Understanding how Victoria, Australia gained control of its second COVID-19 wave

• Published in: Nature communications 2021-11, Vol.12 (1), p.6266-6266, Article 6266
• Main Authors: Trauer, James M., Lydeamore, Michael J., Dalton, Gregory W., Pilcher, David, Meehan, Michael T., McBryde, Emma S., Cheng, Allen C., Sutton, Brett, Ragonnet, Romain
• Format: Article
• Language: English
• Subjects: 631/326/596/4130; 639/705/1042; 692/699/255/2514; 692/700/478/174; Adolescent; Adult; Coronaviruses; Coverings; COVID-19; COVID-19 - epidemiology; COVID-19 - prevention & control; COVID-19 - transmission; Epidemics; Estimates; Hospitalization; Humanities and Social Sciences; Humans; Middle Aged; Models, Theoretical; multidisciplinary; Physical Distancing; Protective clothing; SARS-CoV-2; Schools; Science; Science (multidisciplinary); Victoria; Young Adult
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-021-26558-4

During 2020, Victoria was the Australian state hardest hit by COVID-19, but was successful in controlling its second wave through aggressive policy interventions. We calibrated a detailed compartmental model of Victoria’s second wave to multiple geographically-structured epidemic time-series indicators. We achieved a good fit overall and for individual health services through a combination of time-varying processes, including case detection, population mobility, school closures, physical distancing and face covering usage. Estimates of the risk of death in those aged ≥75 and of hospitalisation were higher than international estimates, reflecting concentration of cases in high-risk settings. We estimated significant effects for each of the calibrated time-varying processes, with estimates for the individual-level effect of physical distancing of 37.4% (95%CrI 7.2−56.4%) and of face coverings of 45.9% (95%CrI 32.9−55.6%). That the multi-faceted interventions led to the dramatic reversal in the epidemic trajectory is supported by our results, with face coverings likely particularly important. The state of Victoria, Australia experienced a substantial second wave of COVID-19 but brought it under control with strict non-pharmaceutical interventions. Here, the authors model the second wave in Victoria to estimate the impacts of the different interventions.