@Brigitt73701323 That’s a good explanation of how mRNA vaccines (or shots, if you prefer) work. It seems to me that the reason you don’t want to call them “vaccines” is two-fold.
First, to do with the approach. Second, to do with the level of protection. 1/
First, to do with the approach. Second, to do with the level of protection. 1/
@Brigitt73701323 In the beginning, we had both live attenuated (weakened) and inactivated (real pathogen, but killed) vaccines. Examples of this are the smallpox vaccine (1798) and the anthrax vaccine (1904), respectively. 2/
@Brigitt73701323 Later, we started making vaccines that were just a single protein from the pathogen (diphtheria, 1942).
More recently, we have started to take approaches using engineered proteins (Hep B, 1982) sometimes assembled to look like viruses (HPV, 2008). 3/
More recently, we have started to take approaches using engineered proteins (Hep B, 1982) sometimes assembled to look like viruses (HPV, 2008). 3/
@Brigitt73701323 Then, of course, as we move to the present, we have the development of approaches like engineered adenoviruses (the J&J vaccine) or mRNA vaccines (Moderna, Pfizer). 4/
@Brigitt73701323 So we have diverse approaches to vaccination, reaching back centuries. But I would say that these are all vaccines, because they all raise an immune response that protects against infection or disease. 5/
@Brigitt73701323 In summary... lots of things we are happy to call “vaccines” are not actually live viruses. So I don’t think the fact that the mRNA vaccines (or shots) are not live should stop us calling them vaccines. 6/
@Brigitt73701323 Now to the second point. Can we call it a vaccine if it protects against disease, rather than infection?
The first thing to say is that there *are* things that we call vaccines that do this. The Hep B and rotavirus vaccines are examples of this. 7/
The first thing to say is that there *are* things that we call vaccines that do this. The Hep B and rotavirus vaccines are examples of this. 7/
@Brigitt73701323 But I think there’s a more important point here – about COVID vaccines preventing disease and transmission... 8/
@Brigitt73701323 You’re right that one big, obvious benefit is that they prevent severe disease. But for the mRNA vaccines, the way the trials were designed meant that we couldn’t know for sure that they also prevented infection. 9/
@Brigitt73701323 So it was completely reasonable when they were first released to say to people: keep being cautious, we don’t know yet if you could still catch it and pass it on. And obviously that would have been a disaster. 10/
@Brigitt73701323 But actually now we *do* have real-world evidence that the mRNA vaccines prevent not just disease but also infection, with more than 95% effectiveness. 11/
academic.oup.com/cid/advance-ar…
academic.oup.com/cid/advance-ar…
@Brigitt73701323 And of those <%% of people may still get infected, we also know that those people are less likely to pass on the virus than unvaccinated people. 12/
https://twitter.com/VikiLovesFACS/status/1387438362047524869?s=20
@Brigitt73701323 In summary... some vaccines do protect against disease, rather than infection. And to begin with, to be cautious, we assumed that the COVID vaccines might be similar. But actually, it’s better than we expected! 13/
@Brigitt73701323 Now, if you want to call it a shot, rather than a vaccine, that doesn’t really matter – clearly it *is* a shot! (... as well as being a vaccine.) The important thing is knowing all of this detail about what it does and doesn’t do. So hopefully this extra info is helpful! 14/14
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