Clinical effectiveness of oral antivirals for non-hospitalized adult COVID-19 patients aged 18-60 years.

Objective: To investigate the effectiveness of oral antiviral agents - nirmatrelvir - ritonavir or molnupiravir in non-hospitalized COVID-19 patients aged < 60 years.

Methods: This retrospective cohort study analyzed data of patients aged 18-60 years diagnosed with COVID-19 between 1 January 2022, and 30 June 2023. Propensity score matching was used to balance the demographic and clinical characteristics of patients receiving oral antivirals (nirmatrelvir - ritonavir or molnupiravir) and untreated controls. The primary outcome was a composite of all-cause emergency department visits, hospitalizations, or mortality within 30 days. The secondary outcomes included each individual component of the primary composite outcome.

Results: Two matched cohorts (antiviral group and control group) comprising 52,585 patients with balanced baseline characteristics were created using propensity score-matching. During follow-up period, the antiviral group demonstrated a lower risk of the primary outcome than the control group (hazard ratio [HR] 0.772, 95% confidence interval [CI] 0.736-0.808, p < 0.001). The antiviral group also exhibited a reduced risk of individual secondary outcomes, including emergency department visits (HR 0.780, 95% CI, 0.738-0.825), hospitalization (HR 0.755, 95% CI, 0.715-0.840), and mortality (HR 0.297, 95% CI, 0.147-0.600).

Conclusion: Oral antiviral agents were associated with lower risks of all-cause emergency department visits, hospitalizations, and mortality in non-hospitalized COVID-19 patients aged < 60 years.