What part of the Chain of Infection was broken by the development of the Smallpox vaccine?

Without a chance to enter a new host, the disease is stopped cold. Breaking Link # 6: Resistant Host When the English doctor Edward Jenner developed a vaccine to prevent smallpox in 1796.

by going smokefree, you could improve the well-being of your friends, family, coworkers, and even your pets. here’s how the cigarettes you smoke affect the people around you.