Researchers at the University of Uppsala in Sweden have found that nitric oxide (NO), which was successfully used to treat patients who contracted the first SARS-virus in 2003, also appears effective in treating SARS-CoV-2, the virus behind COVID-19.
Having an effective treatment is significant because while a vaccine is intended to prevent a person from becoming sick with a specific disease in the first place, it does not help to treat a person who is currently sick.
https://www.uu.se/en/news/article/?id=15422&typ=artikel&lang=en