China’s CoronaVac jab safe and effective in children as young as three, study says

China’s CoronaVac vaccine is safe and effective to use in children as young as three, new research has shown.

In a study of 550 young people, two doses of the vaccine were found to generate a strong antibody response among children and adolescents aged 3-17 years.

More than 96 per cent of children who received two doses of the vaccine – manufactured by Sinovac – developed antibodies against Sars-CoV-2, the virus that causes Covid-19.

Most adverse reactions were mild or moderate, with pain at the injection site the most commonly reported symptom, the researchers said.

The findings, published in The Lancet, further underpin the safety profile of the Covid jabs, and follow recent calls from scientists to widely vaccinate children and adolescents.

A number of leading experts told The Independent that the move to inoculate 12 to 17-year-olds would help to better control and reduce transmission rates, protect adolescents from severe infection and long Covid, and could also lessen the need to roll out booster jabs.

The CoronaVac vaccine has already been approved for emergency use in China among 3-year-olds. Israel, France and the US have meanwhile started using the Pfizer vaccine for children aged over 12, but, in the UK, health officials are awaiting further data on the safety profile of the jab and rates of post-Covid syndromes in adolescents.

Children and adolescents with Covid-19 usually have mild or asymptomatic infections compared with adults; however, a small number may still be at risk of severe illness,” said Qiang Gao, of Sinovac Life Sciences.

“They can also transmit the virus to others, making it vital to test the safety and effectiveness of Covid-19 vaccines in younger age groups.

“Our finding that CoronaVac was well tolerated and induced strong immune responses is very encouraging, and suggests that further studies in other regions, involving larger, multi-ethnic populations, could provide valuable data to inform immunisation strategies involving children and adolescents.”

The 550 trial participants were recruited into the study between 31 October and 30 December 2020. Children were given varying vaccine doses of different strength to test immune response and side effects.

Based on their results, the authors recommend two 3 microgram doses of the vaccine for children and adolescents aged 3-17 years.

The authors acknowledge some limitations to their study. T-cell responses – which are responsible for seeking out and killing infected cells – were not assessed.

Professor Bin Cao, of the China-Japan Friendship Hospital, said children must be vaccinated in all populations to ensure that herd immunity can be reached against the new and emerging Covid variants.

“Herd immunity against Covid-19 is the prerequisite to end this pandemic, either through vaccinations or natural infection. Most estimates placed the threshold at 65-70 per cent of the population gaining immunity, mainly by vaccination,” he said. “However, widely circulating virus variants and persistent hesitancy on vaccine make this threshold difficult to reach.

“Thus, the calculation has to be revised upward and children must be covered in the immunisation campaign.”