Annals of Internal MedicineEffectiveness of Nirmatrelvir–Ritonavir Against the Development of Post–COVID-19 Conditions Among US Veterans

A Target Trial Emulation

A recent study conducted among US veterans has explored the effectiveness of the oral antiviral treatment, nirmatrelvir–ritonavir, in preventing post-COVID-19 conditions (PCCs). The study provides valuable insights into the potential benefits of this treatment in a real-world setting.

Study Design

• The study was a retrospective target trial emulation comparing matched cohorts receiving nirmatrelvir–ritonavir versus no treatment.
• Participants were nonhospitalized veterans in Veterans Health Administration (VHA) care who were at risk for severe COVID-19 and tested positive for SARS-CoV-2 during January through July 2022.
• Eighty-six percent of the participants were male, with a median age of 66 years, and 17.5% were unvaccinated.

Key Findings

• The study examined the cumulative incidence of 31 potential PCCs at 31 to 180 days after treatment or a matched index date.
• No differences were observed between participants treated with nirmatrelvir–ritonavir and matched untreated comparators in the incidence of most PCCs examined individually or grouped by organ system.
• The only exception was a lower combined risk for venous thromboembolism and pulmonary embolism in the treated group (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]).

According to the World Health Organization, thrombosis is the third leading vascular diagnosis after heart attack and stroke, affecting between 300,000 to 600,000 Americans each year.

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