Smallpox: What the Dermatologist Should Know

Phyllis I. Spuls, MD; Jan D. Bos, MD, PhD; Donald Rudikoff, MD


Skinmed. 2004;3(4) 

In This Article

A Brief History of Smallpox and Vaccination

Smallpox was historically a scourge of mankind, responsible for numerous epidemics and untold morbidity and death.[6] Early attempts at control relied upon quarantine or variolation (inoculation), the actual introduction of material from smallpox exudates into those at risk of exposure to stimulate immunity.[7] Although the causative agent, a large, 150 x 260 nm, brick-shaped DNA orthopox virus, was only discovered in 1907, the technique of variolation was introduced in Europe during the early 18th century.[8] This technique, by provoking a limited case of actual smallpox, conferred lifelong immunity, but there was some risk of death to the recipient and of local outbreaks of variola.

In 1796, Edward Jenner, familiar with the inoculation technique, successfully vaccinated a boy using material from a milkmaid infected with cowpox.[9,10] In 1806, Napoleon introduced mass vaccination in France. The technique was introduced in the United States by Benjamin Waterhouse, who vaccinated his 5-year-old son with vaccine from England.[11] Vaccination rapidly spread to other northeastern cities, and President Thomas Jefferson had members of his own family vaccinated and actually performed many vaccinations himself.[11] Between 1820 and 1920, routine vaccination became the rule in the United States. The last known case of smallpox in the United States occurred in 1949 and routine vaccination was abandoned in 1972. The last naturally occurring case of smallpox was identified in 1977 in Senegal, but a subsequent case occurred following a laboratory accident in England.[12]

The only acknowledged remaining variola samples are sequestered in government laboratories in the United States and Russia. Besides controversy over whether these stores should be destroyed, there has been speculation that smallpox material may already be in the hands of other governments and possibly available to bioterrorists.

It is generally accepted that people exposed to smallpox can avoid life-threatening illness if vaccinated within 4 days of exposure.[13] Although individuals immunized before 1972 may still have some residual pro-tection,[14] discontinuation of routine smallpox vaccination has led to dwindling acquired immunity in the world's population. Variola is the only orthopoxvirus known to spread epidemically in humans but other existing ortho-poxvirus zoonoses (e.g., monkeypox, camelpox) could conceivably cause epidemic disease if they were genetically altered. Unaltered monkeypox can cause small outbreaks that are not self-sus-taining.[15] Although camelpox rarely spreads to humans, a severe generalized form can be fatal for animals. The camelpox virus genome resembles smallpox[16,17]and if genetically altered might pose a potentially serious threat.[18]

It is known that the former Soviet government cultivated a huge stockpile of variola virus for military use during the 1980s. Whether any of these stockpiles could have wound up in terrorist hands is a matter of conjecture.[19] The possibility that terrorist groups like Al Qaeda might use smallpox has lent new urgency to the worldwide issue of biosecurity. Dermatologists and primary care physicians would play a role in the recognition of index cases of smallpox, diagnosis and management of secondary cases, and the management of adverse reactions to the smallpox vaccine.[20,21]


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