About

Brian T. Fisher, DO, MSCE, MPH, is a Professor of Pediatrics (Infectious Diseases) at the Children's Hospital of Philadelphia. He is also a Senior Scholar at the Center for Clinical Epidemiology and Biostatistics at the University of Pennsylvania and serves as the Director of Infectious Diseases and Oncology Clinical Care at the Children's Hospital of Philadelphia. His research focuses on infectious diseases, epidemiology, and biostatistics, contributing to clinical epidemiology and pediatric infectious disease care.

Research topics

• Medicine
• Internal medicine
• Intensive care medicine
• Pathology
• Surgery
• Immunology
• Environmental health
• Dermatology
• Clinical psychology
• Psychology
• Psychiatry
• Oncology
• Social psychology
• Developmental psychology
• Virology

Selected publications

• High Rates of Clinically Significant Late Infections and Recurrent Sinopulmonary Disease in Long-Term Survivors after CD19 CAR T-cell Therapy for Pediatric B-ALL

  Transplantation and Cellular Therapy · 2026-02-01

  article
  PublisherDOI

• P-1122. Community Transmission and Hospital-Acquired Infections During Outbreaks: Temporal Patterns and Predictive Modeling

  Open Forum Infectious Diseases · 2026-01-01

  articleOpen access

  Abstract Background Hospital-acquired infections (HAIs) threaten patient safety and strain healthcare systems, with heightened risks during outbreaks like COVID-19. While hospital-based prevention is well-studied, the role of community transmission in driving HAIs caused by outbreak pathogens remains underexamined. Understanding this relationship, which may also vary by region and hospital, is critical for preparedness and targeted responses. Methods We conducted a retrospective study of 1,814 U.S. acute care hospitals using data of daily COVID-19 HAIs, county-level COVID-19 case counts, ED visits, county and hospital-level characteristics from October 2020 to March 2022. Temporal relationships between community transmission and COVID-19 HAIs were assessed using autocorrelation and cross-correlation analyses. Predictive models were developed using zero-inflated negative binomial (ZINB) regression for daily COVID-19 HAI to address excess zeros and overdispersion. A generalized linear mixed model was developed for high vs. low HAI-to-bed ratios. Model performance was evaluated via time-based validation across key pandemic phases, using rolling train-test splits, and hospital-based validation by repeatedly training on 80% of hospitals and testing on the remaining 20% to assess generalizability across sites. Results Community case counts lagged by 9-10 days and ED visits lagged by 13-16 days were strongly associated with HAIs. The ZINB model moderately predicted daily HAI counts, with underperformance during epidemic surges. Meanwhile, the binary classification model for high/low HAI-to-bed ratios achieved strong accuracy (74-91%) and AUCs of 0.81-0.97 across different pandemic phases. Hospital characteristics did not significantly improve model performance. Conclusion Community transmission is a leading indicator of HAIs during COVID. Predictive models incorporating lagged community data can support early detection of high-risk periods. Binary risk classification may be more actionable and robust than count-based forecasts, especially during periods of rapid change. These findings support integrating community surveillance into hospital infection prevention and control planning to enhance pandemic preparedness. Disclosures Brian T. Fisher, DO, MPH/MSCE, Merck: Grant/Research Support|Pfizer: Grant/Research Support

  PublisherDOI

• 633. Incidence and Outcomes of Pediatric Allogeneic Hematopoietic Cell Transplant (allo-HCT) Recipients Under Surveillance and Not Under Surveillance for Human Adenovirus (HAdV) in the Post-HCT Period

