The study did not show that Ivermectin killed SARS-CoV-2 viral particles. Prior to the pandemic, Ivermectin was known to act as an broad anti-viral. This is due to Ivermectin being a protease inhibitor, i.e. it blocks an enzyme from acting. It's important to note that this is the mechanism through which approved anti-virals for SARS-CoV-2, such as Paxlovid, operate.