Treasury Secretary Janet Yellen said Monday that the lack of coronavirus vaccinations around the world, particularly in underdeveloped countries, poses a threat to the economies of all nations, including the United States, the Washington Post reports.

While so-called First World countries are preparing to reopen their economies and societies within the next year thanks to widespread availability and doses of vaccines, many less-developed nations are dealing not just with a lack of a system to obtain and administer vaccines, but with ongoing economic fallout from the ongoing pandemic, Yellen told the Chicago Council on Global Affairs.

“This would be a profound economic tragedy for those countries, one we should care about. But, that’s obvious. What’s less obvious — but equally true — is that this divergence would also be a problem for America,” Yellen said. “Our first task must clearly be stopping the virus by ensuring that vaccinations, testing and therapeutics are available as widely as possible.”

Yellen noted that countries with less economic power than the United States could not take on the robust recovery program promoted by President Joe Biden.  That lack of economic support, combined with recurring waves of coronavirus infections, could destabilize world markets and adversely affect the United States economy, regardless of domestic recovery programs.

Yellen called on wealthier countries to step up to provide assistance to needier nations, including by loosening intellectual property rights on vaccine formulae so they can be manufactured and distributed on a massive scale worldwide.

To help foreign nations, Yellen earlier this month said she would authorize the US to recognize “Special Drawing Rights,” a feature for countries in the International Monetary Fund that allows specific nations to exchange IMF credits for foreign currency.  Participating countries could exchange these credits for US dollars, allowing them to support their national economies.

Republican Senators such as Pennsylvania’s Pat Toomey and Louisiana’s John Kennedy objected to the use of SDRs, saying that they could be used by nations like China and Iran to skirt sanctions, to which Yellen noted the US is not obligated to honor any specific SDR claims and may unilaterally choose to ignore such requests.