PreventionBy Mayo Clinic staff
To control the spread of the virus, people who have smallpox would be kept in isolation at a hospital. All the people they've had contact with would receive the smallpox vaccine, which can prevent or lessen the severity of the disease if given within three days of exposure to the smallpox virus.
The vaccine uses a live virus that's related to smallpox, and it can occasionally cause serious complications, such as infections affecting the heart or brain. That's why a general vaccination program for everyone isn't recommended at this time. The potential risks of the vaccine outweigh the benefits, in the absence of an actual smallpox outbreak.
If you were vaccinated as a child
It's not known how long immunity lasts after a smallpox vaccine. Studies to answer that question have had conflicting results. The duration of protection can be affected by the type of vaccine used and how it was administered.
It's likely that vaccination is most effective for about three to five years, with immunity decreasing after that. Partial immunity may last much longer.
- Smallpox disease overview. Centers for Disease Control and Prevention. http://www.bt.cdc.gov/agent/smallpox/overview/disease-facts.asp. Accessed June 6, 2011.
- Smallpox. World Health Organization. http://www.who.int/mediacentre/factsheets/smallpox/en. Accessed June 6, 2011.
- Friedman HM, et al. Smallpox. http://www.uptodate.com/home/index.html. Accessed June 6, 2011.
- Rotz LD, et al. Smallpox as an agent of bioterrorism. In: Mandell JE, et al. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. 7th ed. Philadelphia, Pa.: Churchill Livingstone Elsevier; 2010. http://www.mdconsult.com/books/about.do?about=true&eid=4-u1.0-B978-0-443-06839-3..X0001-X--TOP&isbn=978-0-443-06839-3&uniqId=230100505-57. Accessed June 6, 2011.
- Damon IK. Smallpox, monkeypox and other poxvirus infections. In: Goldman L, et al. Cecil Medicine. 23rd ed. Philadelphia, Pa.: Saunders Elsevier; 2008. http://www.mdconsult.com/das/book/body/191371208-2/0/1492/0.html#. Accessed June 7, 2011.
- Executive summary: Smallpox response plan and guidelines. Centers for Disease Control and Prevention. http://www.bt.cdc.gov/agent/smallpox/response-plan/files/exec-sections-i-vi.pdf. Accessed June 6, 2011.
- Isaacs SN, et al. Vaccinia virus as the smallpox vaccine. http://www.uptodate.com/home/index.html. Accessed June 7, 2011.