PIP: Since May 1980 when the 33rd World Health Assembly declared the global eradication of smallpox, WHO has been developing a comprehensive system of surveillance aimed at maintaining the world permanently free from this disease. By 1984, all countries had ceased vaccinating the general public against smallpox, and had withdrawn the requirement for smallpox vaccination certificates from international travellers. A number of countries had also discontinued the vaccinating of military personnel. Until now WHO has maintained a stock of smallpox vaccine sufficient to vaccinate 300 million persons, but considering that 10 years have elapsed since the last endemic case of smallpox, maintenance of this reserve is no longer indicated. WHO continues to monitor rumors and coordinate the investigation of suspected cases, all of which have actually been misdiagnosed chickenpox or some other skin disease, or other errors in recording or reporting. Variola virus is now kept in only 2 WHO Collaborating Centers which possess high security containment laboratories. Since the variola virus gene pool has been cloned in bacterial plasmids which provide sufficient material to solve future research and diagnostic problems, there is no need to retain stocks of viable variola virus any longer. The results of a special program for the surveillance of human monkeypox have confirmed that the disease does not pose any significant health problem. In addition to testing human and animal specimens, WHO collaborating laboratories have made progress in the analysis of DNA of orthopoxviruses and in the development of reliable serological tests.