The Recommendations (formerly Requirements) for Production and Control of Smallpox Vaccines were last revised in 1965. Since that time an intensified global eradication programme implemented from 1967 to 1980, and led by WHO, has resulted in the global eradication of smallpox. This was achieved by the globally coordinated use in national immunization programmes of effective vaccines that met the quality specifications in the 1965 Requirements. The last naturally occurring case of smallpox was reported in 1977. In addition to the availability of effective vaccines, an efficient infrastructure was established worldwide embracing the production, supply and administration of smallpox vaccine. Good surveillance, diagnosis of disease, training and public health information were additional important elements in successfully combating smallpox.
After human-to-human transmission of smallpox had been interupted worldwide the Global Commission that certified eradication was of the opinion that the likelihood of reintroduction of smallpox from laboratories or natural or animal reservoirs was negligible. Nevertheless it recommended that it would be prudent for WHO and national health authorities to be prepared for unforeseen circumstances. One measure was to ensure that adequate reserves of potent vaccine remained available. Accordingly a global stockpile of vaccine was established, as were national stockpiles. In addition seed lots of vaccinia virus suitable for the preparation of smallpox vaccine were maintained in a designated WHO collaborating centre. However in March, 1986, the Committee on Orthopoxvirus Infections concluded that the maintenance of a global reserve by WHO was no longer indicated, and interest in maintaining stocks repidly declined. A survey conducted by WHO in 2001 found that only small amounts of stockpiled smallpox vaccines still existed. These stocks are distributed quite unevenly around the world and are accessible to only a very selected part of the global population. Additional production would be needed to meet any major demand on vaccine supply such as might follow an intentional release of smallpox vaccine.
Global resumption of smallpox vaccine production would benefit from modern concepts of production and control, and modern regulatory expectations should be adhered to in the licensing process. These general principles should apply to new vaccine manufactured in embryonated eggs, or in primary or continuous cell lines, or animal skins. In addition, contemporary international reference materials to determine the potency of new vaccines and their immunogenicity in vaccinated individuals would be beneficial. The WHO Secretariat has followed these principles in producing this reformulated document and has included changes to bring the document into line with other WHO Recommendations published since the last revision.