A brief history of smallpox
The Carlisle Mosquito Online

Friday, October 3, 2008


A brief history of smallpox

Smallpox. It was not long ago that the very word could evoke panic. Cities would empty as people tried to escape before they became infected with the highly contagious disease. Those who became infected (see “Lucy,” page 1) were helpless as the disease progressed, no treatment was available and with a death rate of about 30%, many watched as family and friends succumbed. Survivors were often left blind or permanently disfigured. It was not unusual for the entire population of a town or village to disappear, whether by fleeing or by death, as the untreatable disease ran its course.

One of the greatest scourges in history, smallpox, which is caused by the variola virus, is believed to have originated in African rodents and spread throughout the eastern hemisphere along trade routes, in the aftermath of wars and during the Crusades. Many historians believe that smallpox was first introduced to the Western Hemisphere by the Spanish and Portuguese explorers and that the heavy death toll due to smallpox infection led directly to the fall of the Incan and Aztec civilizations. Smallpox wreaked havoc throughout Europe and North America. During the 18th century, smallpox became the leading cause of death in Europe and, by the late 18th century, 400,000 Europeans died of smallpox each year.


Variolation was the first effective preventative against smallpox. A small amount of fluid from a smallpox lesion was applied to a scratch on a healthy person’s skin, which often resulted in a milder case of the disease and would render the patient immune to further infection.

“Taking the smallpox” became something of a social event. Close friends and relatives would prepare, be inoculated and spend the three-to-four weeks of quarantine together at a “smallpox party.” It is said that John Hancock’s wife was bitterly disappointed at Martha Washington’s decision to decline her “gracious invitation” and take variolation elsewhere. But because of religious and medical concerns, variolation was not completely embraced by the public. To many the concept of curing people by infecting them was unnatural and the risk immoral.

The smallpox vaccine

In 1796, Dr. Edward Jenner developed the first vaccine against smallpox. Jenner, an English country physician, had noticed that milkmaids who had been infected by cowpox did not contract smallpox. After years of observation and experimentation, Jenner determined that injecting a healthy individual with cowpox would protect him/her from developing smallpox. He coined the word “vaccination” (from Latin vacca, cow) to describe his cowpox inoculation. The British Royal Society rejected a paper in which Jenner described his vaccination experiments, calling his ideas “too revolutionary” and his experimental evidence “too limited.”

However, over the next 50 years, vaccination would become more popular in Europe and America. Since vaccination used cowpox rather than the more virulent smallpox virus, side effects were milder and a true smallpox infection was avoided. By 1800, more than 100,000 English had been vaccinated and in 1840 the British Parliament passed the Vaccination Act, mandating free vaccination of infants and outlawing variolation. Most Western governments adopted similar laws by 1900.

Epidemics in Boston

In Boston a series of smallpox epidemics began in 1677-1678 when approximately 20% of the city population died, only to be followed by epidemics in 1692, 1721 and 1752, each time resulting in significant loss of life. To escape infection, families fled the densely populated city for the countryside (including Concord/Carlisle, it is alleged) where they thought they would be safe from infection.

It was around 1800 when Dr. Benjamin Waterhouse first introduced Dr. Jenner’s smallpox vaccine to the United States. By 1855 the city of Boston had passed the first mandatory school vaccination law in the United States. As more states required school vaccination, the rate of smallpox infection in the United States continued to decrease. Infection rates remained high in Africa, South America and Asia, where vaccination was not as widespread.

During World War II, the smallpox infection rate was again on the rise. Travelers, immigrants and soldiers brought the virus home from other countries. From 1941 to 1946, the percentage of countries in which smallpox was endemic rose from 69% to 87%. During that period, smallpox killed three to four million people annually.

The last outbreak of smallpox in the United States was in February 1949. By 1972 the risk of vaccine complications far outweighed the risk of contracting the disease naturally and mandatory vaccination of school children against smallpox was ended. In 1980, after a vigorous vaccination campaign in South America, Africa and Asia, the World Health Organization declared smallpox officially eradicated.

Today smallpox is seen by many as just one in a long list of forgotten diseases. As Thomas Jefferson wrote in an 1806 letter to Jenner, “Future generations will know by history only that loathsome smallpox has existed, and by you has been extirpated.” ∆


Clark, Philip. Smallpox in Boston: A Complex Affair WGBH Forum. 2004. http://forum.wgbh.org/wgbh/forum.php?lecture_id=1707

Harvard University Library Open Collections Program:


Boylston, Zabdiel. An account of smallpox inoculated in New England. 1726.


Douglass, William. The abuses and scandals of some late pamphlets in favour of inoculating the smallpox. 1722. http://pds.lib.harvard.edu/pds/view/7910092?n=9&imagesize=1200&jp2Res=.25

© 2008 The Carlisle Mosquito