Pandemic smallpox was responsible for 300–500 million deaths. As recently as the early 1950s, an estimated 50 million cases of smallpox occurred in the world each year. After successful vaccination campaigns throughout the 19th and 20th centuries, the WHO certified the eradication of smallpox in December 1979. To this day, smallpox is the only human infectious disease to have been completely eradicated, and one of two infectious viruses ever to be eradicated. Historically, measles was prevalent throughout the world, as it is highly contagious. According to the U.S. National Immunization Program, 90% of people were infected with measles by age 15.
Voluntary Human Extinction Movement be the best solution to the Earth's environmental problems. He believes that this idea has also been held by some people throughout human history. In 1991, Knight began publishing VHEMT's newsletter, known as "These Exit Times". In the newsletter, he asked readers to further human extinction by not procreating. VHEMT has also published cartoons, including a comic strip titled "Bonobo Baby", featuring a woman who forgoes childbearing in favor of adopting a bonobo. In 1996, Knight created a website for VHEMT; it was available in 11 languages by 2010. VHEMT's logo features the letter "V" (for voluntary) and a picture