Objectives: On November 5, 2021, Pfizer Inc. announced Paxlovid (nirmatrelvir +ritonavir) asa treatment method that could reduce the risk of hospitalization or death for patients withconfirmed coronavirus disease 2019 (COVID-19).
Methods: From February 6, 2022 to April 2, 2022, the incidence of COVID-19 and the effectsof treatment with Paxlovid were analyzed in 2,241 patients and workers at 5 long-term carefacilities during the outbreak of the Omicron variant of severe acute respiratory syndromecoronavirus 2 in South Korea.
Results: The rate of severe illness or death in the group given Paxlovid was 51% lower thanthat of the non-Paxlovid group (adjusted risk ratio [aRR], 0.49; 95% confidence interval [CI],0.24-0.98). Compared to unvaccinated patients, patients who had completed 3 doses of thevaccine had a 71% reduced rate of severe illness or death (aRR, 0.29; 95% CI, 0.13-0.64) and a65% reduced death rate (aRR, 0.35; 95% CI, 0.15-0.79).
Conclusion: Patients given Paxlovid showed a lower rate of severe illness or death and alower fatality rate than those who did not receive Paxlovid. Patients who received 3 dosesof the vaccine had a lower rate of severe illness or death and a lower fatality rate than theunvaccinated group.
Keywords: COVID-19; Effectiveness of vaccine; Omicron variant; Paxlovid.