From my understanding, fear of COVID variants is the worry that one could spread widely enough to equal 2020, totally untouched by current vaccines. I know that makes common sense, and I know a lot of very smart people are working to combat it, but what I’m not sure of (and I realize I’ve been making assumptions up to now) are the chances of a variant being totally unaffected by current vaccines, and thus the chances of another 2020 even after a large number of people are vaccinated worldwide. I know these things aren’t certain, but are there best guesses out there?
There’s a good reason that the spike protein is used as antigen for many of the vaccines - because spike has evolved to bind specifically to our ACE2 receptors to get into cells. A vaccine that uses the spike antigen will trigger a polyclonal immune response, meaning a variety of antibodies that target various parts of spike. So in order to evade all those antibodies completely, the virus would need to evolve a spike protein with a significantly different shape. But then new spike probably cannot bind so well to ACE2.
So the virus has a difficult problem in finding tweaks to spike that allow it to evade the immune response somewhat while still recognizing ACE2. It’s difficult for any new variant to evade completely.
So the disaster scenario of a variant for which the existing vaccines have no effect at all is unlikely. More likely is a quantitative decrease in efficacy. And in any case, modified mRNA vaccines to target the sneakiest variants can now be developed quickly. Then can be created in a couple of weeks, and as we get comfortable than small changes to known vaccines are unlikely to introduce great risk, the testing and approval process will probably shrink to a few months.
a month on, is there any more information about the effectiveness of the current vaccines with the variants? There are two variants spreading quickly in Canada, and I’m curious if the vaccine will still be effective against them?
The variants are reportedly pretty widespread in the US, but most of the new cases these days are middle-aged and younger. Older folks are underrepresented in the current stats - presumably because they’re the ones who have been vaccinated. This would seem to suggest that the vaccine is working quite well against the variants along with the original.
Another explanation is that the variants are more transmissible in younger people. In my area the age range proportions of cases have mostly stayed in the same order except <10 yr olds have moved up in their share of cases.
They appear to be more transmissible in everybody, not just young folks.
That’s what the models apparently say anyway.
Well, here’s an encouraging article:
It reports that the vaccines are long-lasting and also that they seem to be effective against variants.
Still a lot of research needed, as they get more real-life data from people who’ve had the vaccine over more than just six months, but encouraging.