The Biden administration is being criticized for falling short on its pledge to provide vaccines to the world.

President Biden, who has pledged to fight the coronavirus pandemic by making the United States the “arsenal of vaccines” for the world, is under increasing criticism from public health experts, global health advocates and even Democrats in Congress who say he is nowhere near fulfilling his promise.

Mr. Biden has either donated or pledged about 600 million vaccine doses to other countries — a small fraction of the 11 billion that experts say are needed to slow the spread of the virus worldwide. His administration has also taken steps to expand Covid-19 vaccine manufacturing in the United States and India, and is supporting production in South Africa and Senegal to expand access to locally produced vaccines in Africa.

But with the administration now recommending booster doses for vaccinated Americans starting next month, outraged public health experts and many Democrats on Capitol Hill are calling on the president to move more aggressively to scale up global manufacturing. In an analysis published on Thursday, the AIDS advocacy group PrEP4All found that the administration had spent less than 1 percent of the money that Congress appropriated for ramping up Covid-19 countermeasures on expanding vaccine manufacturing.

Congress put a total of $16.05 billion in the American Rescue Plan this year, in two separate tranches, that could be used to procure and manufacture treatments, vaccines and tools for ending the pandemic. But PrEP4All found that all told, the administration had spent $145 million — just $12 million of it from the American Rescue Plan — to expand vaccine manufacturing.

The United States has donated 115 million surplus doses, and has purchased 500 million more from Pfizer and BioNTech to be distributed through Covax, more than any other country. But that is still a minute fraction of the 12 billion doses Duke University’s Global Health Innovation Center predicts the world needs by the end of 2021.

James Krellenstein, a founder of PrEP4All and the author of its report, said “if they don’t change course pretty soon, the Biden administration is going to be remembered in terms that the Reagan administration is remembered today in not dealing with the AIDS crisis.”