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Letter to the Editor|Articles in Press

Molnupiravir and nirmatrelvir–ritonavir reduce mortality risk during post-acute COVID-19 phase

  • Eric Yuk Fai Wan
    Affiliations
    Centre for Safe Medication Practice and Research, Department of Pharmacology and Pharmacy, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
    Laboratory of Data Discovery for Health (D24H), Hong Kong Science and Technology Park, Hong Kong, China
    Department of Family Medicine and Primary Care, School of Clinical Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
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  • Boyuan Wang
    Affiliations
    Department of Family Medicine and Primary Care, School of Clinical Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
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  • Sukriti Mathur
    Affiliations
    Department of Family Medicine and Primary Care, School of Clinical Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
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  • Cheyenne I. Ying Chan
    Affiliations
    Department of Family Medicine and Primary Care, School of Clinical Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
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  • Vincent Ka Chun Yan
    Affiliations
    Centre for Safe Medication Practice and Research, Department of Pharmacology and Pharmacy, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
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  • Francisco Tsz Tsun Lai
    Affiliations
    Centre for Safe Medication Practice and Research, Department of Pharmacology and Pharmacy, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
    Laboratory of Data Discovery for Health (D24H), Hong Kong Science and Technology Park, Hong Kong, China
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  • Celine Sze Ling Chui
    Affiliations
    Laboratory of Data Discovery for Health (D24H), Hong Kong Science and Technology Park, Hong Kong, China
    School of Nursing, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
    School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
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  • Xue Li
    Affiliations
    Centre for Safe Medication Practice and Research, Department of Pharmacology and Pharmacy, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
    Laboratory of Data Discovery for Health (D24H), Hong Kong Science and Technology Park, Hong Kong, China
    Department of Medicine, School of Clinical Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
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  • Carlos King Ho Wong
    Affiliations
    Centre for Safe Medication Practice and Research, Department of Pharmacology and Pharmacy, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
    Laboratory of Data Discovery for Health (D24H), Hong Kong Science and Technology Park, Hong Kong, China
    Department of Family Medicine and Primary Care, School of Clinical Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
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  • Philip Hei Li
    Affiliations
    Department of Medicine, School of Clinical Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
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  • Chak Sing Lau
    Affiliations
    Department of Medicine, School of Clinical Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
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  • Ian Chi Kei Wong
    Affiliations
    Centre for Safe Medication Practice and Research, Department of Pharmacology and Pharmacy, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
    Laboratory of Data Discovery for Health (D24H), Hong Kong Science and Technology Park, Hong Kong, China
    Department of Pharmacy, The University of Hong Kong-Shenzhen Hospital, Shenzhen, China
    Aston Pharmacy School, Aston University, Birmingham B4 7ET, UK
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  • Esther Wai Yin Chan
    Correspondence
    Correspondence to: Department of Pharmacology and Pharmacy, Centre for Safe Medication Practice and Research, Li Ka Shing Faculty of Medicine, The University of Hong Kong, L02-56 2/F, Laboratory Block, 21 Sassoon Road, Pokfulam, Hong Kong, China.
    Affiliations
    Centre for Safe Medication Practice and Research, Department of Pharmacology and Pharmacy, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
    Laboratory of Data Discovery for Health (D24H), Hong Kong Science and Technology Park, Hong Kong, China
