Stay-at-home policy: is it a case of exception fallacy? An internet-based ecological study

Savaris, R. F.; Pumi, G.; Dalzochio, J.; Kunst, R.

Background: Countries with strict lockdown had a spike on the number of deaths. A recent mathematical model has suggested that staying at home did not play a dominant role in reducing COVID-19 transmission. Comparison between number of deaths and social mobility is difficult due to the non-stationary nature of the COVID-19 data. Objective: To propose a novel approach to assess the association between staying at home values and the reduction/increase in the number of deaths due to COVID-19 in several regions around the world. Methods: In this ecological study, data from www.google.com/covid19/mobility/, ourworldindata.org and covid.saude.gov.br were combined. Countries with >100 deaths and with a Healthcare Access and Quality Index of [≥]67 were included. Data were preprocessed and analyzed using the difference between number of deaths/million between 2 regions and the difference between the percentage of staying at home. Analysis was performed using linear regression and residual analysis Results: After preprocessing the data, 87 regions around the world were included, yielding 3,741 pairwise comparisons for linear regression analysis. Only 63 (1.6%) comparisons were significant. Discussion: With our results, we were not able to explain if COVID-19 mortality is reduced by staying as home in ~98% of the comparisons after epidemiological weeks 9 to 34.