In particular, the USA employed a heterogeneous response, with different scales of quarantine measures (stay-at-home orders and business closures), despite the first reported case of COVID-19 occurring on 21 January 2020 in Washington state and cases being reported in all 50 states by mid-March. China gained rapid control of its epidemic, probably due to its rapid and strict lockdown as discussed in several studies, in contrast to several other countries with slower and less unified efforts.

The COVID-19 pandemic began in Wuhan, China and spread rapidly throughout the world in early 2020 provoking a wide range of interventions. We observe a theoretically predicted inverse proportionality relation between outbreak size and lockdown rate, with scale dependent on the underlying reproduction number and simulations suggesting a critical population quarantine ‘half-life’ of 30 days independent of other model parameters. Ultimately, we provide error-corrected estimates for commonly used metrics such as infection fatality ratio and overall case ascertainment for all 55 states and territories considered, along with the USA in aggregate, in order to correlate outbreak severity with first wave intervention attributes and suggest potential management strategies for future outbreaks. We estimate infection-level responsive lockdown/self-quarantine entry and exit rates (representing government and behavioural reaction), along with the true number of cases as of. In this study, via per capita testing dependent ascertainment rates, along with case and death data, we fit a minimal epidemic model for each state.

Each state in the USA exhibited a unique response to the COVID-19 outbreak, along with variable levels of testing, leading to different actual case burdens in the country.

Lockdown usa