398. Increased Risk of Severe COVID-19 Outcomes Across all Groups of Individuals with Hematological Malignancies, Solid Tumors, and Solid Organ Transplants Compared with the General Population: Initial Results from INFORM, a Retrospective Health Database Observational Study in England

Abstract Background Despite COVID-19 vaccination, individuals who are immunocompromised due to underlying conditions, such as cancer and organ transplant, are at a greater risk of severe COVID-19 outcomes compared with the general population that is vaccinated. However, there are limited data quantifying this risk during the omicron-predominant period, particularly for important sub-groups that may have variable risk for severe COVID-19 outcomes. We report initial findings from the INFORM study describing the clinical burden and severe COVID-19 outcomes in patients with immunocompromised conditions (IC) in England, UK in 2022. Methods This retrospective cohort study utilized National Health Service database in England. The study period was from Jan 1–Dec 31, 2022 and the baseline period for assessment of patient characteristics, including IC, was from Jan 1, 2017–Dec 31, 2021. Definitions of IC sub-groups are provided in Table 1. Severe COVID-19 outcomes were defined as COVID-19–related hospitalization, COVID-19–related intensive care unit (ICU) admission, and/or COVID-related death. Results Of the 11,990,730 individuals in the general population sample aged ≥ 12 years, 468,745 (3.9%) were immunocompromised and accounted for approximately one-quarter of severe COVID-19–related outcomes (22% of hospitalizations, 28% of ICU admissions, and 23% of deaths; Table 2). The risk of severe COVID-19 outcomes was higher in well-recognized IC conditions (eg, solid organ transplants, hematological malignancies, and solid tumors) across all the sub-groups compared with the overall population (Table 2). Conclusion There is an increased burden in the prevalence of severe COVID-19 outcomes among all individuals with IC, highlighting the need for additional protection to target this population. Disclosures Richard McNulty, MD, AstraZeneca: Employee Sabada Dube, PhD, AstraZeneca: Employee Yi Lu, PhD, Evidera: Employee Sophie Graham, MSc, Evidera: Employee Sofie Arnetorp, MS, AstraZeneca: Employee Nahila Justo, PhD, MBA, Evidera: Employee|Karolinska Institute: Employee Renata Yokota, PhD, AstraZeneca: Employee Kathryn Evans, MPH, Evidera: Employee Sudhir Venkatesan, MPH, PhD, AstraZeneca: Employee Mark Yates, PhD, Evidera: Employee Sylvia Taylor, PhD, MPH, MBA, AstraZeneca: Stocks/Bonds Jennifer Quint, PhD, AstraZeneca: Grant/Research Support|Evidera: Grant/Research Support|GlaxoSmithKline: Grant/Research Support|Insmed: Grant/Research Support Rachael A. Evans, PhD FRCP, Astr