WHO Director-General Tedros Adhanom Ghebreyesus said on Friday that "vaccine nationalism" would only slow the effort to quash the pandemic and called for vaccines to be used fairly and effectively.
"Vaccine nationalism will prolong the pandemic, not shorten it," Tedros said.
Tedros said 78 high-income countries had now joined the "COVAX" global vaccine allocation plan, bringing the total to 170 countries, and the "number is growing".
He urged others to join by the Sept.
18 deadline for binding commitments.
"If and when we have an effective vaccine, we must also use it effectively ... In other words, the first priority must be to vaccinate some people in all countries, rather than all people in some countries," he said.