Smallpox is a serious, contagious, and sometimes fatal infectious disease. It is important to note that smallpox outbreaks have occurred from time to time for thousands of years, but the disease is now eradicated after a successful worldwide vaccination program.
There are two main types of smallpox.
- Variola major is the severe and most common form of smallpox, There are four types of variola major smallpox:
- ordinary (the most frequent type, accounting for 90% or more of cases);
- modified (mild and occurring in previously vaccinated persons);
- flat; and
- hemorrhagic (both rare and very severe
- Variola minor is a less common presentation of smallpox, and a much less severe disease, with death rates historically of 1% or less.
1. How long will I be protected after I get vaccinated?
Past experience indicates that the first dose of the vaccine offers protection from smallpox for 3 to 5 years, with decreasing immunity thereafter. If a person is vaccinated again later, immunity lasts longer.
2. In the past five years, have there been cases of smallpox?
No. In fact there has not been a case of smallpox in over twenty-plus years. The last case of smallpox in the world was in 1977.
3. If a smallpox attack were to occur today, would there be enough vaccine available for the entire United States?
Yes. However, most of the vaccine that's available is not licensed, which is one of the main reasons why it's currently not available to the general public.
4. How is smallpox spread?
Smallpox normally spreads from contact with infected persons. Generally, direct and fairly prolonged face-to-face contact is required to spread smallpox from one person to another. Smallpox also can be spread through direct contact with infected bodily fluids or contaminate objects such as bedding or clothing. Rarely, smallpox has been spread by virus carried in the air in enclosed settings such as buildings, buses, and trains. Smallpox is not known to be transmitted by insects or animals.
5. If someone is exposed to smallpox, is it too late to get vaccinated?
Vaccination within 2-3 days of exposure will completely prevent or significantly modify smallpox in the vast majority of persons. Vaccination 4-7 days after exposure likely offers some protection from disease or may modify the severity of the disease.
6. What are the effects of smallpox?
The majority of cases recover, but death may occur in up to 30% of cases.