05/20/2026
Creator of the Newsletter, The Research Roundup, Shared news of a recent medical break through. Check out page to subscribe to their free newsletter.
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Hot off the presses from the New England Journal of Medicine with some good news! A new double-blind, randomized, placebo-controlled trial on Ensitrelvir (Xocova) a Japanese antiviral approved for treating COVID since 2022 (emergency approval) and then fully approved in 2024 has been studied and found to be successful as a post-COVID exposure prophylaxis. While it is not a silver bullet or 100% effective, it helps fill a gap that so many of us are in!
In this study of over 2,000 household contacts, 9% who received the placebo within 72 hours of their housemate developing symptoms and testing positive for COVID became symptomatic and tested positive as well. Whereas, only 3% who received the 5-day course of Ensitrelvir within 72 hours did.
Important caveats/a few limitations that are worth noting: the trial population was nearly fully some form of “pre-immune” (98%+ vaccinated or previously infected) and absolute infection rates were low overall. The drug also requires access within 72 hours of exposure and is not yet FDA-approved in the US, but we should get an updated on this in June. They also didn’t count asymptomatic cases - if they had it would be a 34% risk reduction rather than 67% reduction of symptomatic infections.
*I disagree with the second paragraph on the second slide as everyone is at risk for COVID/Long COVID but included to show how it is being marketed
Study: Ensitrelvir for Covid-19 Postexposure Prophylaxis in Household Contacts
DOI: 10.1056/NEJMoa2509306
🔗: https://www.nejm.org/doi/10.1056/NEJMoa2509306
Article: At last, a pill that can prevent COVID after exposure to infected people: Drug arrives years after pandemic’s peak, but could still offer protection to vulnerable populations.
🔗: https://www.nature.com/articles/d41586-026-01546-0