i remember reading once that some European countries eliminated polio at the same time that it was eliminated in the U.S. but without the use of either vaccine. Is this true?
(Operating from memory here.)
Yes and no. There are a couple of three polio vaccines. Germany for example has long used a locally-developed vaccine thought to be less-effective than the two American-developed types. So Germany has managed to largely reduce polio, but without using the Salk vaccine.