01-29-2021, 03:15 AM
sekker has it right. The most likely explanation is -- unfortunately -- previously-undetected community spread.
That being said, it definitely IS possible for the same mutation to occur simultaneously and independently.
And... and this is a BIG "and"... there has been very little discussion so far of the possibility of viral swapping of mutations by way of simultaneous co-infection with different strains either of SARS-CoV-2 or of other coronaviruses which are quite common in the environment (typically giving more typical common cold/flu symptoms).
There HAS been some discussion of the fact that we may be inadvertently selecting for mutations with people who are infected for an extended period and then undergo various treatments which, for various reasons, may not be fully effective ... so then you are effectively selecting for mutations in the virus which help it evade the treatments. Somewhat akin to what happens when you don't use the full dose of an antibiotic on a bacterial infection and you end up selecting for some mutant form of the bacterium that has partial or full resistance to the antibiotic.
That being said, it definitely IS possible for the same mutation to occur simultaneously and independently.
And... and this is a BIG "and"... there has been very little discussion so far of the possibility of viral swapping of mutations by way of simultaneous co-infection with different strains either of SARS-CoV-2 or of other coronaviruses which are quite common in the environment (typically giving more typical common cold/flu symptoms).
There HAS been some discussion of the fact that we may be inadvertently selecting for mutations with people who are infected for an extended period and then undergo various treatments which, for various reasons, may not be fully effective ... so then you are effectively selecting for mutations in the virus which help it evade the treatments. Somewhat akin to what happens when you don't use the full dose of an antibiotic on a bacterial infection and you end up selecting for some mutant form of the bacterium that has partial or full resistance to the antibiotic.