Proportionality and the need for evidence: A case study of outdoor public health interventions for respiratory viruses in Australia

Proportionality in public health ethics requires evidence that the expected benefits of public health interventions outweigh the expected harms. This chapter examines the relationship between proportionality and evidence requirements through a case study of mandatory outdoor interventions that were implemented during the COVID-19 pandemic in Australia. The analysis reveals that such policies were not proportionate, as there was minimal evidence of outdoor transmission risk and therefore minimal evidence of benefits of such interventions, while the policies imposed significant harms through liberty restrictions and punitive enforcement. Although uncertainty about a novel pathogen might justify initial precautionary measures, the proportionality principle requires public health agencies to collect data to demonstrate net benefit and reassess interventions as evidence accumulates. The chapter argues that more-restrictive policies, such as mandates with penalties, create an especially strong moral obligation to provide evidence of proportionality. The Australian case demonstrates how outdoor interventions persisted despite mounting evidence of their lack of proportionality. This analysis suggests that future use of outdoor interventions for respiratory viruses should face greater scrutiny and explicit evidence requirements.