What smallpox eradication can teach about new viruses

Thanks to science — and to cows — the world has been free of smallpox for more than 40 years, a fatal disease that has claimed hundreds of millions of lives. But how was it eradicated and what can be learned from this success?

May 8, 1980 was marked by one of the greatest achievements of science: the eradication of the smallpox virus. Before that, the disease shaped the course of human history, killing countless millions across the world. In the 20th century alone, the virus claimed an estimated 300 million lives.

After hundreds of years of intense scientific and public health efforts, the worldwide vaccination programs introduced in the 1970s put an end to the scourge of smallpox. But how was the world’s first vaccine developed? And why is it important that the immunizer remains stored and used in cases of monkeypox?

Cowpox – learning from popular culture

The scientific origins of the vaccine actually go back to folklore. In the 18th century, there were rumors that women who worked in milking England often caught mild cases of cowpox, but rarely contracted common smallpox.

Cowpox is a disease similar to smallpox but milder. Today it is known that it is transmitted by a virus of the same family, the so-called poxviruses.

When physician Edward Jenner heard about these stories, he began experimenting with cowpox in his own inoculation work. In the 1790s, Jenner used a needle to apply a dose of cowpox pus under the skin of a 9-year-old boy. When the boy was later exposed to smallpox, he appeared to be immune.

Jenner was not the first to use pus for protection against infections. Similar procedures had already emerged independently in many regions of the world, including Turkey, China, Africa, and India, as early as the 10th century. While Chinese doctors introduced a dry, ground sample of smallpox into the nose, Turkish and African doctors applied pus under the nose. skin, like Jenner. Although these methods were risky, people accepted a mild form of the disease and a low chance of death in exchange for protection against smallpox.

Despite its early origins, it was only after Jenner’s research that the medical and scientific world realized the role pus could play in preventing smallpox. The specialist’s work created a proven and less risky method of protecting against the disease, marking a turning point in its treatment.

Vaccination spreads

The demand for the vaccine spread around the world in the mid-to-late 19th century. In countries like England, Germany and the United States, inoculation was free for everyone and later became mandatory. High society women were eager to receive the immunizer and avoid the blemishes on the face typical of the disease, while those vaccinated or recovered could safely work with children.

Vaccination campaigns were also driven by economic factors. The aristocratic classes realized that smallpox outbreaks among the poor caused labor shortages. Advocating free vaccination for all was as much about protecting individual health as it was about protecting society’s wealth.

However, as today, inoculation programs were not celebrated by everyone. Many saw the low-life-threatening procedures as too risky, while religious opponents believed the vaccine interfered with God’s plans.

In the 19th century, anti-Semitic groups in Germany also claimed that immunizers were part of a global Jewish conspiracy to harm the German people. Similar anti-Semitic conspiracies have been observed in the more recent anti-vaccine movement, during the Covid-19 pandemic.

A modern vaccine

The modern smallpox vaccine was developed in the 1950s. More advanced scientific methods allowed the immunizer to be isolated and lyophilized for long-term storage and more easily distributed to locations around the world.

The new smallpox vaccine does not actually contain the smallpox virus, but the vaccinia virus, which is a different species, but closely related to the smallpox virus (both belong to the same family) and less harmful. Like inoculations against cowpox, vaccinia causes a small papule to develop on the skin, where the virus replicates. The body’s defense system then learns to recognize and destroy it.

Armed with this effective and safe method of combating smallpox, the World Health Organization (WHO) launched its first major eradication campaign in the 1950s, with the hope of achieving 80% vaccine coverage in each country.

The goal proved difficult, with vaccine availability and health infrastructure especially low in underdeveloped countries, where resources for public health programs of this scale were lacking.

Even so, the program was a great success. In 1966, smallpox remained endemic in only 33 countries. The last case of the disease occurred in Somalia in 1977. Three years later, the WHO declared smallpox eradicated.

Smallpox vaccine still useful today

Eradicating smallpox was perhaps one of humanity’s greatest achievements. It was a particularly deadly disease, with death rates of around 30% for the main virus. Many patients who survived were left with permanent sequelae and had to overcome debilitating symptoms, including fever, pain, exhaustion and vomiting.

Eradication meant the world could breathe freely again. But what can be learned from this success?

The smallpox vaccination effort has paved the way for several global immunization programs such as polio and Covid-19. That is, the world owes the remarkable speed and effectiveness of the vaccination program against the current pandemic to previous efforts against smallpox.

Sars-Cov-2, the coronavirus that causes Covid-19, was first identified in December 2019, and the first vaccine was approved for use a year later, in December 2020. Since then, global campaigns of Vaccination has been aimed at overcoming the problems of vaccine inequality to provide global protection against the virus.

Finally, despite the disease being eradicated, smallpox vaccines are still useful today to help protect against similar viruses, such as monkeypox.

The Imvanex smallpox vaccine is currently approved in Germany for those at risk of contracting monkeypox, but it is not recommended for the general population as experts say the disease is unlikely to turn into a pandemic. .