Sinovac. The duration of individual participation from enrollment to the last onsite visit will be a maximum of 42 days. The end of study is considered the completion of the last visit for the last participant in this study. Blood samples (2.5 - 3.0ml per time) for immunogenicity assessment will be collected. The blood samples will be collected before vaccination and 42 days after vaccination.

This is a phase Ⅳ clinical trial of live attenuated varicella vaccine manufactured by Sinovac (Dalian) Vaccine Technology Co., Ltd.The primary objective of this study is to evaluate the immunogenicity of live attenuated varicella vaccine co-administered with MMR vaccine or DTaP vaccine. The secondary objective is to evaluate the safety of the vaccines when administered simultaneously.

This study consists of two parts. Part 1 is a retrospective cohort study and part 2 is a prospective cohort study. In Part 1 ,the scaled logit model was used to assess the correlation between varicella-zoster virus (VZV) antibody titers using fluorescent-antibody-to-membrane-antigen assay (FAMA) 30 days after varicella vaccine immunization and the risk of subsequent varicella breakout/disease , to determine the protective threshold for achieving FAMA antibodies. Part 2 was to validate the model in part 1.