COVID outcome may highly depend on viral exposure intensity.
For a specific person, a virus infection tends to be thought to have a predetermined outcome. For example, a young healthy person would be asymptomatic after Covid infection, and an old and sick person would die or be hospitalized. This explains most observations generally speaking. Since the start of the Covid 19 pandemic, a tremendous amount of data has been accumulated easing the verification of our hypotheses. The aforementioned all-or-none model has difficulty in explaining some data. For example, both New York City and South Dakota experienced large Covid waves in 2020 albeit at different times. They likely have 30-40% of their population infected. South Dakota's excess mortality (compared with 2019) is 23%, but the NYC's is 53%. Demographic difference unlikely can fully explain this difference. The current north-south divide in the US in terms the ▲ infection cannot be attributed to vaccination rate difference alone because Florida has a higher...