Post-exposure #prophylaxis with #favipiravir among #household close contacts to confirmed #COVID19 cases: A cluster-randomized trial (PEPfavi)

 

Abstract

Background

Household transmission of SARS-CoV-2 remains a key driver of community spread, with secondary attack rates in Thai households reaching approximately 50 %. There is limited evidence supporting the efficacy of antiviral post-exposure prophylaxis (PEP) in this context.

Methods

The phase 2/3, open-label, (1:1) cluster-randomized controlled trial in Thailand, 168 household close contacts from 76 index cases were enrolled to receive either favipiravir-PEP (FPV-PEP) (1600–2000 mg/day for 7 days) or usual care. The efficacy of FPV-PEP was investigated in preventing SARS-CoV-2 infection after contact with index cases.

Results

The incidence of confirmed SARS-CoV-2 infection was lower in the FPV-PEP group than in the usual care group (7.32 % vs. 14.47 %), although the difference was not statistically significant. A trend toward fewer early positive rapid diagnostic test results on day 3 was observed in the FPV-PEP group. Symptom development was less frequent among FPV-PEP recipients, with fewer cases of fever, rhinorrhea, and myalgia. A significantly higher probability of remaining asymptomatic and delayed symptom onset was observed in the FPV-PEP group. No participants developed severe COVID-19 or required hospitalization.

Conclusion

FPV-PEP was associated with a lower incidence of fever, rhinorrhea, and myalgia among household contacts. While a reduction in secondary transmission was observed, it did not reach statistical significance. Further large-scale studies are warranted to clarify its role in preventing household transmission.

Source: 

Link: https://www.sciencedirect.com/science/article/pii/S1876034126000225?via%3Dihub

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Use of #Influenza #Antivirals to Prevent #Transmission

 

Abstract

Influenza antivirals play an important role in the prevention and control of influenza. We reviewed data on the effectiveness of influenza antivirals for reducing influenza transmission. We found that antiviral prophylaxis, whether given pre- or postexposure, has been shown to reduce the risk of symptomatic influenza in a variety of settings and populations. During pandemic responses, antiviral prophylaxis could play an important role, as demonstrated by the use of amantadine in the 1968–1969 influenza A(H3N2) pandemic and oseltamivir during the 2009–2010 influenza A(H1N1)pdm09 pandemic. Antiviral treatment reduces symptom severity, prevents complications, and can reduce onward transmission of infection. However, resistance, accessibility, and timing pose challenges. Future research directions include innovative therapies and combination treatments. Continued research and stewardship are crucial to optimize antiviral impact.

Source: Journal of Infectious Diseases, https://academic.oup.com/jid/article/232/Supplement_3/S215/8287908

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Efficacy of #baloxavir marboxil against #bovine #H5N1 virus in mice

Abstract

Since the first detection of highly pathogenic avian influenza (HPAI) H5N1 (clade 2.3.4.4b) in U.S. dairy cattle in early 2024, the virus has spread rapidly, posing a major public health concern as the number of human cases continues to rise. Although human-to-human transmission has not been confirmed, experimental data suggest that the bovine H5N1 virus can transmit via respiratory droplets in ferrets, highlighting its pandemic potential. With no vaccines currently available, antiviral drugs remain the only treatment option. Here, we investigate the efficacy of the polymerase inhibitor baloxavir marboxil (BXM) against this virus in mice. We find that early treatment post-infection is effective, but delayed treatment significantly reduces BXM efficacy and increases the risk of BXM resistance, underscoring the importance of timely BXM administration for effective treatment.

Source: Nature Communications, https://www.nature.com/articles/s41467-025-60791-5

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