Temporary health shocks and persistent preventive behaviour: evidence from the MERS outbreak

Spikes in perceived health risks often induce preventive behaviours. However, it remains unclear whether such behaviours persist after risk perceptions return to normal levels. Using the unexpected and transitory health shock of the Middle East Respiratory Syndrome (MERS) outbreak in South Korea – which began in May 2015, peaked in June, and ended in July – we found that secondary school students washed their hands more frequently not only during the outbreak but also up to two years afterwards, compared to pre-outbreak years. We considered several explanations for this sustained behaviour, and the evidence is most consistent with a habit formation mechanism.