The first to discover this method was the Turks. They discovered that when they were vaccinating their children against cowpox taken from cows, they did not get infected. In 1716-1718, the wife of the English ambassador, Mrs. Montagio, introduced that type of vaccination to England, Methods of the Ottomans in vaccination
An important topic thank you for that @reddust
There is a large argument that cowpox does not work because it is a disease from a different species and not related to human smallpox. The idea of vaccination was born on the back of old wives tales and superstition. At that time no one knew about our immune system, in fact science still doesn't know a whole lot about the immune systems. They just discovered gut bacteria are part of our immune system and vaccines are found to destroy gut bacteria...I wrote about this in my previous article thank you @hassanben
you welcome madam @reddust