Published on
The Food and Drug Administration has approved ensitrelvir for the prevention of COVID-19 in individuals aged 12 years and older following exposure to SARS-CoV-2. According to the manufacturer, the authorization makes ensitrelvir the first oral antiviral available in the United States for postexposure prophylaxis against COVID-19. It must be initiated within 72 hours of exposure, and treatment includes a 5-day regimen. Approval was supported by findings from a trial including more than 2,000 participants that evaluated household contacts of individuals with COVID-19. In a modified intention-to-treat analysis, 2.9% of those receiving ensitrelvir developed COVID-19 within 10 days compared with 9.0% of those receiving placebo. Experts suggest the oral regimen may have applications beyond household exposures, including use following travel-related exposures and during outbreaks in healthcare settings. The Centers for Disease Control and Prevention estimates that between October 1, 2025, and May 23, 2026, there were 3.8 million–12.4 million new cases of COVID-19 in the United States, resulting in as many as 2.3 million outpatient visits and as many as 41,000 deaths.
Preventive measure: This U.S. approval of ensitrelvir is limited to postexposure prophylaxis and does not include treatment of active infection, according to manufacturer Shionogi & Co. Full prescribing information is available on the ensitrelvir website.