Was reading about the history of the Polio vaccine on Wiki. It seems promising vaccines with controversial results were available as early as 1935. Even the vaccines that eventually had widespread use had several safety incidents, including the famous Salk vaccine. I also learned that the vaccine used today was not the one developed by Salk but one with Soviet sponsorship by Sabin. This isn’t my field, and experts seem to be confident that a COVID-19 vaccine will be forthcoming shortly. One can’t help but think that there still isn’t a vaccine for, say, HIV, all these decades later.