A lot of research has been done around the world regarding Covid-19 and now Japanese researchers have found out why Covid-19 was so dangerous. He says that Coronavirus 2 (SARS‑CoV‑2), which causes Covid-19, contains an enzyme. Scientists focused on the role of a molecular tag named “ISG15” in the Covid virus. This prevents the nucleocapsid proteins from binding to each other—an important process for the virus to assemble.