Xocova (Ensitrelvir) Found to be Effective as a COVID-19 Postexposure Prophylaxis in Household Contacts
Nikhil Prasad Fact checked by:Thailand Medical News Team Jul 02, 2026 1 hour, 11 minutes ago
Medical News: A major international clinical study has found that Xocova (ensitrelvir), an antiviral drug originally approved to treat mild-to-moderate COVID-19, can also help prevent the disease in people living with an infected family member. The findings offer new hope for reducing household transmission, one of the most common ways SARS-CoV-2 continues to spread. This
Medical News report highlights evidence that the drug may become an important addition to COVID-19 prevention strategies.
A global Phase 3 trial shows that Xocova (ensitrelvir) significantly lowers the risk of COVID-19 among household
contacts when started soon after exposure.
Large International Trial Delivers Encouraging Results
The study was led by researchers from the University of Virginia School of Medicine, United States, together with investigators from multiple clinical research centers across the United States, Japan, and three other participating countries. The Phase 3 SCORPIO-PEP trial was conducted during 2023 and 2024 as a randomized, double-blind, placebo-controlled study involving household contacts of individuals recently diagnosed with COVID-19.
Participants had tested negative for SARS-CoV-2 before joining the trial and began treatment within 72 hours after symptoms appeared in the infected household member. They received either a five-day course of ensitrelvir or a placebo.
The modified intention-to-treat analysis included 1,030 participants receiving ensitrelvir and 1,011 receiving placebo. The average participant age was 42.4 years, approximately 37% had at least one risk factor for severe COVID-19 such as obesity, and nearly 10% were aged 65 years or older. More than 70% began treatment within 48 hours of exposure, allowing the antiviral to act before the virus became firmly established.
Significant Reduction in COVID-19 Risk
The primary outcome showed that only 2.9% of participants treated with ensitrelvir developed laboratory-confirmed symptomatic COVID-19 by Day 10 compared with 9.0% of those receiving placebo. This represents a remarkable 67% reduction in the risk of developing symptomatic infection.
Researchers also examined all SARS-CoV-2 infections, including those without symptoms. Only 14.0% of participants receiving ensitrelvir tested positive during follow-up compared with 21.5% in the placebo group, demonstrating a 34% reduction in overall household transmission.
These findings represent the first convincing evidence that an oral antiviral can be successfully used as postexposure prophylaxis against COVID-19 following household exposure.
Strong Safety Profile
The medication also demonstrated a reassuring safety profile. Adverse events occurred in 15.1% of participants receiving ensitrelvir and 15.5% of those receiving placebo. Serious adverse events were rare, occurring in only 0.2% of participants in each group. Importantly, there were no COVID-19-related hospitalizations or deaths during the
study. Researchers also noted that the drug did not commonly cause dysgeusia, an unpleasant alteration in taste that has been associated with certain antiviral medications.
The study excluded pregnant individuals, those recently vaccinated or recently infected with SARS-CoV-2, and people taking medications that could potentially interact with ensitrelvir.
Experts See New Opportunities
Lead investigator Dr. Frederick Hayden of the University of Virginia School of Medicine said the trial provides the first clear demonstration that an oral antiviral can offer strong protection when started soon after exposure to an infected household member.
Independent expert Dr. Tia Babu from the Department of Medicine, Division of Allergy and Infectious Disease, UW Medicine, United States, who was not involved in the research, described the findings as an important addition to available prevention measures. She emphasized that vaccination, masking, improved ventilation, and physical distancing remain essential, especially because treatment must begin quickly after exposure to achieve maximum benefit.
Researchers also suggested that ensitrelvir may prove particularly useful in nursing homes, long-term care facilities, and other congregate living environments where COVID-19 outbreaks can spread rapidly.
Conclusion
The SCORPIO-PEP trial demonstrates that early treatment with ensitrelvir after household exposure can substantially reduce both symptomatic COVID-19 and overall SARS-CoV-2 transmission while maintaining an excellent safety profile. Although additional research is needed in highly vulnerable populations and in real-world settings where early treatment may be more difficult to initiate, the findings indicate that Xocova could become the first widely adopted oral antiviral for postexposure prophylaxis, providing healthcare providers with an important new tool to protect families and reduce community spread.
The study findings were published in the peer reviewed journal: The New England Journal of Medicine.
https://www.nejm.org/doi/full/10.1056/NEJMoa2509306
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Read Also:
https://www.thailandmedical.news/articles/coronavirus
https://www.thailandmedical.news/articles/long-covid
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