It is a highly contagious disease caused by a virus from the orthopoxvirus family called Variola, whose infection has a high mortality rate; historically, it is believed to have killed more people than all other infectious diseases combined.
Although its natural incidence is considered eradicated since 1977, the date on which the last official case of smallpox, as a result of intense vaccination campaigns around the world, there is concern that from keeping samples of the virus, it could be used as a bioterrorism weapon.
There is no cure for smallpox nor specific treatments, so the vaccine is the only option to prevent it, but as it presents a high risk of serious side effects, its use is not justified except in people exposed to the virus.
There are two types of smallpox:
It is the traditional manifestation and it is the most serious. Its fatality rate is greater than 30%. It causes a systemic inflammatory reaction that causes organ failure and leads to death during the first 15 days of occurrence of the condition. Likewise, there is a risk of developing a more virulent variety called malignant or hemorrhagic, with symptoms worsening and bleeding in the skin and mucous membranes. It progresses rapidly, causing death in less than a week. About 10% of those infected with major smallpox can develop the hemorrhagic variety.
It causes the same symptoms as the major, but with less intensity. Its mortality rate is 1%.
The transmission mechanism of the virus can be:
- By direct contact through body fluids and through the air when coughing, talking, or sneezing.
- Through contaminated surfaces and objects.