Understanding the dynamics and interplay of public support and adherence to five key mitigation behaviors over the course of the evolving COVID-19 pandemic.

Behavioral measures played a critical role in mitigating the COVID-19 pandemic, and their success hinged on continued public support and adherence. This study provides novel evidence on changes in support and adherence to behavioral mitigation measures and appraises the role of pandemic fatigue to provide robust guidance for effective governance of future public health and safety crises. Data were collected from a population cohort study in the Netherlands. This study used data from six assessments (December 2020-March 2022) at 12-week intervals, aligned with differences in pandemic severity and policy stringency. The analytic sample consisted of participants (N = 20,475) randomly allocated to answer questions on support and adherence to measures, focusing on physical distancing, avoiding crowds, mask-wearing on public transport, COVID-19 testing when symptomatic, and staying home when symptomatic. Changes in adherence and support and their interplay across time were assessed using random intercept cross-lagged panel models, controlling for age, gender and education. At the end of 2020, support for mitigation measures was found to be high, with little difference between measures. Subsequent changes in support for most measures broadly paralleled changes in pandemic severity and policy stringency. Adherence was less responsive to pandemic severity and policy stringency, and was mostly stable, albeit with differences between behavioral measures. Support and adherence to COVID-19 testing steadily increased after this was recommended as of early 2021. Changes in support and adherence did not reflect the notion of pandemic fatigue as a monotonic decline in support and adherence across behaviors. Findings highlight the need to better understand and address the factors influencing differing dynamics in support and adherence to specific protective behaviors.