Healthcare workers' heterogeneous mental-health responses to prolonging COVID-19 pandemic: a full year of monthly follow up in Finland.

Healthcare workers faced changing and heterogeneous mental-health challenges as the COVID-19 pandemic prolonged. Adversity and mental ill-being may have accumulated in some employees, and factors like living arrangements may have played a role. Knowledge on employees' demographic and socioeconomic background, as well as further research on the factors affecting employees' resilience, may help in maintaining healthy and efficient workforce in the face of a prolonging pandemic.