To point 1, you’re right we don’t know for sure, but past experience with Coronaviruses (4 are endemic plus SARS and MERS) suggests that 0.5-3 years is not unre

To point 1, you’re right we don’t know for sure, but past experience with Coronaviruses (4 are endemic plus SARS and MERS) suggests that 0.5-3 years is not unreasonable. Past that the question becomes how much immunity, I.e. even if not completely immune, do you get a milder illness. Again we don’t know for sure but it’s a good Bayesian prior to assume yes, recovering from a legitimate SARS-COV-2 infection yields useful immunity for a meaningful period. For 2, it’s unlikely to mutate to the point of not being recognized within a relevant timeframe. We can track how fast it’s mutating reliably, and it’s not dangerously quick. The good news is if we have immunity, it should last for several years if considering only what we can see about the mutations. Follow the NextStrain project and Trevor Bedford on Twitter for a smarter analysis than I can provide here.