Nirmatrelvir conferred protection in older adults during the Omicron outbreak

During the surge of the Omicron (B.1.1.529) variant, antiviral therapy with nirmatrelvir significantly reduced the rate of COVID-19-related hospitalization or death among patients aged ≥65 years, according to a recent study.

Using data from the Clalit Health Services database in Israel, the researchers retrospectively analysed 109,254 patients (mean age 59.9 years, 60.0 percent female) who were diagnosed with COVID-19 between January 9 and March 31, 2022. Of these, 3,902 patients were treated with nirmatrelvir, while the remaining 105,352 patients did not receive treatment with nirmatrelvir. The majority of the participants had previous SARS-CoV-2 immunity induced by vaccination, previous SARS-CoV-2 infection, or both. All patients were stratified according to age group: 40–64 years (n=66,433) and ≥65 years (n=42,821). [N Engl J Med 2022;387:790-798]

Among patients aged ≥65 years, those who received nirmatrelvir had a significantly lower rate of COVID-19-related hospitalization than those who did not receive nirmatrelvir (14.7 vs 58.9 cases per 100,000 person-days; adjusted hazard ratio [adjHR], 0.27).

In addition, fewer deaths due to COVID-19 infection occurred in nirmatrelvir-treated patients than those who were not treated with nirmatrelvir (2 vs 158 deaths; adjHR, 0.21).

Among those aged 40–64 years, COVID-19-related hospitalization rate was 15.2 vs 15.8 cases per 100,000 person-days (adjHR, 0.74) in the nirmatrelvir group vs the untreated group, while the death rate was 1 vs 16 deaths (adjHR, 1.32). “No evidence of benefit was found in [this patient population],” noted the researchers.

“Our study suggests that during the Omicron [variant] surge, … among adults [aged] ≥65 years of age, the rates of severe COVID-19 outcomes were significantly lower among those who received nirmatrelvir than among those who did not receive nirmatrelvir,” said the researchers.

“[However,] it should be noted that the evaluation of adverse events and safety data reports was beyond the scope of this study,” they said. “Future studies will be needed to assess the short- and long-term safety of nirmatrelvir treatment in real-world settings.”

“Treatment with nirmatrelvir is currently recommended by the National Institutes of Health (NIH) as the first choice for antiviral therapy for nonhospitalized adults who are at high risk for disease progression, regardless of vaccination status. [https://www.covid19treatmentguidelines.nih.gov/management/clinical-management-of-adults/nonhospitalized-adults--therapeutic-management/]