Theoretically, which is why it was recommended to prescribe as a last choice for those who couldn't use, or didn't respond to, other treatments. - see mikeyouse

Theoretically, which is why it was recommended to prescribe as a last choice for those who couldn't use, or didn't respond to, other treatments. - see mikeyouse's comment. (Though that doesn't seem to be the only way it was prescribed.) The authors of the study haven't yet identified any molnupiravir-associated lineages that spread to more than 21 people.