With the World Health Organisation (WHO) having issued interim recommendations for the use of the Sinovac-CoronaVac vaccine against Covid-19, now further results from a multi-centre, case-driven, randomised, double-blind, placebo-controlled Phase III clinical trial show that CoronaVac is safe in healthy children and adolescents aged 3 to 17 years old. The study is being conducted by Sinovac Biotech in Chile, Malaysia, the Philippines and South Africa and involves 2,140 participants aged 3 to 17 years, including 684 participants in a safety subgroup. Further studies will extend the age group to 6 months.
Data from the safety subgroup revealed that the incidence of adverse reactions after the second dose was much lower than after the first dose. Common side effects include pain at the injection site, headache, and fever. Most adverse events were mild/moderate (Grade 1 and 2) with no severe adverse reactions.
CoronaVac was found to be safe in children and adolescents between the ages of 3 to 17 years old. The primary results from the global, multi-centre Phase III clinical trial show that the overall incidence of adverse reactions is similar to Phase I/II clinical trials conducted on adolescents and children in Mainland China. Further results of this study will provide clinical evidence for countries to approve the use of CoronaVac in children and adolescents between 6 months to 17 years of age.
Since September 2021, countries that have approved the use of CoronaVac in children and adolescents include Chile, Ecuador, El Salvador, Colombia, Cambodia, and Indonesia. By the end of October, China had administered more than 110 million doses of CoronaVac to children under the age of 18.
Results of the Phase I/II clinical trial which assessed the safety of CoronaVac in children and adolescents between the ages of 3 to 17 were published in The Lancet-Infectious Diseases on 28 June. The results showed that CoronaVac is well tolerated and safe for use in children and adolescents between the ages of 3 to 17 and that the inactivated vaccine could also induce a stronger immune response.
As part of the same trial, a Phase II study on immune persistency was conducted in 180 volunteers aged from 3 to 17 years. The results showed that, three months after two doses of the vaccine, seroconversion rates were 100%. The geometric mean titre (GMT) of neutralising antibody was close to the level recorded at 28 days after vaccination and remained significantly higher than the level recorded in adults and elderly at 28 days after vaccination. This indicates that CoronaVac has stable and good immunogenicity among the children and adolescent population, recording better results compared to those in people aged 18 and above.