What Is The One Infectious Disease That Has Been Eradicated?

by | Sep 14, 2020

The variola virus causes the highly contagious smallpox infection

Humanity has eradicated just one infectious disease: Smallpox. Seriously? How about all those other horrible diseases that no longer seem to be an issue? They are still around.

Horrible Infectious Diseases That Still Persist

Polio? It’s mostly eradicated, but “still survives only among the world’s poorest and most marginalized communities, where it stalks the most vulnerable children.” Source

Bubonic Plague: It’s still around. According to the World Health Organization, “from 2010 to 2015 there were 3248 cases [of the plague] reported worldwide, including 584 deaths.” Additionally, about ten people contract the plague in the U.S. each year.

Tuberculosis: According to the WHO, “TB remains the world’s deadliest infectious killer” and 10 million people get TB each year and about 1.5 million people die from the disease.

Cholera: “Every year, there are 1.3 to 4.0 million cases of cholera, and 21,000 to 143,000 deaths worldwide due to the infection.” Cholera is spread by eating or drinking contaminated food or water. Source.

Leprosy: “There were 208,619 new leprosy cases registered globally in 2018.” Source.

AIDS: in 2017 nearly 1 million people worldwide died of HIV related illness and about 37 million people have HIV/AIDS. There were about 1.8 million new infections in 2017. Since the beginning of the HIV/AIDS epidemic in the early 1980s, 35 million people worldwide have died of the disease. IFOD on AIDS/HIV

Some Facts About Smallpox

For at least 3000 years Smallpox ravaged and devastated humanity. Smallpox killed an estimated 300 million people in the 20th century alone. Having a fatality rate of 30%, Smallpox was extremely deadly and also left survivors scarred from the pustules that formed on their skin. According to Jennifer Wright in her dynamite book Get Well Soon: History’s Worst Plagues and the Heroes Who Fought Them “smallpox makes your immune system go nuts . . . you die because your immune system kills you.” Prior to the development of a vaccine, there was no treatment for Smallpox.

How was smallpox eradicated? Even though a vaccine had been developed in the late 18th century, it took until the late 1970s to eradicate the disease. It was eradicated in rich countries by the mid-20th century but took decades more to rid the entire world of it. According to epidemiologist Tara Smith, there are four interrelated reasons why we were victorious against smallpox:

  1. “It’s a virus that only affects people, not animals. Wipe it out in humans, and that’s it, you’re done.”
  2. Unlike COVID, smallpox “infections are not asymptomatic: You can’t be infected and contagious but still appear healthy.”
  3. “Smallpox has a highly effective vaccine, made from a virus closely related to smallpox called the vaccinia virus. Because the vaccine contains a live virus, the immune system produces a rapid, strong and lasting response. The vaccine can even stop a smallpox infection in its tracks.”
  4. Finally, there is a big psychological reason: “Smallpox was a feared disease. People knew it was deadly, and even survivors could be scarred for life. This translated to political support from world governments and local support among populations receiving the vaccination.”

Comparing Smallpox to COVID and our chances of eradicating it: only factor one above — spreading only through humans — is currently true with COVID. Hopefully, we’ll have an effective vaccine in the future, but the lack of the other two factors will make eradication challenging.

Interesting fact: two samples of Smallpox still exist. The CDC has one and Russia has the other. Scarily, last year an explosion and fire occurred at the lab in Russia where it keeps its Smallpox sample.


The Tragic Death of Janet Parker

The last natural case of Smallpox occurred in Somalia in 1977, but three additional deaths occurred due to Smallpox in England in 1978. Janet Parker was a medical photographer at the University of Birmingham Medical School. She contracted Smallpox from the virus traveling through an air-duct from a lab below her office. She died of Smallpox four weeks after contracting it. Her father died “of the strain of being quarantined” and the doctor who ran the lab that allowed the virus to escape committed suicide. Source.


  1. Very interesting article, as always!
    I think it is very important to also look at her father’s cause of death. Isolation is obviously important in this case due to his (assumed) direct contact with his daughter, but taking away human interaction and routine is often just as harmful as the disease itself.
    In these past few months, spousal abuse, child abuse, overdoses, self-harm, and suicides have skyrocketed.
    This is NOT meant to be political or speak to what we did or didn’t do, it’s just food for thought.

    • The rise in the abuse and self harm seems intuitively obvious, but I have seen no data on it. Perhaps a topic for a future IFOD, or did I miss that one?


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