    Department of Pharmacy, The University of Hong Kong-Shenzhen Hospital, Shenzhen, China
    The University of Hong Kong Shenzhen Institute of Research and Innovation, Shenzhen, China
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Published:February 21, 2023DOI:https://doi.org/10.1016/j.jinf.2023.02.029
      Dear Editor,
      We read with great interest the recent article published in the Journal of Infection investigating the effectiveness of molnupiravir, nirmatrelvir–ritonavir, and sotrovimab in preventing hospital admission or death among COVID-19 patients.
      • Evans A.
      • Qi C.
      • Adebayo J.O.
      • Underwood J.
      • Coulson J.
      • Bailey R.
      • et al.
      Real-world effectiveness of molnupiravir, nirmatrelvir-ritonavir, and sotrovimab on preventing hospital admission among higher-risk patients with COVID-19 in Wales: a retrospective cohort study.
      We noticed that despite the use of broad-spectrum antivirals (e.g. remdesivir), monoclonal antibodies, corticosteroids, hydroxychloroquine
      • Agarwal A.
      • Rochwerg B.
      • Lamontagne F.
      • Siemieniuk R.A.C.
      • Agoritsas T.
      • Askie L.
      • et al.
      A living WHO guideline on drugs for covid-19.
      being attempted, only limited effectiveness was achieved in reducing mortality, along with financial and logistical limitations, preventing their widespread use. Hence, the pertinent question on whether the short-term evidence on the effectiveness of COVID-19 oral antivirals in reducing risk of mortality and hospitalizations holds true even in the post-acute phase, especially in a largely vaccinated global population in an Omicron-dominant setting, remains to be explored.
      • Ledford H.
      Long-COVID treatments: why the world is still waiting.
      Thus, by examining two cohorts of hospitalized patients from Hong Kong prescribed with either molnupiravir or nirmatrelvir–ritonavir, this longitudinal study aims to assess the benefits of both drugs in reducing all-cause mortality in COVID-19 vaccine recipients compared to non-recipients in an in-patient setting in the post-acute phase of infection.
      In this retrospective cohort study, electronic health records of eligible patients were extracted from the Hospital Authority (HA), vaccination records and COVID-19-confirmed diagnosis records from Department of Health (DH), and death-related records from the Hong Kong Deaths Registry. The validity and coding accuracy of all the databases have been evaluated in many previous high-quality epidemiological studies and COVID-19 pharmacovigilance studies.
      • Wan E.Y.F.
      • Wang Y.
      • Chui C.S.L.
      • Mok A.H.Y.
      • Xu W.
      • Yan V.K.C.
      • et al.
      Safety of an inactivated, whole-virion COVID-19 vaccine (CoronaVac) in people aged 60 years or older in Hong Kong: a modified self-controlled case series.
      • Wan E.Y.F.
      • Chui C.S.L.
      • Lai F.T.T.
      • Chan E.W.Y.
      • Li X.
      • Yan V.K.C.
      • et al.
      Bell's palsy following vaccination with mRNA (BNT162b2) and inactivated (CoronaVac) SARS-CoV-2 vaccines: a case series and nested case-control study.
      • Wan E.Y.F.
      • Mok A.H.Y.
      • Yan V.K.C.
      • Wang B.
      • Zhang R.
      • Hong S.N.
      • et al.
      Vaccine effectiveness of BNT162b2 and CoronaVac against SARS-CoV-2 Omicron BA.2 infection, hospitalisation, severe complications, cardiovascular disease and mortality in patients with diabetes mellitus: a case control study.
      All data were extracted with an anonymized personal identifier to protect patient confidentiality before performing analysis.
      Incidence rates and their corresponding confidence intervals (CIs) for each outcome were calculated based on the Poisson distribution. The association between COVID-19 antivirals and outcome occurrence was further estimated using the Cox proportion hazards regression model. Subgroup analysis was also conducted in subgroups stratified by age, sex, Charlson’s Comorbidity index, and number of vaccination doses received. Several sensitivity analyses were performed to test the robustness of the main results. All the analyses in this study were two-tailed, and results were considered statistically significant with a P-value< 0.05. R version 4.0.3 (www.R-project.org) was used for all statistical analyses. Two investigators (BW, CIYC) conducted the statistical analyses independently for quality assurance. STROBE (Strengthening the Reporting of Observational Studies in Epidemiology) statement checklists were followed to guide transparent reporting of the cohort study.
