In a study by drug company MSD (also known as Merck in the US), only 7.3% of patients who took the drug were hospitalized. 14.1% of patients given a placebo were hospitalized as well. While the drug awaits FDA approval, the US government already plans to purchase it en masse if it passes.
Molnupiravir has multiple benefits. It was originally created to treat equine encephalitis virus and showed promise against MERS and mouse hepatitis virus. It would also be the first oral treatment for COVID-19.
Trials done in India on patients did not show much promise. This discrepancy was partially due to the patients in question having moderate, not mild, COVID. Given the success of the MSD trials, molnupiravir seems to work best on milder cases of COVID, so it must be taken early.
MSD plan to make approximately 10 million courses of molnupiravir by the end of the year. While approval is still in the works, MSD claim they will apply for emergency use authorization.
Meanwhile, Gilead Sciences, Atea Pharmaceuticals and Pfizer are working on similar pills. Only after sufficient trials have taken place will researchers know which one is best. There is always the possibility that, given the short timeframe of creation and output, creators will have overlooked something important. This could be anything from a minor side effect to toxicity under certain conditions to production being ultimately unsustainable.
There is also the issue of global distribution. Molnupiravir, at about $700 per course, is simply too expensive for large parts of the world. The business dealings allow some distributors to set their own price, which mitigates the issue slightly. However, not all countries' medical systems can give the drug to people as soon as it is needed. In order for molnupiravir to be a workable solution, underlying social issues must be solved as well.