[shmel]

How do you know this? mRNA vaccines are literally so new we don't know what will be in 2 years from now. They were never used in humans.

In comparison SARS survivors from 2003 still have immunity (I believe the same is with MERS).

[throwaway5752]

That isn't quite true. Since sars-covid-2 is new, it follows of course the specific vaccine is new. The RNA/mRNA approach goes back 30 years to HIV research, and the current vaccine has many years of research (directly from SARS-1 and MERS, and possible mitigations). A lot is known about them, regardless of widespread use. We will all undoubtedly learn more.

I'm not replying directly to you, but the duration of the immunity isn't terribly important past a certain point. The vaccine is much, much safer than infection. It prevents overwhelming of medical resources, and can reduce the community transmission levels to an extent that it can end a pandemic. Those are the primary benefits, not better or worse immune memory. That would just be a fringe benefit if it were the case.

[shmel]

Could you please name any other mRNA vaccine that was authorized for use in humans by FDA? I am not aware of any.

I agree that the vaccine is probably safer. However, propaganda that covid19 infection doesn't give you as good immune memory as the vaccine is outright false and should be considered as vaccine misinformation on major platforms.