Here is the research the YouTube references https://www.nber.org/papers/w30512 I agree that there are problems within the methodology of the research and will look for more, however the data that was collected is quite stark and, if it is replicable across all areas in the USA then, as Anna points out in the video, may have played a part in the deciding the outcome of the last elections
I downloaded the PDF but haven't had a chance to read it yet. My initial thoughts are states like Florida are a red state so there are probably more republican voters. Also Florida probably has a higher percentage of older voters which are much more susceptible to covid. Thirdly republicans tend to have a higher proportion of senior voters just as democrats are more likely to win the Gen Z demographic. It seems boomers are much more likely to have comorbidities than Gen Zers.