Objectives: To assess the impact of COVID-19 on the mental health of SGO members during the first wave (W1) and second wave (W2) of the pandemic.Methods: During W1 and W2 of the COVID-19 pandemic (June 15 to July 1, 2020 and January 15 to 31, 2021), SGO members received an anonymous survey consisting of validated measures to assess for professional fulfillment and burnout (PFI), generalized anxiety (GAD-2), depression (PHQ-2), PTSD (IES-6), and novel questions regarding COVID-19 stressors. Univariate and multivariable analyses were utilized to determine associations between W1 and W2.Results: A total of 478 responses were recorded (23.3% response rate). Ninety-nine W2 responders who took both W1 and W2 surveys were excluded, leaving 379 total responses (W1: 254, W2: 125). The majority of responders were female (68.3%), aged ≤45 (55.7%), and non-Hispanic White ethnicity (69.9%). Overall, 16.1% and 14.0% reported a history of anxiety and depression, respectively. Personal COVID infections and institutional COVID burden were higher in W2 (p=0.01, p=<.0001), with 7.1% versus 15.2% infections and 31.1% versus 11.2% reporting low burden compared to 23.2% versus 42.4% reporting high burden. Positive screening for anxiety, depression, and PTSD was reported in 25%, 17%, and 61% of responders in W1, compared to 19.7%, 5%, and 31.4% in W2, respectively. In both W1 and W2, after adjusting for demographic covariates, low professional fulfillment was associated with anxiety (p-values <0.01), while burnout remained associated with anxiety, depression, and PTSD (p-values <0.04). No difference in overall burnout or professional fulfillment was found on a multivariable analysis comparing W1 and W2. With respect to low professional fulfillment, history of anxiety was found to be an independent modifier between W1 and W2 (p=0.03), as those with no preexisting anxiety (n=318) were 1.72 times more likely to have lower fulfillment in W1 versus W2 (95% CI: 1.02-2.92). Similarly, age was an identified modifier related to burnout between W1 and W2 (p=0.04), where those aged ≥ 56 years were 2.7 times more likely to endorse burnout in W1 versus W2 (95% CI: 0.84-8.63). Multivariable analysis of novel COVID-19 stressors (Table 1) demonstrated significantly higher levels of reported stress in W1 versus W2 due to change in work quality/deployment, current/potential PPE shortage, and significantly lower levels of stress regarding finances.Conclusions: Among 379 SGO members surveyed during W1 and W2 of the pandemic, burnout and low professional fulfillment remained prevalent in over 40% of members. Proportionately higher numbers of respondents endorsed low professional fulfillment, anxiety, depression, and PTSD in W1 versus W2, while the rate of burnout remained unchanged between the waves. Although no overall association was found between burnout and fulfillment in W1 and W2 on primary analysis, results of this study found that as the pandemic progressed into W2, older respondents (≥56) and those without a history of anxiety were more likely to have less burnout and higher professional fulfillment, raising important questions regarding potential determinants of resilience among healthcare workers. The trend towards improvement of professional fulfillment levels and stability in burnout levels between W1 and W2 may also provide important insight on SGO member wellness and its temporal associations in response to external stressors, while also highlighting the associations of burnout with pan positive screening for anxiety, depression, and PTSD, further adding to the ongoing need to address these mental health issues for our healthcare providers.