A higher dose of the Chinese vaccine CoronaVac was “well tolerated and safe, and induced neutralising antibody responses in children and adolescents aged 3-17 years”, a study in the recent edition of the peer-reviewed journal Lancet Infectious Diseases has stated.
The seroconversion rates of neutralising antibodies in children and adolescents with two different doses were over 96% after a double-dose vaccination, the paper reported.
The double-blind randomised, controlled, phase 1/2 clinical trial of CoronaVac (inactivated SARS-CoV-2), in healthy children and adolescents aged 3-17 years was conducted at the Hebei Provincial Center for Disease Control and Prevention in Zanhuang (Hebei, China).
On the basis of the results of previous trials and considering the relative low weight of this population, two different doses — 1·5μg (micrograms) and 3·0μg — were adopted in this study. Two doses were delivered via injection, 28 days apart.
The paper by Bihua Han et al, notes that primary safety endpoint was adverse reactions within 28 days after each injection in all participants who received at least one dose. Researchers also noted the seroconversion rate (development of antibodies specific to SARS-CoV-2) 28 days after the second injection.
The paper claimed: “Most adverse reactions were mild and moderate in severity. Injection site pain was the most frequently reported event (73 [13%] of 550 participants), occurring in 36 (16%) of 219 participants in the 1·5μg group, 35 (16%) of 217 in the 3·0μg group, and two (2%) in the placebo group. Most of these reactions occurred within 7 days after vaccination and participants recovered within 48 hours
In phase 2, seroconversion was seen in 180 of 186 participants in the 1·5μg group and 180 of 180 participants in the 3·0μg group. The neutralising antibody titres induced by the 3·0μg dose were higher than those of the 1·5μg dose. The results support the use of 3·0μg dose with a two-dose schedule for further studies in children and adolescents, the authors argued.
The patients will be followed up for a year to study long-term immunogenicity and safety.
