The World Health Organisation is calling on all nations to stop administering booster COVID-19 vaccines, except to immunocompromised people.
The WHO wants poorer countries to be prioritised for the foreseeable future.
Director-general Tedros Ghebreyesus said low-income nations still aren't getting sufficient supplies of vaccines.
He said: “No more boosters should be administered, except to immunocompromised people.
“Most countries with high vaccine coverage continue to ignore our call for a global moratorium on boosters, at the expense of health workers and vulnerable groups in low-income countries who are still waiting for the first dose.”
A growing number of wealthy countries are now administering booster vaccines.
Ireland is giving an additional dose to immunocompromised people, but has now extended the booster programme to healthcare workers and everyone over 60.
There's also now a growing number of scientists and experts saying widespread booster shots will be inevitable, although some have suggested countries may be better off waiting until vaccines targeting COVID variants are available.
The call for a boost moratorium comes amid rising COVID-19 case numbers in many countries in Europe, including Ireland.
WHO's Dr Michael Ryan said this all comes against the backdrop of reduced restrictions.
He observed: “We have come out of a summer period with increased mixing, increased mobility, increased gathering.
"The onus has been put on individuals to continue individual risk management… with little support from governments to be able to continue doing that.”
Dr Ryan noted that people are now “moving back inside” as the weather worsens, leading to increased possibility of virus transmission.
He said the high case numbers aren’t translating into the same number of hospitalisations as before in countries with high vaccination levels.
However, he warned there are countries - including in Europe - with low vaccine coverage, and those countries are now heading into a “very difficult winter”.