Quantifying the human impact of Melbourne's 111-day hard lockdown experiment on the adult population.

Lockdown was used worldwide to mitigate the spread of severe acute respiratory syndrome coronavirus 2 and was the cornerstone non-pharmaceutical intervention of zero-COVID strategies. Many previous impact evaluations of lockdowns are unreliable because lockdowns co-occurred with severe coronavirus disease related health and financial insecurities. This was not the case in Melbourne's 111-day lockdown, which left other Australian jurisdictions unaffected. Interrogating nationally representative longitudinal survey data and quasi-experimental variation, and controlling for multiple hypothesis testing, we found that lockdown had some statistically significant, albeit small, impacts on several domains of human life. Women had lower mental health (-0.10 s.d., P = 0.043, 95% confidence interval (CI) = -0.21 to -0) and working hours (-0.13 s.d., P = 0.006, 95% CI = -0.22 to -0.04) but exercised more often (0.28 s.d., P < 0.001, 95% CI = 0.18 to 0.39) and received more government transfers (0.12 s.d., P = 0.048, 95% CI = 0.001 to 0.24). Men felt less part of their community (-0.20 s.d., P < 0.001, 95% CI = -0.30 to -0.10) and reduced working hours (-0.12 s.d., P = 0.004, 95% CI = -0.20 to -0.04). Heterogeneity analyses demonstrated that families with children were driving the negative results. Mothers had lower mental health (-0.27 s.d., P = 0.014, 95% CI = -0.48 to -0.06), despite feeling safer (0.26 s.d., P = 0.008, 95% CI = 0.07 to 0.46). Fathers increased their alcohol consumption (0.35 s.d., P = 0.002, 95% CI = 0.13 to 0.57). Some outcomes worsened with lockdown length for mothers. We discuss potential explanations for why parents were adversely affected by lockdown.