J Korean Med Sci.  2023 Jul;38(27):e211. 10.3346/jkms.2023.38.e211.

Effectiveness of Paxlovid, an Oral Antiviral Drug, Against the Omicron BA.5 Variant in Korea: Severe Progression and Death Between July and November 2022

• Kim JM
• Yoo MG
• Bae SJ
• Kim J
• Lee H

• KMID: 2544413
• DOI: http://doi.org/10.3346/jkms.2023.38.e211

Abstract

Background
Paxlovid is an oral antiviral drug that received emergency use authorization in South Korea for the treatment of patients with mild-to-moderate coronavirus disease 2019 (COVID-19) on January 14, 2022. Since the onset of the severe acute respiratory syndrome coronavirus 2 pandemic, the virus has continued to evolve. The emergence of new variants has raised concerns about possible reductions in the effectiveness of vaccines and drugs. The effectiveness of Paxlovid in patients infected with the omicron variant and subvariants has not yet been determined. This study assessed the effectiveness of Paxlovid at reducing the risk of severe/critical illness or death and death in patients with mild-to-moderate COVID-19 caused by omicron subvariant BA.5.
Methods
In this nationwide retrospective cohort study, data on 8,902,726 patients were collected from four sources (the Drug Utilization Review database, COVID-19 Patient Information Management System, confirmed patient information, and basic epidemiological investigation data) between July 1 and November 30, 2022. Multivariable logistic regression analysis was conducted, with adjustment for age, sex, severe acute respiratory syndrome coronavirus 2 immunity (vaccination), and comorbidities.
Results
A total of 1,936,925 patients with COVID-19 were included in the analysis, including 420,996 patients treated with Paxlovid, and 1,515,959 patients not treated with Paxlovid. Paxlovid treatment in patients aged ≥ 60 years of age was associated with significantly reduced risk of severe/critical illness or death (46.0%), and death rate (32.5%), and its effectiveness was high, regardless of vaccination status.
Conclusion
Paxlovid is effective at reducing the risk of death due to COVID-19 in patients with omicron BA.5 infection, especially in older patients, regardless of vaccination status. This suggests that older patients with COVID-19-related symptoms should be administered Paxlovid, regardless of their vaccination status, to reduce severity and risk of death.

Keyword

COVID-19; Paxlovid; Omicron Variants; Oral antiviral drug

Figure

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  Fig. 1 Patient selection for the nationwide retrospective cohort study.COVID-19 = coronavirus disease 2019.

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  Fig. 2 Impact of Paxlovid treatment on severe/critical illness (with death) at subgroups. Multivariable logistic regression models were adjusted for age, sex, severe acute respiratory syndrome coronavirus 2 immunity (vaccination) and underlying diseases. Data are expressed as odds ratios (95% CIs).CI = confidence interval.

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  Fig. 3 Impact of Paxlovid treatment on death at subgroups. Multivariable logistic regression models were adjusted for age, sex, severe acute respiratory syndrome coronavirus 2 immunity (vaccination) and underlying diseases. Data are expressed as odds ratios (95% CIs).CI = confidence interval.

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