Smallpox 1718. In 1721, Cotton Mather and colleagues provoked controversy in Boston by inoculating hundreds. In 1796, Edward Jenner, a doctor in Berkeley, Gloucestershire, rural England, discovered that immunity to smallpox could be produced by inoculating a person with material from a cowpox lesion. Cowpox is a poxvirus in the same family as variola. Jenner called the material used for inoculation vaccine, from the root word "vacca", which is Latin for cow. The procedure was much safer than variolation, and did not involve a risk of smallpox transmission. Vaccination to prevent smallpox was soon practiced all over the world. During the
To the Youth in Western Countries To the Youth in Western Countries On 29 November 2015, Ali Khamenei, the Supreme Leader of Iran, published an open letter addressed to the youth in western countries. It is the second letter of its kind, the first one having been published in January 2015. Both were distributed via his accounts on various social media, including Twitter, Facebook and Instagram, using the hashtag #CommonWorry. The second letter deals with Khamenei's views on the causes of recent terrorism. It was written in response to the November 2015 Paris attacks and other contemporary terrorist actions, such as the Metrojet Flight 9268 crash