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 Chronicle", Gregory Dicum states that there is an "undeniable logic" to VHEMT's arguments, but he doubts whether Knight's ideas can succeed, arguing that many people desire to have children and cannot be dissuaded. Stephen Jarvis echoes this skepticism in "The Independent", noting that VHEMT faces great difficulty owing to the basic human reproductive drive. At "The Guardian"s website, Guy Dammann applauds the movement's aim as "in many ways laudable", but argues that it is absurd to believe that humans will voluntarily seek extinction. Freelance writer Abby O'Reilly writes that since having children is frequently viewed as a measure of success,