New Drug Shows Promise in Preventing COVID-19 After Exposure

The drug, named "Ensiterivir," has been used to treat "COVID-19" in Japan since obtaining approval there, before later being approved as a preventive option as well.

Although the SARS-CoV-2 virus no longer imposes widespread lockdown measures as before, it still poses a risk to certain groups, especially the elderly and immunocompromised individuals. To date, antiviral drugs, such as Pfizer's "Paxlovid," are limited to reducing the severity of the illness after infection, without a proven effective treatment for prevention after direct exposure to the virus.

A study published in the New England Journal of Medicine revealed that "Ensiterivir," developed by Japanese company Shionogi, clearly reduces the likelihood of "COVID-19" infection after exposure to the virus, especially within homes where transmission is more common.

The study included over 2,000 people who lived with SARS-CoV-2 infected individuals. Half of the participants received the drug for five days, while the other half received a placebo, with neither participants nor researchers knowing which treatment was used.

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The results showed that "COVID-19" symptoms appeared in only 2.9% of those who took "Ensiterivir," compared to 9% in the placebo group within the first three days after exposure to the virus. Tests up to the tenth day also showed that 14% of the drug recipients were infected with the virus, versus 21.5% in the other group.

No significant differences in side effects were recorded between the two groups, as they were very close in percentage, with some minor effects such as temporary changes in cholesterol and blood lipid levels being noted.

Researchers pointed out that the study did not include certain cases such as pregnant women, nor did it take into account factors that could affect transmission within the home, such as household size or adherence to distancing.

Frederick Hayden from the University of Virginia, the lead researcher of the study, stated that the results represent the first strong evidence from an advanced clinical trial demonstrating the existence of an oral drug that can reduce the risk of "COVID-19" infection when taken after direct exposure to the virus.

The drug is expected to expand its scope of use to include prevention in other high-risk settings such as nursing homes, in addition to homes, although these uses were not directly tested in the study.

Japan had approved the commercial use of "Ensiterivir" under the name Xocova for treating mild to moderate cases of "COVID-19" in 2024, and later adopted it as a preventive treatment in 2026, in addition to similar approvals in Singapore.

The manufacturing company submitted a request to the U.S. Food and Drug Administration for approval in 2025, and a decision is expected in the coming period.

Source: Live Science