GENEVA — The head of the World Health Organization is pleading with rich countries to check before ordering additional COVID-19 vaccine for themselves whether that undermines efforts to get vaccine to poorer nations.

Wealthy nations have snapped up several billion doses of vaccine, while some countries in the developing world have little or none. European nations have given financial support to the U.N.-backed COVAX effort to vaccine the world’s most vulnerable people, and are considering sharing some of their own doses.

WHO Director-General Tedros Adhanom Ghebreyesus said Monday that “even if you have the money, if you cannot use the money to buy vaccines … having the money doesn’t mean anything.”

Speaking after talks with Germany’s president, he said some rich countries’ approaches to manufacturers for more vaccines are “affecting the deals with COVAX, and even the amount that was allocated for COVAX was reduced because of this.” He didn’t name those countries.

Tedros added that rich countries need to “cooperate in respecting the deals that COVAX did” and make sure before they seek more vaccines that their requests don’t undermine those deals. But, he said, “I don’t think they’re asking that question.”