Striking an increasingly exasperated tone, the WHO said the world would look back on itself with shame if it knowingly chose to leave the world's weakest at the mercy of the pandemic.
Vaccines are still seen as the best way to allow economies to reopen while keeping the public safe, but many poorer nations are still lagging far behind their richer counterparts -- tens of millions in Asian cities are now once again living in lockdown.
"The agreements, which come at a time when the Delta variant is posing a rising risk to health systems, will begin to make 110 million doses immediately available to participants of the COVAX Facility, with options for additional doses," GAVI said.
The initiative also seeks to address concerns that Moscow and Beijing have been taking advantage of the worldwide crisis to spread influence through distribution of their own inoculations in a so-called "vaccine diplomacy" contest.
Vietnam has placed orders for more vaccines from several suppliers and received around 2.9 million doses from its purchases and via the international COVAX scheme.
Vietnam has registered 6,396 coronavirus cases so far, half of which were recorded in the latest outbreak.