Budesonide’s antiviral effect against SARS-CoV-2 The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causal agent of coronavirus disease 19 (COVID-19), emerged in December 2019 in Wuhan, China, and continues to spread worldwide. Treatment options for COVID-19 are limited; therefore, antiviral drugs that efficiently reduce SARS-CoV-2 replication or alleviate COVID-19 symptoms remain urgently needed. Despite global vaccination efforts, the demand for effective antivirals against SARS-CoV-2 has remained high due to the continuous emergence of novel variants of concern (VoCs). Many of these VoCs have higher transmission rates and/or altered immune recognition. What is budesonide? Budesonide is a non-halogenated glucocorticoid that is a commonly used anti-inflammatory drug. Typically, budesonide is administered through the inhalation route to treat respiratory diseases such as asthma and moderate to severe chronic obstructive pulmonary disease (COPD).