> The technique of cultivating a virus repeatedly in artificial media and isolating less virulent strains was pioneered in the early 20th century by Albert Calmette and Camille Guérin who developed an attenuated tuberculosis vaccine called the BCG vaccine.
> MMR is an attenuated (weakened) live virus vaccine. This means that after injection, the viruses cause a harmless infection in the vaccinated person with very few, if any, symptoms before they are eliminated from the body. The person’s immune system fights the infection caused by these weakened viruses, and immunity (the body’s protection from the virus) develops.
Oh, stop lying. https://en.wikipedia.org/wiki/Polio_vaccine
"The first successful demonstration of a polio vaccine was by Hilary Koprowski in 1950, with a live attenuated virus which people drank."
https://en.wikipedia.org/wiki/Attenuated_vaccine#History
> The technique of cultivating a virus repeatedly in artificial media and isolating less virulent strains was pioneered in the early 20th century by Albert Calmette and Camille Guérin who developed an attenuated tuberculosis vaccine called the BCG vaccine.
https://www.cdc.gov/vaccines/vpd/mmr/public/index.html
> MMR is an attenuated (weakened) live virus vaccine. This means that after injection, the viruses cause a harmless infection in the vaccinated person with very few, if any, symptoms before they are eliminated from the body. The person’s immune system fights the infection caused by these weakened viruses, and immunity (the body’s protection from the virus) develops.