Smallpox was a highly contagious, usually fatal viral disease, prevalent throughout the world before the introduction of vaccination.

After a 12 day incubation period the first phase was marked by a high fever and three or four days later a rash appeared, normally on the face, the palms of the hands and the soles of the feet. During the next six to ten days the rash developed into pustular pimples.

The second stage of the disease was marked by a return of the high fever, during which the pustules could become further infected by bacteria.

As the recovery began the pustules would become crusted and the fever would start to subside. Severe scars, however, were often left on those who did manage to survive. In fact, few people did survive because the infection attacked the lungs, heart or brain. A person with smallpox was highly infectious from about the third day of the disease all through the erupting phase.

Due to the introduction of vaccination smallpox now appears to have been completely eradicated. However, as late as 1967, 10 to 15 million cases of the disease still occurred throughout the world. In that year the U N World Health Organisation (WHO) launched a worldwide vaccination programme against the disease and by 1979 there had not been a single case of smallpox anywhere in the world. The WHO declared that smallpox had been eradicated from the face of the earth.

Stocks of the virus still held in laboratories were ordered be destroyed by the WHO and all countries had to end vaccination programmes. In 1979 an English woman died after being contaminated with smallpox in a laboratory.

All stocks were not destroyed and small stocks still exist in the United States, Great Britain, Russia and China.

The total destruction of these last stocks is still an extremely controversial subject.