A panel of U.S. health advisers on Tuesday narrowly backed a closely watched COVID-19 pill from Merck, setting the stage for a likely authorization of the first drug that Americans could take at home to treat the coronavirus.

The Food and Drug Administration panel voted 13-10 that the antiviral drug’s benefits outweigh its risks, including potential birth defects if used during pregnancy.

“I see this as an incredibly difficult decision with many more questions than answers,” said panel chair Dr. Lindsey Baden of Harvard Medical School, who voted in favor of the drug. He said FDA would have to carefully tailor the drug’s use for patients who stand to benefit most.