1096. Fully Vaccinated Individuals with Immunocompromised Conditions (IC) are Still at Increased Risk of Severe COVID-19 Outcomes From the Omicron Variant: Initial Results From INFORM, a Retrospective Health Database Observational Study in England

BACKGROUND: UK vaccination programs have reduced COVID-19–related hospitalizations and deaths in the overall population, yet vaccinated individuals with immunocompromised conditions (IC) are still at high risk of severe COVID-19 outcomes. Contemporary evidence on severe outcomes in vaccinated individuals with IC is needed, particularly in the post-pandemic omicron period. Initial results from INFORM, an observational retrospective cohort study describing COVID-19 health burden in individuals with and without IC vaccinated with ≥ 3 doses of a COVID-19 vaccine in England, are presented. METHODS: Data from primary and secondary care linked to COVID-19 surveillance, vaccination records, primary care dispensations, and mortality, were accessed via National Health Service (NHS) database (Figure 1). The study period was Jan 1, 2022–Dec 31, 2022. Baseline characteristics were identified during the period Jan 1, 2017–Dec 31, 2021. Incidence rates (IR) are presented per 100 person-years (PY). [Figure: see text] RESULTS: Almost 90% of individuals with IC received ≥ 3 vaccine doses compared with 60% in the overall population aged ≥ 12 years (Table 1). Among individuals receiving ≥ 3 vaccine doses, COVID-19 hospitalization IRs were 0.92 (95% confidence interval [CI]: 0.89–0.95) in individuals with IC, compared with 0.22 (95% CI: 0.21–0.23) per 100 PY in the overall population. When analyzed by IC type, IRs were higher than the total vaccinated population across all IC subgroups (RR = 2.5–21) (Table 2). COVID-19 hospitalization IRs in patients with hematological malignancies currently under treatment were 4.65 (95% CI: 4.42–4.88) and those with organ transplants were 2.95 per 100 PY (95% CI: 2.7–3.2) (Table 2). Mortality IRs per 100 PY were also consistently higher across all IC groups. [Figure: see text] [Figure: see text] CONCLUSION: Within a population vaccinated with ≥ 3 doses, individuals with IC had a higher risk of COVID-19 hospitalization and COVID-19 death compared with the overall population. This risk of severe COVID-19 outcomes was elevated across all IC groups, regardless of past or current treatment or procedure despite being vaccinated. DISCLOSURES: Sabada Dube, PhD, AstraZeneca: Employee Yi Lu, PhD, Evidera: Employee Richard McNulty, MD, AstraZeneca: 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, AstraZeneca: Advisor/Consultant|Boehringer: Advisor/Consultant|Evidera: Advisor/Consultant