GENEVA — The head of the World Health Organization is calling on rich countries with large supplies of coronavirus vaccines to refrain from offering booster shots through the end of the year.

WHO Director-General Tedros Adhanom Ghebreyesus says he was “appalled” at comments by pharmaceutical manufacturers who say vaccine supplies are high enough to allow for both booster shots and vaccinations in countries in dire need of shots but facing shortages.

The WHO chief says, “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.”

Tedros had previously called for a “moratorium” on booster shots through the end of September, but the United States and other countries have begun or are considering plans to offer them to their vulnerable people.