Thread by @DrKhorSK

The COVAX Facility aims to provide fair & equal access to the Covid vaccine for 7.8 billion people.

To commemorate 🇲🇾's entry into COVAX, I'll spend this week on some fun vaccine facts.

Fact 1: Edward Jenner discovered the concept of vaccination in 1796, ~220 years ago. (1/6)

For many years, he heard stories that dairymaids don’t get smallpox if they’ve had cowpox previously. Dairymaids spend a lot of time with cows to make milk or cheeses in a dairy.

This pic is cowpox. (2/6)

A young dairymaid had fresh cowpox. Jenner transferred some material from her skin lesions to an 8-year old boy’s skin. The boy had some mild fever but was otherwise quite well.

2 months later, Jenner repeated with smallpox but the boy had no fever.

This pic is smallpox. (3/6)

This proves the theory that “giving people very small amounts of a virus or bacteria can trigger their immune system to help fight future infections of the same virus or bacteria”.

This pic shows how vaccines work. (4/6)

The Latin word for cow is vacca, and cowpox is vaccinia.

Therefore, Jenner decided to call this new concept “vaccination”. (5/6)

Although… some historians think that Jenner used horsepox, not cowpox. So instead of vaccine, perhaps we should call it “equusine”!

This shows that science continues to progress, because our instruments & tools become more precise & sophisticated. 🧪🔬🧬💉 (6/6)

References:
1. ncbi.nlm.nih.gov/pmc/articles/P…
2. britannica.com/biography/Edwa…
3. ncbi.nlm.nih.gov/pmc/articles/P…
4. medlineplus.gov/ency/imagepage…
5. immunology.org/celebrate-vacc…
6. sciencemag.org/news/2017/10/w…