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If the virus has mutated so much, shouldn't there be new vaccines? I'm kind of doubtful about the idea that delta, being different, means we need another dose

If the virus has mutated so much, shouldn't there be new vaccines? I'm kind of doubtful about the idea that delta, being different, means we need another dose of the vaccines that were developed for the original virus. In a few months, there may be something that is on beyond delta circulating. With flu, we expect the vaccines to be updated. The other issue I have is that my first shot (Pfizer) didn't bother me at all, but the second caused a lot of pain in my arm and a fairly short, but miserable overall feeling of illness. This contrasts with my experience of the flu shot, where the very first time, I felt almost as bad as the actual flu, for 1/5th of the time, but on subsequent years, had no reaction at all. What I'm saying is, two data points make a trend, even if not a terribly reliable one, and I don't have a good argument for why a third shot would not be as bad or worse. I think I've read that the reaction may be largely to inactive ingredients and not the vaccine itself. What does that mean? I don't know, but I can worry that the more times I'm exposed, the worse it will be. I've also read that the Moderna vaccine provided better immunity in retrospect, and you can probably choose whatever you want for your third. It seems like at the moment, cases are up, but fatalities are down. If I get the sense that half of the population has had a booster, or that vaccinated people are being hospitalized, maybe I will. Otherwise, I'm not in a rush.

nojokes 5y ago
Delta has improved in cell machinery and better cleavage site (point where its spike protein splits in half when entering the cell) but outside of it is well recognizable for current vaccine induced antibodies. There is no need for a new vaccine against it, just more antibodies to clear normally higher viral load that comes with it, so more of the same vaccine is better than something completely new. For data points, data from Israel states that third shot has been more tolerable than the second one in general with less frequent and less serious side effects. I will get mine in coming week and I can tell you about my personal experience - two previous shots gave me just pain in the injection site. Pfizer and Moderna chose a little different optimization strategy - Moderna went with higher mRNA dose (3x higher than Pfizer), Pfizer tested also smaller dose, saw that it produces about the same result but with less side effects and went with lower concentration. Now it appears that immunity from Moderna shot is longer lasting but it really does have more side effects than Pfizer. I think it is also the reason why the booster dosage of Moderna vaccine is half of its initial dosage. So perhaps it still will provide a little better immunity having about 1.5 mRNA concentration of Pfizer and has now about the same level of side effects. Hard to say at the moment.

nojokes 5y ago

Delta has improved in cell machinery and better cleavage site (point where its spike protein splits in half when entering the cell) but outside of it is well recognizable for current vaccine induced antibodies. There is no need for a new vaccine against it, just more antibodies to clear normally higher viral load that comes with it, so more of the same vaccine is better than something completely new. For data points, data from Israel states that third shot has been more tolerable than the second one in general with less frequent and less serious side effects. I will get mine in coming week and I can tell you about my personal experience - two previous shots gave me just pain in the injection site. Pfizer and Moderna chose a little different optimization strategy - Moderna went with higher mRNA dose (3x higher than Pfizer), Pfizer tested also smaller dose, saw that it produces about the same result but with less side effects and went with lower concentration. Now it appears that immunity from Moderna shot is longer lasting but it really does have more side effects than Pfizer. I think it is also the reason why the booster dosage of Moderna vaccine is half of its initial dosage. So perhaps it still will provide a little better immunity having about 1.5 mRNA concentration of Pfizer and has now about the same level of side effects. Hard to say at the moment.