Abstract Title No Change in Endocarditis Rates in Patients with Congenital Heart Disease During the COVID-19 Pandemic Background Infective endocarditis (IE) is an infection of the endothelial layer of the heart with a yearly incidence of 10/100,000 in the general population, 25%-30% from healthcare related infections. Patients with congenital heart disease (CHD) have an increased risk for IE with a mortality rate of 19.4% at 6.7 years of follow-up. In 2025 there will be an estimated 355,000 adults aged 20-65 years of age with CHD. Poor dental hygiene and lack of preventive dental care are additional risk factors for developing IE. In March 2020, the ADA Health Policy Institute reported 76% of dental offices were only seeing emergency cases and 19% were completely closed, and importantly for the adult CHD population, Medicaid dental coverage was limited or eliminated in many states. We sought to investigate if the decreased access to dental care during the COVID-19 pandemic led to an increased burden of IE in the CHD population. Methods Retrospective review of a de-identified national administrative database (Vizient Clinical Data Base/Resource Manager) for hospitalized patients 2-80 years old with an ICD-10 code for any severity CHD between 10/1/2018 – 8/30/2022. Using the introduction of the ICD-10 code for COVID-19 (U07.1) in April 2020 to designate pre- and post-COVID time periods, two eras were defined: Era 1 (10/1/2018 – 3/31/2020) and Era 2 (4/1/2020 – 8/30/2022). Comparisons were made between endocarditis rates, demographics, length of stay, complication rates, in-hospital mortality and costs between Eras. Results There was a total of 264,126 admissions with CHD during the study period, 7,532 (2.9%) with CHD and IE. There was no difference in endocarditis rates between Eras (p = 0.478). The only differences identified were a slightly older age at admission in Era 2 (45 vs 47 years, p = 0.001) and higher costs in Era 2 ($48,952 vs 53,758, p = 0.017). Conclusion In this retrospective review of a large U.S. administrative database, we did not identify a significant change in IE hospitalization rates in CHD patients. While this finding is reassuring, it may not tell the complete picture yet. IE is a relatively rare condition with an annual incidence of 11/10,000 in the CHD population and can take months for symptoms to develop. Given the relatively short period available for study, there may not have been sufficient time with limited access to dental care to effect oral health enough and increase IE rates. It will be important for future studies to continue to assess this question.