Hard to get herd immunity from something you can get multiple times and which seem to be more deadly subsequent times.
what's the evidence of this?
[1] https://www.vox.com/2020/7/12/21321653/getting-covid-19-twic...
Post infection, people seem to have robust neutralizing antibody responses and T cell immunity. Even if antibody responses are not measurably durable, latent B cell memory is _highly_ likely (e.g. antibody production restarts when the antigen is detected)
Antibody dependent enhancement seems to be unlikely given that the SARS-COV-2 spike protein seems relatively stable.
So once infected you are highly likely protected in the future.
That doesn't mean you can't be reinfected and be contagious... just that rather than go into full blown ARDS/sepsis, you would have a mild cold.