The World Health Organisation's (WHO) vaccine advisory panel recommends that people who are immunocompromised or received an inactivated vaccine should receive a booster dose of a Covid-19 shot, the head of the panel said on Thursday.
The recommendation comes after the Strategic Advisory Group of Experts (SAGE) on immunisation held a meeting on Tuesday to evaluate the need for Covid-19 boosters.
Speaking in a briefing, SAGE chair Alejandro Cravioto said emerging data showed that vaccines' efficacy against Covid-19 wanes, with a significant decline seen in older people in particular.
Inactivated vaccines which take the SARS-CoV-2 virus and inactivate or kill it using chemicals, heat or radiation, are made by Chinese manufacturers Sinovac Biotech, state-owned Sinopharm and India's Bharat Biotech.
A single dose of the Johnson & Johnson vaccine is still effective, but data from the company's clinical trials using two doses clearly show the benefit of having further vaccination, Cravioto said.