GENEVA, Switzerland (AP) — Rich countries with large supplies of COVID-19 vaccines should refrain from offering booster shots through the end of the year and make the doses available for poorer countries, the head of the World Health Organization (WHO) said yesterday, doubling down on an earlier appeal for a “moratorium” on boosters that has largely been ignored.

WHO Director General Tedros Adhanom Ghebreyesus also said he was “appalled” after hearing comments Tuesday from a top association of pharmaceutical manufacturers that vaccine supplies are high enough to allow for both booster shots for people in well-supplied countries and first jabs in poorer countries that face shortages. He said that’s already been the case.

“I will not stay silent when companies and countries that control the global supply of vaccines think the world’s poor should be satisfied with leftovers,” he told a news conference.

“Because manufacturers have prioritised or been legally obliged to fulfil bilateral deals with rich countries willing to pay top dollar, low-income countries have been deprived of the tools to protect their people.”

Tedros had previously called for a moratorium on boosters through the end of September. But wealthy countries — including Britain, Denmark, France, Greece, Germany, and Spain — have begun, or are considering, plans to offer third shots of two-dose vaccines to their vulnerable people such as the elderly or those with compromised immune systems.

Israel has been providing third doses to a wide swath of people who already received a full two-dose regimen months earlier. And last month, United States health officials recommended that all Americans get boosters to shore up their protection amid evidence that the vaccines’ effectiveness is falling.

But WHO officials insist the scientific justification for boosters remains unclear.

Tedros acknowledged that third doses might be necessary for at-risk groups, but said: “We do not want to see widespread use of boosters for healthy people who are fully vaccinated”.

US health officials are continuing to assess the science and utility of boosters, and there are growing indications that the US may miss the Biden administration’s September 20 target date for a wide roll out of extra shots for vaccinated people.

The WHO chief said he received a message of “clear support” from health ministers at a meeting of the influential Group of 20 countries this week for a commitment to help hit a WHO target that all countries vaccinate at least 40 per cent of their people by year’s end.

“A month ago, I called for a global moratorium on booster doses, at least until the end of September to prioritise vaccinating the most at risk people around the world who are yet to receive their first dose,” Tedros said.