US biotech firm Novavax said it had started clinical trials of its proposed Covid-19 vaccine on children, in a programme that will involve up to 3,000 adolescents aged 12-17.

Novavax said the trials would test “the efficacy (and) safety” of the vaccine, with participants receiving either the vaccine candidate or placebo in two doses, 21 days apart, according to an AFP report.

Participants will be monitored for up to two years after their injections.

The Novavax vaccine has not yet been authorised in any country, including for adults, but the company plans to file for emergency authorisation in Britain “in the second quarter of 2021”, followed by in the United States.