Following the visit of a WHO Consultant, Pakistan in 1960 undertook a pilot project for the eradication of smallpox in Commilla and Faridpur (then the province of East Pakistan, now Bangladesh), the two worst affected districts during the 1957-58 great epidemic with a combined population of 7,6 million. In Commilla there were 13,594 cases and 9,750 deaths and in Faridpur 17,125 cases and 13,184 deaths. Between January and August 1961 the entire population of the two districts was vaccinated. Freeze-dried vaccine was used. The results were very encouraging. There was no case of smallpox in these two districts until the end of 1962. A small outbreak occurred in 1963 involving 444 cases in Commilla and 34 cases in Faridpur. By 1964 the disease had almost disappeared. Based on the experience gained in the pilot project, a comprehensive plan of smallpox eradication was made. The scheme provided complete protection of the total population of about 50 million to be achieved in two phases during the period from 1961 to 1972. During the first phase of the programme (by September 1963), over 40 million people were protected. Until 1958 the smallpox vaccine production laboratory in Dhaka was producing only wet vaccine but it switched over completely to freeze-dried vaccine. Calf was used in the production of the lymph. The laboratory produced 40 million doses per year which was quite enough to meet the requirements of the campaign. Samples of the vaccine were regularly tested. Some batches were sent to WHO for testing.
Research using live variola virus
The period since the eradication of smallpox has been defined by a continuing debate on the destruction of the last remaining stocks of live variola virus vs their retention for ongoing research for the benefit of humanity. Variola virus remaining in two high security laboratories consists of isolates of variola major and of the milder form, variola minor. The two repositories and research laboratories are: the WHO Collaborating Centre on Smallpox and other Poxvirus Infections at the US Centers for Disease Control and Prevention (CDC) in Atlanta, Georgia, USA; and the WHO Collaborating Centre for Orthopoxvirus Diagnosis and Repository for Variola Virus Strains and DNA at the Russian State Research Centre of Virology and Biotechnology (SRC VB VECTOR) in Koltsovo, Novosibirsk Region, Russian Federation.
On the advice of the Committee on Orthopoxvirus Infections, the World Health Assembly in 1996 made the decision to destroy all existing live variola virus stocks, including those held in the two repositories. However, the debate continued and the Health Assembly in 1999 authorized temporary retention of variola virus stocks and mandated the creation of the Advisory Committee on Variola Virus Research to oversee ongoing work and determine a date for destruction of stocks. Through further resolutions WHA55.15 (in 2002) and WHA60.1 (in 2007), and Decision WHA64.11 (in 2011), the Health Assembly authorized continuing retention for further essential research. Most recently, the Seventy-seventh World Health Assembly (in 2024) authorized continuing research to advance the development of countermeasures including diagnostics, vaccines and therapeutics for smallpox preparedness, acknowledged the additional benefit of this work for ongoing prevention and response for mpox and asked that such benefits be made available to all WHO Member States.