      For the analysis, 30,040 hospitalized patients with documentation of COVID-19 positivetest or prescription records of either of the two COVID-19 oral antivirals, between 26 February and 30 September 2022, were included (Supplementary Fig. 1). After a median follow-up of 172 days, 3758 events of mortality were recorded among participants. After fine stratification weighting, the lowest incidence rates (95% CI) for all the three outcomes were observed in nirmatrelvir–ritonavir recipients. The characteristics of patients in each group are displayed in the Table 1. Fig. 1 summarizes the incidence rates and the corresponding risks in the post-acute phase (i.e. 21 days after first COVID-19 positive test) associated with all-cause mortality in each group. Significantly lower risks of all-cause mortality were associated with both molnupiravir [HR (95% CI): 0.89 (0.81–0.98)] and nirmatrelvir–ritonavir [HR (95% CI): 0.72 (0.62–0.84)]. However, only nirmatrelvir–ritonavir recipients experienced significantly lower risks of A&E admission [HR (95%CI): 0.76 (0.70–0.82)] and hospitalization [HR (95% CI): 0.82 (0.76–0.88).
      Table 1Baseline characteristics of hospitalized COVID-19 patients after weighting.
      Non-recipientsMolnupiravir recipientsNirmatrelvir–ritonavir recipientsSMD
      Number of individuals17,28361536604
      Age, years72.58 (18.22)73.11 (17.15)72.65 (16.48)0.020
      Sex, male9090 (52.6)3304 (53.7)3464 (52.4)0.017
      Charlson Comorbidity Index4.26 (2.54)4.36 (2.35)4.23 (2.42)0.036
      Number of vaccinations received0.051
       05336 (30.9)2000 (32.5)2095 (31.7)
       1 dose of BNT162b2420 (2.4)143 (2.3)142 (2.1)
       2–3 doses of BNT162b22309 (13.4)871 (14.2)820 (12.4)
       1 dose of CoronaVac2579 (14.9)843 (13.7)987 (14.9)
       2–3 doses of CoronaVac6640 (38.4)2296 (37.3)2560 (38.8)
      Comorbidities
      Cancer1806 (10.5)666 (10.8)734 (11.1)0.014
      Chronic Kidney Disease1789 (10.4)687 (11.2)575 (8.7)0.055
      Respiratory disease1646 (9.5)580 (9.4)640 (9.7)0.006
      Diabetes4918 (28.5)1806 (29.3)1847 (28.0)0.020
      Cardiovascular disease10,387 (60.1)3779 (61.4)3901 (59.1)0.032
      Dementia697 (4.0)251 (4.1)252 (3.8)0.009
      Medication use within 90 days
      Renin-angiotensin-system agents6390 (37.0)2315 (37.6)2411 (36.5)0.015
      Beta-blockers5029 (29.1)1866 (30.3)1871 (28.3)0.029
      Calcium channel blockers8658 (50.1)3102 (50.4)3234 (49.0)0.019
      Diuretics4202 (24.3)1546 (25.1)1573 (23.8)0.020
      Nitrates2098 (12.1)776 (12.6)761 (11.5)0.022
      Lipid-lowering agents8045 (46.5)2912 (47.3)3025 (45.8)0.020
      Insulins3115 (18.0)1123 (18.3)1181 (17.9)0.007
      Antidiabetic drugs4550 (26.3)1644 (26.7)1777 (26.9)0.009
      Oral anticoagulants1538 (8.9)579 (9.4)580 (8.8)0.015
      Antiplatelets5811 (33.6)2132 (34.7)2245 (34.0)0.015
      Immunosuppressants593 (3.4)227 (3.7)242 (3.7)0.009
      Medication use within 7 days after COVID-19 diagnosis
      Tocilizumab57 (0.3)13 (0.2)19 (0.3)0.015
      Baricitinib122 (0.7)45 (0.7)77 (1.2)0.032
      Remdesivir1935 (11.2)751 (12.2)834 (12.6)0.030
      Interferon beta-1b241 (1.4)90 (1.5)88 (1.3)0.008
      ICU admission within 7 days after COVID-19 diagnosis356 (2.1)143 (2.3)166 (2.5)0.021
      Ventilatory support within 7 days after COVID-19 diagnosis413 (2.4)113 (1.8)133 (2.0)0.026
      All parameters are expressed in either frequency (percentage) or mean (SD).
      SMD = Standardized mean difference.
      Fig. 1
      Fig. 1Risk of all-cause mortality/hospitalization/A&E admission associated with different oral antiviral use at post-acute phase of infection. Incidence rate (cases/1000 person-years) with 95% confidence interval based on Poisson distribution. Hazard ratio with 95% confidence interval was obtained by Cox regression adjusted with weighting. CI = confidence interval; REF = reference level; A&E = accident and emergency.
      Fig. 2 illustrates the results from the subgroup analyses for each group. Similar patterns of mortality risk reduction were identified in association with drug recipients over non-drug recipients, largely consistent with the main analysis. Consistent findings were observed across sexes, Charlson Comorbidity Index scores and vaccination status, and in patients aged ≥65. However, among patients aged <65, no such benefits of risk reduction were associated with either drugs. Notably, the outcomes of hospitalization and A&E admissions followed a similar trend (Supplementary Fig. 5) and results from the sensitivity analyses were also largely consistent with the main analysis (Supplementary Figs. 2–4).
