With the coronavirus disease 2019 (COVID-19) pandemic causing unprecedented morbidity and mortality, the development of an effective antiviral drug for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has become a global health priority. Although many drug candidates have been identified via in vitro and in vivo models, there is a lack of consistent evidence from clinical studies, which may be due to the imperfect trial designs. The correct design of clinical trials for antiviral drugs is not well studied, especially concerning sample size calculation methodology.
