Ensitrelvir Effectively Prevents Spread of COVID-19 in Households
By Lori Solomon HealthDay Reporter
THURSDAY, March 20, 2025 -- For household contacts of individuals with COVID-19, taking ensitrelvir within 72 hours of symptoms is effective at preventing infection and generally well tolerated, according to a study presented at the annual Conference on Retroviruses and Opportunistic Infections, held from March 9 to 12 in San Francisco.
Akimasa Fukushi, M.D., of Shionogi & Co., Ltd, in Osaka, Japan, and colleagues randomly assigned household contacts (HHC) of index patients (IP) with COVID-19 to receive either ensitrelvir (1,030 participants; day 1: 375 mg; day 2 to 5: 125 mg) or placebo (1,011 participants) within 72 hours of symptom onset in the IP.
The researchers found that the overall proportion of HHC developing confirmed COVID-19 was significantly lower in the ensitrelvir group (2.9 percent) versus the placebo group (9.0 percent; risk ratio [RR], 0.33) for HHC with central laboratory-confirmed SARS-CoV-2 negativity by reverse transcription polymerase chain reaction (RT-PCR). For HHC regardless of central laboratory RT-PCR results at baseline, similar results were seen (RR, 0.43). Across both groups, the proportions developing treatment-emergent adverse events (TEAEs; 15.1 percent for ensitrelvir and 15.5 percent for placebo) or serious TEAEs (0.2 versus 0.2 percent) were similar, as were the TEAEs seen in >1.5 percent of patients in either group: headache (2.9 versus 2.5 percent), diarrhea (1.8 versus 1.3 percent), and influenza (1.1 versus 1.6 percent). No COVID-19-related hospitalizations or fatalities were seen.
"In addition to vaccination, postexposure prophylaxis with timely use of an oral antiviral would be a valuable way to help prevent COVID-19 illness in people who have been exposed, especially people at high risk for severe disease," presenting author Frederick G. Hayden, M.D., from the University of Virginia in Charlottesville, said in a statement.
The study was funded by Shionogi & Co., Ltd, the manufacturer of ensitrelvir.
Disclaimer: Statistical data in medical articles provide general trends and do not pertain to individuals. Individual factors can vary greatly. Always seek personalized medical advice for individual healthcare decisions.
© 2025 HealthDay. All rights reserved.
Posted March 2025
Further Support and Information on COVID-19
Read this next
Prevalence of Most Cancer Risk Factors Unchanged Before, After Pandemic
THURSDAY, April 24, 2025 -- Smoking rates continued to decline during the COVID-19 pandemic, but other major risk factors for cancer remained stable, according to a study...
Eviction Moratoria Reduced Child Maltreatment Rates During Pandemic
WEDNESDAY, April 16, 2025 -- Bans on evictions put in place during the COVID-19 pandemic seemed to reduce child maltreatment, according to a study published online April 8 in...
Hurricanes, Pandemic Led to Drop in CRC Incidence in Puerto Rico
MONDAY, April 14, 2025 -- Recent major events, including hurricanes Irma and Maria and the COVID-19 pandemic, were associated with a decreased incidence of colorectal cancer (CRC)...
More news resources
- FDA Medwatch Drug Alerts
- Daily MedNews
- News for Health Professionals
- New Drug Approvals
- New Drug Applications
- Drug Shortages
- Clinical Trial Results
- Generic Drug Approvals
Subscribe to our newsletter
Whatever your topic of interest, subscribe to our newsletters to get the best of Drugs.com in your inbox.