File Photo: World Health Organization Director-General Tedros Adhanom Ghebreyesus speaks during a news briefing on COVID-19 via video link from the WHO headquarters in Geneva. AFP
The UN health agency has long warned that the glaring inequity in access to Covid vaccines, which has left many vulnerable people in poorer nations without a single jab as richer countries roll out broad booster programmes.
"Blanket booster programmes are likely to prolong the COVID-19 pandemic, rather than ending it, by diverting supply to countries that already have high levels of vaccination coverage, giving the virus more opportunity to spread and mutate," WHO Director-General Tedros Adhanom Ghebreyesus told reporters.
"No country can boost its way out of the pandemic."
His comments came as the Omicron variant's lightning dash around the globe since it was first detected in South Africa last month has dampened hopes the worst of the pandemic is over.
The new variant is spreading at unprecedented speed and has already been detected in 106 countries, the WHO said.
Early data indicating that the heavily-mutated variant is not only more transmissible than previous strains, but could be better at dodging some vaccine protections, although additional doses appear to push protection levels higher.
But Tedros said Wednesday that the existing vaccines continue to provide significant protection against severe disease from Omicron.
"It's important to remember that the vast majority of hospitalisations and deaths are in unvaccinated people, not un-boosted people," he said.
He also stressed that we all must take all necessary precautions to halt the spread of Covid as we head into the Christmas holiday.
"Boosters cannot be seen as a ticket to go ahead with planned celebrations," he said.
The WHO's Strategic Advisory Group of Experts (SAGE) on Immunisation said Wednesday that at least 126 countries around the world have already issued recommendations on boosters or additional vaccine doses, and 120 had started implementing those programmes.
"No low-income country has yet introduced a booster vaccination programme," it said in a statement.