Thread by @davidboxenhorn

1. What's so special about mRNA vaccines? A thread

Viruses (and all living things) are made of proteins. Our acquired immune system works by identifying one of the proteins of a foreign invader, and producing antibodies against that specific protein

https://twitter.com/davidboxenhorn/status/1379162552731639810

2. An autoimmune disease is when our body mistakenly identifies one of our own proteins as foreign, and produces antibodies against it

3. Until now, all vaccines were made from weakened or dead viruses, or related viruses that confer cross-immunity. Cross immunity can occur because related viruses often share proteins. Antibodies against a protein give you immunity from all viruses that share that protein

4. There are many potential problems with traditional vaccines. One problem is that weakened, dead, or related viruses might be harmful. Another is that viruses are very complicated (even though they are the simplest forms of life) and are made of a lot of proteins

5. With traditional vaccines, there is no guarantee that the body will produce antibodies against a good protein. It might choose a protein that's similar to one of yours, causing an autoimmune disease, or one that's not very important, that the virus can easily mutate around

6. The new mRNA vaccines bypass all of these problems. These vaccines produce a specific, carefully-chosen protein, not the whole virus.

Normally, your body makes proteins by using your DNA to create mRNA, and sending the mRNA to ribosomes, where the proteins are made

7. The way that viruses work is to produce their own mRNA, and send *that* to your ribosomes, which make copies of the virus, hijacking your protein-producing mechanism for their own purposes

8. The new mRNA vaccines do something similar. They also hijack your protein-producing mechanism, but not to produce whole viruses that can infect you. They only produce that one well-chosen protein (or a few) that we want you to produce antibodies against

9. In the case of covid, the mRNA vaccines target the "spike" protein. This protein produces the spikes that covid needs to attach to your cells. Without it, covid can't infect you. It's not easy to mutate around this protein - any mutation will likely produce ineffective spikes

10. If, by chance, a covid mutation happens to find another effective spike protein, it will be easy to add that protein to the vaccine, vaccinating against both forms of the virus

11. So, mRNA vaccines are a way to quickly and easily produce very effective, very targeted, and very safe vaccines, theoretically at will. We are already working on new ones, for example AIDS (above) and malaria

https://twitter.com/davidboxenhorn/status/1365927949132849154

12. Eventually, in the very-concievable future, we will be able to produce vaccines so effectively, and so fast, that we can target a disease that infects only a single person - cancer. (Cancer is a mutation of one of your own cells, each one is different)

https://twitter.com/davidboxenhorn/status/1355908523478102022

13. Now, I must end with one equivocation. I am a follower of @nntaleb and am very conscious of the problem of unknown unknows. This is new technology, and we have no experience with its long-term effects

14. Theoretically, there are no known problems, and it's clear that it's safe in the short term - hundreds of millions have already been vaccinated with very few major side effects

15. But we will only really know the long term when we get there. You never know when there might be a Black Swan