During the COVID-19 pandemic, healthcare workers were exposed to stressful and traumatic events, leading to negative mental health outcomes. This cross-sectional study in Italy surveyed 1,379 healthcare workers using an online questionnaire. The findings showed that being a frontline worker was significantly associated with post-traumatic stress symptoms (PTSS) ($p = 0.03$). Additionally, having a colleague who was sick, quarantined, or deceased was significantly associated with PTSS, depression, and higher perceived stress.