On May 8, 1980, the World Health Organization declared the eradication of smallpox, a disease that had plagued humanity for 3,000 years and killed approximately 300 million people in the 20th century alone.
It is worth noting that smallpox is considered one of the oldest infectious diseases known to humankind, as it claimed the lives of millions over thousands of years, and it is also the only disease that humanity has been able to eradicate completely.
Smallpox is caused by two types of viruses: the greater smallpox virus, which is the more deadly, with a mortality rate ranging from 20% to 40%, and reaching up to 90% in some severe outbreaks; and the less deadly smallpox virus, which has a mortality rate of between 1% and 3%. The disease is characterized by several symptoms, including fever, headache, lower back and limb pain, vomiting, and a rash on the skin and mucous membranes. After the rash heals, characteristic scars known as smallpox scars often remain.
The smallpox virus spreads through the air via coughing, sneezing, and talking, as well as through direct contact with contaminated surfaces such as bedding and clothing. The incubation period is usually between eight and fourteen days, but in some cases it can extend to nineteen days. In the past, smallpox caused a very high mortality rate; for example, it killed between 300 and 500 million people worldwide during the 20th century alone. Furthermore, approximately half of those who recovered suffered from vision problems, sometimes leading to complete blindness, and many were left with scars on the skin where the sores had previously been.
It is believed that smallpox may have been the cause of death of many rulers of ancient Egypt during the New Kingdom period, which spanned the 16th and 11th centuries BC, as evidenced by the distinctive marks that appeared on the skin of some mummies.
In the sixteenth century, smallpox reached the American continent from Europe, where it claimed the lives of millions of native people, leading to the extinction of some entire tribes there.
In 1796, the English physician and scientist Edward Jenner proved that infection with cowpox, a virus similar to smallpox but less dangerous, gives the body natural immunity against smallpox.
The global program to eradicate smallpox was launched in 1958, when the World Health Organization’s General Assembly adopted a resolution on the matter thanks to an initiative by the Soviet Union.
The last case of smallpox under natural conditions was recorded in 1977 in Somalia, and in 1980, the World Health Assembly at its thirty-third session officially declared the disease eradicated.
It is noteworthy that by 1936 the Soviet Union had managed to completely eradicate smallpox within its territory, thanks to a policy of compulsory vaccination and regular revaccination.
It is noted that the smallpox virus is still preserved globally in only two laboratories: the first is the Center for Virus Control in Novosibirsk, Russia, and the second is the Centers for Disease Control and Prevention in the United States of America.
One of the most devastating smallpox epidemics in history was the one that swept through Japan in the 8th century, killing up to a third of the population. Another epidemic claimed the lives of half a million people after the virus spread from French prisoners of war to civilians in Germany and other parts of Europe following the Franco-Prussian War of 1870–1875.
In a third devastating outbreak, smallpox killed nearly 4.7 million people in India between 1868 and 1907, while between 1926 and 1930 979,738 cases of the disease were reported, with a mortality rate of 42.3 percent.
The last outbreak of natural smallpox was in Somalia, where the last case was detected in October 1977, and after that, in December 1979, scientists concluded that smallpox had been completely eradicated from the face of the earth.
