On May 20, 2020, Atossa Therapeutics announced the successful results from in vitro testing of AT-H201, Atossaﾒs proprietary COVID-19 drug candidate. The preliminary study results showed that AT-H201 inhibits SARS-CoV-2 infectivity of VERO cells in a laboratory culture, which are the standard cell types being used to study infectivity of the coronavirus. SARS-CoV-2, sometimes called the coronavirus, is the COVID-19 infectious agent.