Why was there opposition to Jenner about vaccination and inoculation?

Answer 1

Actually smallpox inoculation had been done for more than 3000 years before Jenner in India and other places. It involved using pustules from a recovering smallpox victim to induce what was hoped to be a mild case of smallpox and immunity. However sometimes inoculation caused a full blown case of smallpox with all the scarring and occasionally death. But people were familiar with it and felt they understood its benefits and risks.

Jenner introduced vaccination involving pustules from cows (in Latin vacca) with active cowpox. People were neither familiar or comfortable with this new method. Perhaps it might not produce immunity as effectively or long lasting as successful inoculation did. Might it produce unexpected side effects? Nobody (including Jenner) knew for certain and many rumors about vaccination began circulating.