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Nirmatrelvir–Ritonavir for Preventing Post–COVID-19 Conditions 

In a retrospective target trial emulation study of U.S. veterans following acute COVID-19, ritonavir-boosted nirmatrelvir reduced the frequency of just 1 of 31 potential post–COVID-19 conditions (PCCs), researchers report. “Only combined thromboembolic events [venous thromboembolism and pulmonary embolism] seemed to be reduced by nirmatrelvir–ritonavir,” the group concludes. “Our results suggest that considerations about PCCs may not be an important factor in COVID-19 treatment decisions.”

The study included nonhospitalized veterans in Veterans Health Administration care who were at risk for severe COVID-19 when they tested positive for SARS-CoV-2 in the first half of 2022. To simulate a randomized controlled trial of ritonavir-boosted nirmatrelvir, the investigators used 5 nested sequential trials with a 1-day duration to account for all 5 days after a positive test (i.e., days participants might have become eligible to start the drug product).

Based on a cumulative incidence of 31 potential PCCs at 31 to 180 days after treatment or a matched index date, the study showed the following: “Eighty-six percent of the participants were male, with a median age of 66 years, and 17.5% were unvaccinated. Baseline characteristics were well balanced between participants treated with nirmatrelvir–ritonavir and matched untreated comparators. No differences were observed between participants treated with nirmatrelvir–ritonavir (n = 9593) and their matched untreated comparators in the incidence of most PCCs examined individually or grouped by organ system, except for lower combined risk for venous thromboembolism and pulmonary embolism (subhazard ratio, 0.65 [95% CI, 0.44 to 0.97]; cumulative incidence difference, −0.29 percentage points [CI, −0.52 to −0.05 percentage points]).”

Source: Annals of Internal Medicine