I don’t think it’s clear that mRNA flu vaccines will be as effective as mRNA corona vaccines.
One reason why SARS-CoV2 is an “easy” target for vaccine is that it has a very low mutation rate (as do other corona viruses). Influenza viruses evolve much faster. A standard problem of flu shots is that they are not designed against the virus that circulates in the winter, but rather against viruses that circulated half a year ago. For the corona virus, this does not make a big difference, but for flu viruses, it can render the vaccine (partially) useless.
The mRNA technology has some advantages because the cycle of development and production is shorter. But it is still long enough that the problem does not go away completely. We should not expect mRNA flu vaccines to be as effective as mRNA corona vaccines.
Flu shots already target 4 strains. The size of mRNA vaccines are so small that they could put 100 in one shot, but could the immune system handle it? But the short development time of mRNA vaccines means that they can target better. The same should be true of recombinant protein vaccines—the real promise of mRNA is that it’s new and sexy and the FDA will let them try. But targeting is only a small part of the flu vaccine problem. Good targeting raises the effectiveness from 30% in mismatch years to 50% in match years. The problem is the flu vaccine isn’t that good even when it is matched.
By late 2022 and much more probable by 2023 mRNA flu vaccines will be available and they will be just as effective as covid vaccines.
I don’t think it’s clear that mRNA flu vaccines will be as effective as mRNA corona vaccines.
One reason why SARS-CoV2 is an “easy” target for vaccine is that it has a very low mutation rate (as do other corona viruses). Influenza viruses evolve much faster. A standard problem of flu shots is that they are not designed against the virus that circulates in the winter, but rather against viruses that circulated half a year ago. For the corona virus, this does not make a big difference, but for flu viruses, it can render the vaccine (partially) useless.
The mRNA technology has some advantages because the cycle of development and production is shorter. But it is still long enough that the problem does not go away completely. We should not expect mRNA flu vaccines to be as effective as mRNA corona vaccines.
The big promise of mRNA technology is that a vaccine can be made against several strains in the same shot
Flu shots already target 4 strains. The size of mRNA vaccines are so small that they could put 100 in one shot, but could the immune system handle it? But the short development time of mRNA vaccines means that they can target better. The same should be true of recombinant protein vaccines—the real promise of mRNA is that it’s new and sexy and the FDA will let them try. But targeting is only a small part of the flu vaccine problem. Good targeting raises the effectiveness from 30% in mismatch years to 50% in match years. The problem is the flu vaccine isn’t that good even when it is matched.