Nathanael R. Fillmore
Topics / Severe COVID-19
Topic

Severe COVID-19

Fillmore has investigated the determinants of severe COVID-19, with a specific focus on high-risk populations including older adults and patients with hematologic cancers or solid organ transplants. His work demonstrates that immunocompromised status and plasma cell disorders significantly increase the risk of breakthrough infections and disease progression despite vaccination. To mitigate these risks, he developed a dynamic risk prediction tool to identify candidates for antiviral therapies and has advocated for the use of severity-adjusted hospitalization metrics to accurately measure vaccine effectiveness.

U.S. Veterans and VA Data 9 COVID-19 9 Retrospective Cohort Study 6 Electronic Health Records 5 Vaccine Effectiveness 5 Logistic Regression 4 Immunosuppressive Therapy 4 Real World Evidence 3 Hematologic Malignancies 3 Vaccination 3 Risk Factors 3 Observational Study 3

Publications (9)

2025

Leveraging near-real-time patient and population data to incorporate fluctuating risk of severe COVID-19: development and prospective validation of a personalised risk prediction tool.

Kaitlin Swinnerton†, Nathanael R. Fillmore†, Austin Vo, Jennifer La, Danne Elbers, Mary Brophy, Nhan V. Do, Paul A. Monach‡, Westyn Branch-Elliman‡† Equal first authorship · ‡ Equal senior authorship

eClinicalMedicine81, 103114
U.S. Veterans and VA Data Retrospective Cohort Study COVID-19 Severe COVID-19 Predictive Modeling
2023

Coronavirus disease 2019 (COVID-19) hospitalization metrics that do not account for disease severity underestimate protection provided by severe acute respiratory coronavirus virus 2 (SARS-CoV-2) vaccination and boosting: A retrospective cohort study.

June K. Corrigan†, Jennifer La†, Nathanael R. Fillmore, Nhan V. Do, Mary Brophy, Shira Doron, Paul A. Monach‡, Westyn Branch-Elliman‡† Equal first authorship · ‡ Equal senior authorship

Infection Control and Hospital Epidemiology44(1), 149-151
U.S. Veterans and VA Data Retrospective Cohort Study Electronic Health Records COVID-19 Vaccine Effectiveness
2022

The COVID-19 hospitalization metric in the pre- and postvaccination eras as a measure of pandemic severity: A retrospective, nationwide cohort study.

Nathanael R. Fillmore†, Jennifer La†, Chunlei Zheng, Shira Doron, Nhan V. Do, Paul A. Monach‡, Westyn Branch-Elliman‡† Equal first authorship · ‡ Equal senior authorship

Infection Control and Hospital Epidemiology43(12), 1767-1772
U.S. Veterans and VA Data Retrospective Cohort Study COVID-19 Vaccine Effectiveness Hospitalization Metrics