COVID-19 is developing resistance to antivirals, but resistant strains remain rare

Embargoed until: Publicly released: 2024-09-26 01:00

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US scientists say COVID-19 is developing resistance to the antiviral drugs nirmatrelvir and remdesivir, particularly in immunosuppressed people, but resistant strains of the virus remain rare and fleeting. They looked for genetic changes in COVID-19 that allow it to outsmart nirmatrelvir or remdesivir in 156 people, 63 of whom were not treated with antivirals, and 79 of whom were. They found nirmatrelvir-resistant COVID-19 in nine people who received nirmatrelvir, and in two of those who did not. Among those treated with nirmatrelvir, people who were immunosuppressed had the highest frequency of resistance, the experts say. The genetic changes that confer resistance to nirmatrelvir were detected at low levels, in less than a fifth of the viral strains they looked at, and these tended to revert back to non-resistance later, the authors say. Resistance to remdesivir was only detected in two out of fourteen immunosuppressed people, and these genetic changes were also transient, reverting back to non-resistance quickly, the experts say. The findings suggest the risk of antiviral-resistant COVID-19 strains spreading in the community is low, they conclude.

Media release

From: JAMA

Emerging SARS-CoV-2 Resistance After Antiviral Treatment

About The Study: Treatment-emergent nirmatrelvir resistance mutations were commonly detected, especially in individuals who were immunosuppressed in this cohort study of 156 participants. However, these mutations were generally present at low frequencies and were transient in nature, suggesting a low risk for the spread of nirmatrelvir resistance in the community with the current variants and drug usage patterns.

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Journal/
conference: JAMA Network Open

Research:Paper

Organisation/s: Brigham and Women’s Hospital, USA

Funder: This work was supported by the grants U19 AI110818 and R01 AI176287 from the NIH, the MassCPR SARS-CoV-2 Variants Program, and the Massachusetts General Hospital Department of Medicine. Additional support was provided by the Ragon Institute BSL3 core, which is supported by the NIH-funded Harvard University Center for AIDS Research (grant No. P30 AI060354).

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