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 human societies have not lived sustainable lifestyles, and attempts to live environmentally friendly lifestyles do not change the fact that human existence has ultimately been destructive to the Earth and many of its non-human organisms. Voluntary human extinction is promoted on the grounds that it will prevent human suffering and the extinction of other species; Knight points out that many species are threatened by the increasing human population. James Ormrod, a psychologist who profiled the group in the journal "Psychoanalysis, Culture & Society", notes that the "most fundamental belief" of VHEMT is that "human beings should stop reproducing", and that