      Fig. 2
      Fig. 2Risk of all-cause mortality associated with different oral antiviral use in post-acute phase of infection within subgroups. Hazard ratio with 95% confidence interval was obtained by Cox regression adjusted with weighting. CI = confidence interval; REF = reference level; A&E = accident and emergency; CCI = Charlson’s Comorbidity index.
      The findings of this study demonstrate the survival benefits of both molnupiravir and nirmatrelvir–ritonavir in reducing COVID-19-associated risk of all-cause mortality among hospitalized patients during the post-acute phase of COVID-19 infection compared to non-recipients. This is in addition to reducing short-term risk of mortality and hospitalization in the acute phase of infection as demonstrated by previous studies. To the best of our knowledge, this study is the first to evaluate the real-world benefits of both oral-antiviral drugs (molnupiravir and nirmatrelvir–ritonavir) against COVID-19-associated mortality in an in-patient cohort of 20,000 hospitalized patients in the post-acute phase. The advantage of an in-patient setting supports the reliability of the systematic documentation of patient data as electronic health records recorded in the medical database by the HA, facilitating analysis of follow-up data. Further, including vaccinated and unvaccinated patients in the study cohort enabled evaluation of the effect of prior immunization and its potential interaction with antiviral benefits. By defining the inclusion period for patient recruitment to capture the Omicron-dominant infection outbreak, an up-to-date pandemic setting was more accurately represented, and association of drug-effectiveness against the newer subvariants could be evaluated. Nevertheless, several limitations underlie this study. Firstly, the usual limitation of inability to establish causality by observational studies affects the inference of the findings. Secondly, some potential confounders, including lifestyle factors, were unavailable and thereby unaccounted for in this study, although matching by age and sex and adjustment with a comprehensive list of confounders were conducted. Thirdly, the benefits of the drugs in vaccinated patients stratified further by number of doses or by type of vaccine (inactivated versus mRNA) were not examined, and the possibility of a dose–response relationship of vaccine with drug-effectiveness observed in previous studies
      • Yan V.K.C.
      • Wan E.Y.F.
      • Ye X.
      • Mok A.H.Y.
      • Lai F.T.T.
      • Chui C.S.L.
      • et al.
      Effectiveness of BNT162b2 and CoronaVac vaccinations against mortality and severe complications after SARS-CoV-2 Omicron BA. 2 infection: a case-control study.
      • Wan E.Y.F.
      • Mok A.H.Y.
      • Yan V.K.C.
      • Wang B.
      • Zhang R.
      • Hong S.N.
      • et al.
      Vaccine effectiveness of BNT162b2 and CoronaVac against SARS-CoV-2 Omicron BA. 2 infection, hospitalisation, severe complications, cardiovascular disease and mortality in patients with diabetes mellitus: a case control study.
      • Yip T.C.F.
      • Lui G.C.Y.
      • Lai M.S.M.
      • Wong V.W.S.
      • Tse Y.K.
      • Ma B.H.M.
      • et al.
      Impact of the use of oral antiviral agents on the risk of hospitalization in community coronavirus disease 2019 patients (COVID-19).
      • Wong C.K.H.
      • Au I.C.H.
      • Lau K.T.K.
      • Lau E.H.Y.
      • Cowling B.J.
      • Leung G.M.
      Real-world effectiveness of molnupiravir and nirmatrelvir plus ritonavir against mortality, hospitalisation, and in-hospital outcomes among community-dwelling, ambulatory patients with confirmed SARS-CoV-2 infection during the omicron wave in Hong Kong: an observational study.
      could not be ascertained. However, benefits of reduced risks in the post-acute phase associated with subgroups of unvaccinated and vaccinated patients were similar, indicating effectiveness of drugs irrespective of vaccination status.
      In conclusion, the findings of this study demonstrate the survival benefits of treatment with the COVID-19 oral antivirals, molnupiravir and nirmatrelvir–ritonavir, in reducing the risk of mortality in the post-acute phase in hospitalized patients, especially in older adults. These benefits are observed in both, vaccinated and unvaccinated patients. Moreover, treatment with nirmatrelvir–ritonavir may also be beneficial in lowering the likelihood of requiring hospitalization or A&E visits. Further study in larger cohorts (especially younger patients) is warranted.

