Sinovac Biotech has published results from the Phase I/II clinical trials of its inactivated Covid-19 vaccine, CoronaVac, which triggered robust immune responses among healthy children and adolescents aged from three to 17 years in China.
The double-blind, randomised, placebo-controlled trials analysed the safety, tolerability and immunogenicity of the vaccine in 552 participants.
Study data showed that two intramuscular doses of CoronaVac administered 28 days apart were safe and well-tolerated in this paediatric population.
The majority of adverse reactions were mild to moderately severe and observed under seven days following each dose.
The Phase I immunogenicity data showed a positive seroconversion rate of neutralising antibody in all subjects after 28 days of complete vaccination with a low-dose or medium-dose vaccine.
In Phase II, seroconversion was noted in 96.8% of the subjects in the low-dose arm and all participants in the medium-dose arm 28 days after full vaccination.
Furthermore, the study demonstrated that paediatric subjects aged three to 17 years had robust immune responses as against adults aged between 18 and 59 years and those above 60 years after full vaccinations with medium doses.
A trend of lower vaccine responses with an increase in age was observed in the study.
Last month, CoronaVac obtained approval in China for emergency use among individuals aged between three to 17 years.
Sinovac Life Sciences China general manager Gao Qiang said: “We are encouraged by our findings that show CoronaVac is well tolerated and can induce strong immune responses.
“These results provide new information and suggest that further studies in other regions, involving larger, multi-ethnic populations, may provide additional data to help develop immunisation strategies that involve children and adolescents.”
In March 2021, Sinovac reported preliminary results from Phase I and II clinical trials of the vaccine in children and adolescents.
In a separate development, Novavax has published results from the final analysis of a Phase III clinical trial of its Covid-19 vaccine candidate in the UK.
Data showed that the vaccine had an 89.7% overall efficacy, with more than 60% of the cases caused due to the B.1.1.7 (Alpha) variant of the SARS-CoV-2 virus.
It also demonstrated a 96.4% efficacy against non-B.1.1.7 variants that are similar to the original virus.