Health and economic effects of COVID-19 control in Australia: Modelling and quantifying the payoffs of hard versus soft lockdown

Objective(s)Australia requires high quality evidence to optimise likely health and economy outcomes to effectively manage the current resurgence of COVID-19. We hypothesise that the most stringent social distancing (SD) measures (100% of level in Australia in April 2020) deliver better public health and economy outcomes. Design Fit-for-purpose (individual-based and compartment) models were used to simulate the effects of different SD and detection strategies on Australian COVID-19 infections and the economy from March to July 2020. Public reported COVID-19 data were used to estimate model parameters. Main outcome measuresPublic health and economy outcomes for multiple social distancing levels were evaluated, assessing "hard" versus "soft" lockdowns, and for early versus later relaxation of social distancing. Outcomes included costs and the timing and magnitude of observed COVID-19 cases and cumulative deaths in Australia from March to June 2020. ResultsHigher levels of social distancing achieve zero community transmission with 100% probability and lower economy cost while low levels of social distancing result in uncontrolled outbreaks and higher economy costs. High social distancing total economy costs were $17.4B versus $41.2B for 0.7 social distancing. Early relaxation of suppression results in worse public health outcomes and higher economy costs. Conclusion(s)Better public health outcomes (reduced COVID-19 fatalities) are positively associated with lower economy costs and higher levels of social distancing; achieving zero community transmission lowers both public health and economy costs compared to allowing community transmission to continue; and early relaxation of social distancing increases both public health and economy costs. SignificanceThe known is that COVID-19 infections can be suppressed with social distancing (SD) measures of sufficient stringency and duration. The new is we find highest levels of SD (100% SD that prevailed in April 2020) generate much lower COVID-9 deaths; reduced SD days; increased economic activity; and much higher probability of elimination over a subsequent 12-month period than lower levels of SD. The implications are that greater levels of SD are preferred to lower SD because they deliver both better public health and lower economy costs.