Patient-Reported Adverse Events Among Elderly Patients Receiving Novel Oral COVID-19 Antivirals: A Nationwide Sampled Survey in Korea

There is a dearth of research on the factors linked with adverse events (AEs) associated with nirmatrelvir/ritonavir (NMVr) and molnupiravir (MOL), particularly in the elderly. Therefore, this study aimed to investigate self-reported AEs and identify factors associated with the occurrence of AEs following NMVr or MOL treatment among survey participants aged 60 years or older in South Korea. This nationwide survey was conducted through in-person interviews using structured questionnaires, from July 24 to August 31, 2023. Eligible participants included individuals aged 60 years or older who had been diagnosed with coronavirus disease 2019 (COVID-19) and received NMVr or MOL. The study outcomes included self-reported demographic, lifestyle, and health characteristics associated with the occurrence of AEs. Multivariate logistic regression analysis was used to estimate the adjusted odds ratio (aOR) and 95% confidence interval (CI) of each characteristic in participants with and without AEs. Of the 520 participants, 123 (23.7%) experienced at least one AE with oral COVID-19 treatment: 21.0% (96/458) for NMVr and 43.5% (27/62) for MOL. None of the participants reported any serious AEs. Increased odds of AE occurrence were observed in participants treated with MOL compared to those treated with NMVr (aOR, 3.05; 95% CI, 1.67-5.57), a history of two or more compared to one COVID-19 diagnosis (1.93; 1.03-3.62), and self-reported health status as "Unhealthy" compared to "Healthy" (2.65; 1.31-5.36). No AEs required further evaluation to change treatment strategies in elderly patients on NMVr or MOL. Several factors, including the use of MOL, history of COVID-19, and reported health status, were associated with an increased incidence of AEs. Both treatments may still be useful choices for patients with non-severe COVID-19 aged 60 years or older. However, close monitoring of unidentified potential harm and further investigation of the factors associated with the occurrence of AEs are needed.