Originally posted by Juvenal
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Originally posted by carpedm9587
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We find that that optimal mitigation policies (combining home isolation of suspect cases, home quarantine of those living in the same household as suspect cases, and social distancing of the elderly and others at most risk of severe disease) might reduce peak healthcare demand by 2/3 and deaths by half.
R is the number of individuals an infected individual will infect. Infection is an exponential function of R. If R is greater than one, the spread will grow exponentially. If R is less than one, the spread will undergo exponential decay. Initially, at time zero, R is called R0.
The goal of mitigation or suppression policies is to reduce R.
Mitigation slows the spread by reducing R, but maintains exponential growth.
Suppression halts the spread by reducing R to less than one.
Mortality is the product of two factors, the infection ratio, which can be impacted by NPIs, and the infection fatality ratio. To change the infection fatality ratio requires pharmaceutical intervention, a palliative or a cure, both of which are attracting attention and funding, without notable success to date. So, until there's a vaccine, the goal is to reduce the infection ratio. Unmitigated, that ratio models out at 81 percent, or 2.2 million deaths in the US.
In the (unlikely) absence of any control measures or spontaneous changes in individual behaviour, we would expect a peak in mortality (daily deaths) to occur after approximately 3 months (Figure 1A). In such scenarios, given an estimated R0 of 2.4, we predict 81% of the GB and US populations would be infected over the course of the epidemic.
The principle benefit of mitigation policies is that they provide more time for infected individuals to recover, enhancing herd immunity, cutting the infection ratio in half and saving a million American lives but still allowing a million of us die. The principal benefit of suppression policies is that they can reduce mortality to levels comparable to the seasonal flu.
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