A day after authorizing the emergency production of a first anti-COVID pill from Pfizer, the U.S. Food and Drug Administration has approved a second.

Merck’s pill, known as Molnupiravir, showed just a 30% efficacy of preventing hospitalization and death from COVID after symptoms start in clinical trials — compared to close to 90% from Pfizer’s Paxlovid pill — but it will go a long way in ending shortages amid the surge of Omicron.

The Pfizer pill, while more effective, is not as available. Its first shipment authorized by the federal government contains only enough for 65,000 treatments. The pill packs contain 30 tablets each, to be taken in a full treatment regimen over the course of five days.

By the end of the year, Pfizer hopes to have enough for 180,000 treatments, but not all of them could go to the U.S. The goal by mid-2022 is 30 million treatments, with the long-term goal of 120 million.

Merck will reportedly deliver hundreds of thousands of treatments for use over the same five-day cycle in the next couple days. Up to 1 million is said to be available in two weeks.

Molnupiravir also uses a different attack on COVID-19 compared to the Pfizer pill. Where the latter combines two drugs that interfere with the enzyme that makes copies of the virus and slow down the body’s metabolism, the Merck pill introduces mutations to the virus to fight its spread.

Some fear these mutations will contribute to more mutations of COVID-19 appearing in the wild, but tests provided to the FDA showed that occurrence was low.

The more important difference to take note of in regard to how the pills fight COVID, is that the Merck version will not interfere with other medication, while prescribing the Pfizer pill requires more consideration from doctors.

Still, it is not recommended for pregnant women to take both Pfizer and Merck’s anti-COVID pills.

The way the U.S. government seems to look at the approval, the more options available to fight the current surge in COVID-19 cases, the better.