      Data availability

      Data will not be made available to others because the data custodians have not given permission.

      Funding

      This work was supported by the Health and Medical Research Fund Research on COVID-19, The Hong Kong Special Administrative Region (HKSAR) Government (Principal Investigator (WP2): EWC; Ref No. COVID1903011); Collaborative Research Fund, University Grants Committee, the HKSAR Government (Principal Investigator: ICKW; Ref. No. C7154-20GF); and Research Grant from the Health Bureau, the HKSAR Government (Principal Investigator: ICKW; Ref. No. COVID19F01). ICKW and FTTL are partially supported by the Laboratory of Data Discovery for Health (D24H) funded by [email protected] administered by Innovation and Technology Commission.

      Ethics approval

      This study was approved by the Central Institutional Review Board of the Hospital Authority of Hong Kong (CIRB-2021-005-4) and the DH Ethics Committee (LM171/2021).

      Declaration of Competing Interest

      EYFW has received research grants from the Food and Health Bureau of the Government of the Hong Kong Special Administrative Region, and the Hong Kong Research Grants Council, outside the submitted work. FTTL has been supported by the RGC Postdoctoral Fellowship under the Hong Kong Research Grants Council and has received research grants from the Food and Health Bureau of the Government of the Hong Kong Special Administrative Region, outside the submitted work. CSLC has received grants from the Food and Health Bureau of the Hong Kong Government, Hong Kong Research Grant Council, Hong Kong Innovation and Technology Commission, Pfizer, IQVIA, and Amgen; and personal fees from PrimeVigilance; outside the submitted work. XL has received research grants from the Food and Health Bureau of the Government of the Hong Kong Special Administrative Region; research and educational grants from Janssen and Pfizer; internal funding from the University of Hong Kong; and consultancy fees from Merck Sharp & Dohme; Dohme, unrelated to this work. CKHW has received research grants from the Food and Health Bureau of the Hong Kong Government, the Hong Kong Research Grants Council, and the EuroQol Research Foundation, unrelated to this work. IFNH received speaker fees from MSD. ICKW reports research funding from Amgen, Bristol Myers Squibb, Pfizer, Janssen, Bayer, GSK, Novartis, the Hong Kong Research Grants Council, the Hong Kong Health and Medical Research Fund, the National Institute for Health Research in England, the European Commission, and the National Health and Medical Research Council in Australia, outside the submitted work; and is a non-executive director of Jacobson Medical in Hong Kong and a consultant to IQVIA and World Health Organization. EWC reports grants from Research Grants Council (RGC, Hong Kong), Research Fund Secretariat of the Food and Health Bureau, National Natural Science Fund of China, Wellcome Trust, Bayer, Bristol-Myers Squibb, Pfizer, Janssen, Amgen, Takeda, and Narcotics Division of the Security Bureau of the Hong Kong Special Administrative Region; honorarium from Hospital Authority; outside the submitted work. All other authors declare no competing interests.

      Acknowledgment

      We gratefully acknowledge the Department of Health and the Hospital Authority for facilitating data access.

      Appendix A. Supplementary material

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