[Newsdesk] Research in brief

Ensitrelvir is an oral inhibitor of SARS-CoV-2 protease approved in some countries for COVID-19 treatment. In a phase 3 randomized controlled trial, its efficacy as post-exposure prophylaxis was tested in household contacts of COVID-19 patients. A total of 2041 contacts with a mean age of 42.4 years were treated within 72 hours of symptom onset in the index patient. The group received either ensitrelvir (375 mg on day 1 and 125 mg on days 2–5; n=1030) or placebo (n=1011) for 5 days. The incidence of RT-PCR-confirmed COVID-19 in household contacts by day 10 was significantly lower with ensitrelvir (2.9%) compared to placebo (9.0%), with a risk ratio of 0.33 (95% CI 0.22–0.49; p<0.001). The results suggest ensitrelvir's efficacy in preventing COVID-19 transmission.