There cannot be a the vaccine; obviously, SARS-CoV-2 vaccines will have to be updated. People will need boosters.

> I've still not heard a reasonable explanation about why this vaccine is expected to work long-term when the flu shot clearly does not

I don't think anyone in their right mind claims or believes such a thing, or believes that the health authorities are trying to convince them of such a thing. Depending on what we mean by "long term".

> SARS-CoV-2 mutates faster than the flu virus.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8137987/

"Compared with other RNA viruses such as HIV and influenza virus, SARS-CoV-2 accumulates mutations much more slowly (15, 28)."

So that would by why you can expect more mileage from SARS-CoV-2 vaccines.

>Especially since SARS-CoV-2 mutates faster than the flu virus.

This doesn't jive with what I have heard, that SARS-CoV-2 mutates rather slowly, like other coronaviruses.

And that the flu is completely different, having the ability to recombine parts, which is why we have a different strain every years, aka H1N1, H2N1, H2N2, etc. Every year they have to guess which one will be prevalent, therefore the yearly flu shots.

SARS-CoV-2 has not mutated into a different strain (variants are not strains), and is not expected to. Immune system response for other coronaviruses has been observed to be long lasting (17 years for SARS-CoV-1).

> Especially since SARS-CoV-2 mutates faster than the flu virus.

The SARS-cov-2 proofreading mechanism would like to have a word with your horribly inaccurate point