Though Biden has sought to reverse many of Trump’s policies, the U.S.’s commitment to prioritizing its own vaccine procurement remains unchanged. From a global-distribution standpoint, the U.S. joining COVAX doesn’t change the fact that most wealthy countries have already reserved the lion’s share of the world’s available vaccine supply. “We’re sort of past trying to say, ‘Okay rich countries, stop buying doses,’” Andrea Taylor, the assistant director of programs at Duke’s Global Health Innovation Center, told me. As far as equitable access is concerned, “that ship has sailed.”

This doesn’t mean that nothing can be done to rectify the situation. Wealthy countries could simply contribute more funding to COVAX, which would give the initiative the buying power it needs to reserve a fair share of doses for the countries relying on it. The initiative announced this week that it will aim to distribute more than 300 million doses—enough to cover approximately 3 percent of receiving countries’ populations—by the end of June. Though COVAX has raised more than $6 billion so far, a Gavi spokesperson told me that it will need a further $2 billion to hit its 2021 targets. Still, as Taylor noted, most of the priority manufacturing capacity for this year has already been reserved, meaning that even if COVAX were to secure more doses, companies wouldn’t necessarily have the means to produce them all immediately. Indeed, current models project that it will take years before there are enough doses to meet global demand.

The other, perhaps more realistic option is for high-income countries to donate doses directly to low-income ones. Under this solution, which has already been championed by Norway, donations would occur in tandem with richer countries’ domestic vaccination programs, ensuring that poorer states aren’t put in the position of having to wait until the world’s wealthiest populations are vaccinated before they can receive lifesaving supplies.