What caused smallpox in Victorian times?

Smallpox in Victorian times was caused by the variola virus. The virus was highly contagious and spread through direct contact with an infected person, or through contact with contaminated objects. The virus could also be spread through the air in small droplets when an infected person coughed or sneezed. As a result, smallpox was a common disease in Victorian Britain, with large outbreaks occurring throughout the 19th century, with estimates suggesting that at a point approximately 400,000 people succumbed to the virus throughout the century across Great Britain. Additionally, it is worth noting that before being eradicated, smallpox killed up to 30% of individuals that contracted it