The head of the World Health Organisation is calling on rich countries with large supplies of coronavirus vaccines to refrain from offering booster shots through the end of the year, expanding an earlier request that has largely fallen on deaf ears.

WHO Director-General Tedros Adhanom Ghebreyesus also said that he was “appalled” at comments by a leading association of pharmaceutical manufacturers a day earlier who said vaccine supplies are high enough to allow for both booster shots and vaccinations in countries in dire need of jabs but facing shortages.

“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 in Geneva, according to an AP report.