"(Acting) strategically and globally is actually in each country's national interest - no one is safe until everyone is safe," he told a virtual briefing calling for an end to "vaccine nationalism."
He said he had sent a letter to all WHO members asking them to join the multilateral COVAX vaccine effort.
More than 21.9 million people have been reported to be infected by the novel coronavirus globally and 772,647 have died, according to a Reuters tally.