1029. Clinical Characteristics and Outcomes of Neuroinvasive West Nile Virus Infection in Immunocompromised and Immunocompetent Individuals

Background Despite the increasing incidence of neuroinvasive West Nile virus (NiWNV) infection in the US, the spectrum of disease characteristics and neuroimaging findings in immunosuppressed (IS) individuals are not adequately described. We aimed to compare the clinical characteristics and outcomes of NiWNV infection in IS and immunocompetent (IC) patients. Methods We extracted relevant data from all NiWNV patients hospitalized 7/2003-10/2021 at Mayo Clinic hospitals. Cohort was inclusive of patients from the recent historic WNV outbreak in Arizona in 2021. Chi-Square or Kruskal-Wallis and logistic regression were used to compare relevant variables and determine predictors of mortality respectively. Results We included 115 patients (72 IC and 43 IS), mean age 63.5 years; neurologic syndromes included meningoencephalitis (85.2%), encephalomyelitis (8.7%) and myeloradiculitis (6.1%). Presenting symptoms were malaise (72%), fever (66%), altered mentation (64%), gastrointestinal (47%) and myalgia (35.7%). MRI brain was abnormal in 62.8% (49/78), demonstrating T2/FLAIR hyperintensities in 47.4% (brainstem, thalamus, temporal lobes), leptomeningeal enhancement (16.7%) and diffusion restriction (20.5%). Altered mental status (76.7% vs 56.9%), myalgia (44.4% vs. 20.9%), myoclonus (18.6% vs. 4.2%) and thalamic MRI T2 FLAIR abnormalities (11.4% vs 0%) were more common in IS patients. Higher CSF WBC counts were observed in IC vs IS patients (P< 0.05). Immunosuppressed patients were more likely to be treated with intravenous immunoglobulin (44.2% vs 8.3% p=< 0.001) and/or interferon therapy (32.6% vs 6.9%, p=0.0003) and had increased odds of 90-day mortality on multivariable analysis (Adjusted Odds Ratio, AOR 2.22; 95% CI 1.065-4.627, p=0.0334). In the IS subgroup, ICU admission, mechanical ventilation, and Glasgow coma scale of < 8 were associated with reduced overall survival/increased 90-day mortality (p< 0.005). Conclusion Individuals presenting in summer/fall months with the aforementioned symptoms and/or MRI abnormalities should be evaluated for NiWNV infection. Compared to the immunocompetent, immunosuppressed patients with NiWNV are at a significantly greater mortality risk. Novel and effective antiviral therapies aimed at improving outcomes are warranted. Disclosures All Authors: No reported disclosures.