Serious viral infectious disease. Typical symptoms include skin pustules. Smallpox are a prime example of a successful immunization campaign: First attempts at creating a vaccine were made by Edward Jenner in the 1700's. He immunized patients using extracts from bovine smallpox which are caused by a closely related virus. Patients were immune to human smallpox following this vaccine. Mass immunizations led to smallpox being officially declared eradicated by 1980. Today, only two high-security laboratories store frozen viral cultures.