The antiviral COVID-19 pills developed by U.S. firms are the next step in the pandemic battle.
However, some countries have raised concerns that shortages and manufacturing chaos could hamper the global supply, according to The Washington Post.
Wealthy countries have already advance-purchased much of the supply of treatments expected to be available in the first half of 2022.
A World Health Organization report produced earlier this month warns of a "high risk of shortages" of Paxlovid for low- and lower-middle-income countries until generic versions are more widely available, which it said was likely to be the second half of 2022, according to the Post.
Pfizer and Merck have reached deals to share the license for the drugs making generic versions available in India and Bangladesh.
While vaccines help to build immunity before infection, antiviral treatments such as Paxlovid and molnupiravir are used soon after symptoms appear.
Pfizer and Merck have shared the licenses for their drugs with the United Nations-backed Medicine Patent Pool, a nonprofit that aims to improve access to medicines, as well as with specific producers.
Under the agreement, each company would allow generic versions of the drugs to cover more than half of the world’s population, with Pfizer and Merck retaining the market control for high-income and upper-middle-income countries.
Drugmakers will need time to draw up manufacturing plans, with treatments still needing regulatory approval.