Information travels quickly. “Surprises“ tend to be few and far between or anticlimactic.
The world didn’t learn that there was a vaccine that could reduce likelihood of COVID infection in the same manner described above regarding polio. The world was incrementally exposed to daily/hourly progress reports of the vaccine development.
When approved under EUA policies, it was just the next logical and incremental step in a protracted series of events.
Fair enough. I was solely relying on the literal context of the quoted passage from Breakthrough, “...On April 12, 1955, the world learned that a vaccine developed by Jonas Edward Salk, M.D., could be relied upon to prevent paralytic poliomyelitis.” Thanks for the response.