I've recovered from COVID19, why do I need a vaccine?

A recent study in the Lancet (a very prominent journal) found that, among a very young population in Qatar, the efficacy of “natural” infection was 95.7%. This is in line with other studies in Austria, Denmark, Qatar, Switzerland, the UK, and the US, which reported an efficacy of natural infection ranging between 80 and 95%.

So, do “naturally” infected …