The World Health Organisation (WHO) has recommended that people who are immunocompromised or received an inactivated Covid-19 vaccine should receive a booster dose to protect against waning immunity.

Many countries have been rolling out booster shots, targeting the elderly and people with underlying health issues, but worries about the new, more transmissible Omicron variant have prompted some to expand their use to larger portions of their populations, Reuters reports.

With vaccination rates worryingly low in much of the developing world, the WHO has said in recent months that administering primary doses — rather than boosters — should be a priority.

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 and was largely in line with guidance given in October.