[Smallpox and smallpox virus–200 years since the first vaccination in Norway].

The research article discusses the history of smallpox vaccination in Norway, beginning in 1801, the establishment of a vaccine institute and its effects on other animals, the eradication of smallpox, and the resurgence of cowpox in zoo animals, domestic pets, and humans.

Early Smallpox Vaccination in Norway

• The first smallpox vaccination in Norway was carried out in December 1801 with vaccine materials sourced from different countries such as Denmark, England, and Ireland, as well as from a few local cowpox cases.
• While the origin of the vaccine material was not the primary concern, the effect was the focus. There are indications that the variola virus, which causes smallpox, was used for human vaccination after it had passed through animals such as cows and horses.

Vaccine Institute and Effects on Animals

• In 1891, a vaccine institute was set up in Kristiania, Norway, for the production of vaccine in calves.
• Cowpox was initially a rare disease in cattle. However, 70,985 bovine cases were reported between 1889 and 1928. The rise in the cases was suspected to be a result of human vaccination against smallpox.
• Pox-like diseases were also registered in other animals including horses, pigs, sheep, goats, and dogs during that period.

Smallpox Eradication and Cowpox Resurgence

• Compulsory vaccination in Norway continued up to 1976, after which smallpox was eradicated.
• Despite the eradication of smallpox, there has been a resurgence of cowpox virus infections in the last few decades. This resurgence has been notably witnessed among zoo animals, domestic cats, and humans, with small wild rodents and shrews acting as wildlife reservoirs.
• The vaccinia virus, a type of poxvirus used in smallpox vaccine, has rekindled interest as a vector in recombinant vaccines.
• Given that the human population currently lacks immunity against orthopoxviruses and the potential new exposure through pets and wildlife, the authors suggest it would be valuable to consider the history of poxvirus in Norway and its relevance to the present situation.