Cross-sectional studies have shown that the COVID-19 pandemic has had a significant impact on the mental health of healthcare staff. However, it is less well understood how working over the long term in successive COVID-19 waves affects staff well-being.

To identify subpopulations within the health and social care staff workforce with differentiated trajectories of mental health symptoms during phases of the COVID-19 pandemic.

The COVID-19 Staff Wellbeing Survey assessed health and social care staff well-being within an area of the UK at four time points, separated by 3-month intervals, spanning November 2020 to August 2021.

Growth mixture models were performed on the depression, anxiety and post-traumatic stress disorder longitudinal data. Two class solutions provided the best fit for all models. The vast majority of the workforce were best represented by the low-symptom class trajectory, where by symptoms were consistently below the clinical cut-off for moderate-to-severe symptoms. A sizable minority (13–16%) were categorised as being in the high-symptom class, a group who had symptom levels in the moderate-to-severe range throughout the peaks and troughs of the pandemic. In the depression, anxiety and post-traumatic stress disorder models, the high-symptom class perceived communication from their organisation to be less effective than the low-symptom class.

This research identified a group of health service staff who reported persistently high mental health symptoms during the pandemic. This group of staff may well have particular needs in terms of the provision of well-being support services.

Throughout the coronavirus disease 2019 (COVID-19) pandemic, health and social care workers have faced unprecedented professional demands, all of which are likely to have placed considerable strain on their psychological well-being.

To measure the national prevalence of mental health symptoms within healthcare staff, and identify individual and organisational predictors of well-being.

The COVID-19 Staff Wellbeing Survey is a longitudinal online survey of psychological well-being among health and social care staff in Northern Ireland. The survey included four time points separated by 3-month intervals; time 1 (November 2020; n = 3834) and time 2 (February 2021; n = 2898) results are presented here. At time 2, 84% of respondents had received at least one dose of a COVID-19 vaccine. The survey included four validated psychological well-being questionnaires (depression, anxiety, post-traumatic stress and insomnia), as well as demographic and organisational measures.

At time 1 and 2, a high proportion of staff reported moderate-to-severe symptoms of depression (30–36%), anxiety (26–27%), post-traumatic stress (30–32%) and insomnia (27–28%); overall, significance tests and effect size data suggested psychological well-being was generally stable between November 2020 and February 2021 for health and social care staff. Multiple linear regression models indicated that perceptions of less effective communication within their organisation predicted greater levels of anxiety, depression, post-traumatic stress and insomnia.

This study highlights the need to offer psychological support to all health and social care staff, and to communicate with staff regularly, frequently and clearly regarding COVID-19 to help protect staff psychological well-being.