Interest in oral antivirals has surged in recent weeks. Merck (NYSE:MRK) announced on October 1 that the investigational antiviral molnupiravir appeared to halve the risk of hospitalization from COVID-19. Roche (SWX:ROG) and Atea (NSDQ:AVIR) are having less luck with the oral, direct-acting antiviral drug candidate AT-527. The two companies announced that the Phase 2 MOONSONG trial…