43 years after the eradication of smallpox, why haven’t we eliminated more infectious diseases?

Smallpox as a highly contagious disease

The mortality rate was abnormally high

Countless lives were taken

The World Health Organization announced the eradication of smallpox on its cover

But on October 25, 1979

For 2 consecutive years

After no new cases of naturally occurring smallpox occurred

Smallpox declared eradicated in humans

October 25th of each year is also designated as

"Smallpox Eradication Day"

How much do you know about smallpox

Smallpox is a highly contagious disease caused by the smallpox virus, which provides lifelong immunity after recovery. The smallpox virus is a type of poxvirus, brick-shaped in appearance, with strong resistance to dryness and low temperatures, and can survive on scabs and dust for several months to a year and a half.

Smallpox is one of the oldest and most lethal infectious diseases. There is no specific medicine to cure the infection, and patients will have pockmarks on their faces after recovery, hence the name "smallpox".

It is estimated that from 10,000 BC when smallpox may have appeared to the end of the 1970s when it was completely eradicated, it caused the deaths of at least 300 million people worldwide, causing serious disasters in human history.

Smallpox virus image source: China Medical Forum

The first vaccine

On May 14, 1796, British physician Edward Jenner discovered that people who had been infected with cowpox basically never got smallpox again. Does this mean that cowpox can be used to prevent and treat smallpox?

He found a person who had recently been infected with cowpox, collected pus from her skin, and injected it into a boy, who had a fever for several days but recovered uneventfully.

Two months later, Jenner vaccinated the boy with pus taken from the wound of a smallpox patient, but he did not show any symptoms, so Jenner believed that the vaccination against cowpox was effective.

Dr. Edward Jenner vaccinating a boy against cowpox

Image source: Science refutes rumors

Later, Jenner made several more attempts, and the results all showed that people who had been vaccinated with "cowpox" were immune to smallpox. He used this method to invent the first vaccine in human medical history.

The room where smallpox virus samples are stored has a striking slogan on the door

Image source: Science refutes rumors

Currently, the smallpox virus is only kept in two laboratories for research purposes: the Centers for Disease Control and Prevention in Atlanta, USA, and the State Research Center of Virology and Biotechnology in Novosibirsk, Russia.

Why haven’t we eliminated more infectious diseases?

First of all, the smallpox virus is a DNA virus, and a double-stranded DNA virus at that, which makes it almost impossible for it to mutate. The smallpox virus has only two subtypes in thousands of years of circulation, which ensures that as long as you get the cowpox vaccine, you will definitely gain immunity.

A special and fatal weakness of the smallpox virus made it destined to be the first target to be eliminated by humans: the human body is the only host. In other words, smallpox only infects humans and can only be spread and replicated between people.

Therefore, once all human beings have become immune to it, smallpox will have no place to survive and will inevitably become extinct.

Finally, although cowpox and smallpox are two completely different diseases, their pathogens, cowpox virus and smallpox virus, share cross-reactive antigens, which is why humans can be immune to smallpox by being vaccinated with cowpox, while cowpox is almost harmless to the human body.

From ancient times to the present

Our fight against disease has never stopped

Someone blew the whistle with his life

Someone went against the flow to save the dying and the wounded

Someone just recovered and donated plasma

May all diseases be conquered

May mankind always be healthy

Source: Science Refutes Rumors, Science Popularization China, China Medical Forum

Compiled by: Dong Xiaoxian and Cai Lin

END

Editor: Muzi