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Does the size of a population make a difference in outcomes during an outbreak (US vs Italy, for example)?

We often talk about outbreaks in terms of the proportion of a population that is affected. Important factors in determining the proportion of a population that is affected include population density (the proximity of an infectious person to others influences disease transmission), public health interventions (which reduce the likelihood of exposure), and medical infrastructure/capacity (which determines our ability to treat and prevent death in those that are severely ill).

Population size does not directly impact the proportion of a population that will be affected. Factors that would determine proportion affected, especially when it comes to COVID-19, are the population's demographics (e.g. age and existing chronic medical conditions like heart disease, diabetes, lung disease, immune compromised).


Drafted 20 March 2020