Objective: To assess longitudinal patterns of anxiety, depression, and posttraumatic stress symptoms, as well as their predictors, among workers at a referral hospital during the first two waves of the coronavirus disease 2019 (COVID-19) pandemic in Brazil. Methods: Data were collected between July 2020 and June 2021 (n=1,078). Anxiety, depression, and posttraumatic stress symptoms were assessed using three self-report scales: the Generalized Anxiety Disorder-7 (GAD-7), Patient Health Questionnaire-9 (PHQ-9), and Impact of Event Scale-Revised (IES-R). Predictor analysis included COVID-19-related events, fear of COVID-19, and institutional support. Statistical analysis involved linear mixed models (LMM) and local polynomial regressions. Results: Anxiety and depression trended towards increased reactivity, while posttraumatic stress presented a downward trend over follow-up, with less fluctuation. Predictor analysis showed that higher levels of institutional support were associated with a reduced risk of all adverse mental health outcomes; conversely, greater fear of COVID-19 was positively associated with all such outcomes. Conclusion: Our findings underscore the importance of allocating enhanced attention and resources to effectively addressing personal health challenges among the health workforce, emphasizing the significance of organizational support and continuous monitoring of emotional distress.