How many deaths did smallpox cause?

The number of deaths caused by smallpox throughout history is estimated to be in the hundreds of millions. Smallpox was one of the most devastating infectious diseases in human history, with a mortality rate that could reach up to 30% in unvaccinated populations. The World Health Organization (WHO) estimates that smallpox caused between 300 and 500 million deaths in the 20th century alone. In 1967, the WHO launched a global smallpox eradication program, and by 1980, the disease had been eradicated worldwide.