  Open Forum Infectious Diseases · 2025-01-29

  articleOpen accessSenior author

  Abstract Background Human Adenovirus (HAdV) can cause life-threatening illness in pediatric allo-HCT recipients, but studies to define incidence and outcomes of HAdV in allo-HCT patients are limited. Use of PCR-based HAdV surveillance varies by HCT center, in part because there are no approved HAdV-directed therapies. This study describes the epidemiology of HAdV infection and disease in pediatric allo-HCT patients who did and did not undergo HAdV surveillance. Methods An allo-HCT cohort was assembled from July 2018 to June 2021 at ten US pediatric HCT centers. Patients were followed for 180 days from HCT to document presence of HAdV infection and disease and were considered under surveillance if ≥ 2 HAdV blood tests were run in the first 14 days post-HCT. Published HAdV disease and attributable death definitions were applied to patients with positive HAdV PCR tests from any site and adjudicated by a central review committee. HAdV events were designated asymptomatic infection or possible, probable, or proven disease. HAdV DNAemia and disease incidence, time to event, and mortality and attributable case fatality rates were described. Results The cohort included 831 allo-HCT recipients: 645 under surveillance & 186 not (Table 1). 15.5% of patients under surveillance had DNAemia; median time to DNAemia was 31.0 days from HCT (Table 2). Probable/proven disease was documented in 11.9% and 3.8% of patients under and not under surveillance, with median time to disease 37.0 days and 66.0 days from HCT, respectively (Table 3). Overall mortality rates were 7.6% and 8.6% in patients under and not under surveillance (Table 4). Attributable case fatality rates for those with probable or proven disease were 13.0% and 14.3% in those under and not under surveillance, respectively. Conclusion HAdV infection and disease events were frequent; however, incidence was higher in patients under surveillance, suggesting detection bias. HAdV disease was identified as a frequent cause of death. Attributable case fatality rates were similar regardless of surveillance, suggesting early detection did not improve outcomes. Future analyses of these data will determine patient factors that identify allo-HCT patients at high risk for HAdV infection and disease to target for novel prophylaxis or pre-emptive therapy studies. Disclosures Michael D. Green, MD, MPH, ADMA: Advisor/Consultant|Bristol Myers Squibb: Advisor/Consultant|ITB-MED: Advisor/Consultant|kamada: Honoraria Monica I. Ardura, DO, MSCS, Karius: Advisor/Consultant|Miravista: Grant/Research Support Jeffrey Auletta, MD, Ascella Health: Advisor/Consultant Diego R. Hijano, MD, MSc, FDA: Grant/Research Support|Merck: Grant/Research Support|National Institute of Health: Grant/Research Support William J. Muller, MD, Ansun Biopharma: Grant/Research Support|Astellas Pharma: Advisor/Consultant|Astellas Pharma: Grant/Research Support|AstraZeneca: Advisor/Consultant|AstraZeneca: Grant/Research Support|DiaSorin: Advisor/Consultant|DiaSorin: Honoraria|Eli Lilly and Company: Grant/Research Support|Enanta Pharmaceuticals: Advisor/Consultant|Enanta Pharmaceuticals: Grant/Research Support|F. Hoffmann-LaRoche Ltd (Roche): Grant/Research Support|Finley Law Firm, P.C.: Advisor/Consultant|Gilead Sciences: Grant/Research Support|Melinta Therapeutics, Inc.: Grant/Research Support|Merck Sharpe & Dohme: Grant/Research Support|Moderna: Grant/Research Support|Nabriva Therapeutics, plc: Grant/Research Support|Paratek Pharmaceuticals, Inc.: Grant/Research Support|Pfizer: Grant/Research Support|ProventionBio: Advisor/Consultant|Sanofi: Advisor/Consultant|Sanofi: Honoraria|Tetraphase Pharmaceuticals, Inc.: Grant/Research Support Michael Grimley, MD, SymBio Pharmaceuticals Limited: Advisor/Consultant Lara A. Danziger-Isakov, MD, MPH, Aicuris: clinical research contract, paid to institutio|Ansun BioPharma: clinical research contract, paid to institution|Astellas: Advisor/Consultant|Astellas: clinical research contract, paid to institutio|Merck: clinical research contract, paid to institutio|Pfizer: Grant/Research Support|Takeda: clinical research contract, paid to institutio Brian T. Fisher, DO, MPH/MSCE, Allovir: Grant/Research Support|Astellas: Data Safety Monitoring Board|Merck: Grant/Research Support|Pfizer: Grant/Research Support

  PublisherOA PDFDOI

• P-637. Infection Incidence and Trajectory of Immune Recovery in Children, Adolescents, and Young Adults After Chemotherapy for Acute Lymphoblastic Leukemia

  Open Forum Infectious Diseases · 2025-01-29 · 1 citations

  articleOpen accessSenior author

  Abstract Background Advances in chemotherapy for acute lymphoblastic leukemia (ALL) have improved survival rates, but survivors remain vulnerable to infection after completing chemotherapy. Data have shown increased infection risk for pediatric ALL survivors compared to healthy children, yet few studies have prospectively tracked infection rates alongside immune recovery. This study aims to quantify infection incidence and describe the trajectory of immune reconstitution in the year after ALL therapy completion. Methods Patients aged 3-30 completing ALL therapy at a pediatric center are being followed for the first year off-therapy. Total immunoglobulin-G (IgG) and antibody (Ab)-specific IgG levels for varicella, measles, and 23 pneumococcal serotypes are measured at 3, 6, and 12 months. Infection events are recorded monthly to calculate infection incidence per 1000 patient-days. Results To date, 21 patients have been followed for ≥ 6 months. Median age at ALL diagnosis was 7.3 years (IQR: 3.4-10.1). 67% of patients had ≥ 1 infections; 93% of those with infections had ≥ 2. The overall infection incidence rate was 6.1 per 1000 patient-days. Of 46 infections, upper respiratory illness (20, 43.5%) and gastroenteritis (6, 13%) were most common (Table 1). 17 of 21 patients had not received intravenous immunoglobulin replacement (IVIG) within 6 months of therapy completion; their mean total IgG was 859.6 mg/dL at 3 months and 918.2 mg/dL at 6 months (Table 2). All 17 received ≥ 1 pneumococcus, varicella, and/or measles vaccine before ALL diagnosis. None had evidence of pneumococcus or varicella Ab recovery at 6 months, regardless of pre-ALL partial or full vaccination status (Tables 2-3). 7/11 patients fully vaccinated and 3/6 partially vaccinated for measles before diagnosis had normal Ab indices at 6 months off-therapy (Table 4). Conclusion Infections were common during the first year off-therapy, with many experiencing multiple illnesses. Total IgG levels were reasonable at 3 and 6 months, but there was no recovery of varicella or pneumococcus Ab, and only a subset of patients retained measles Ab. Continued assessment until 12-month follow-up for all 85 enrolled patients is necessary but preliminary data suggest potential need for Ab-informed revaccination. Disclosures Brian T. Fisher, DO, MPH/MSCE, Allovir: Grant/Research Support|Astellas: Data Safety Monitoring Board|Merck: Grant/Research Support|Pfizer: Grant/Research Support

  PublisherOA PDFDOI

• Prevention and Management of Infectious Complications in Pediatric Patients With Cancer: A Survey Assessment of Current Practices Across Children's Oncology Group Institutions

  Pediatric Blood & Cancer · 2025-01-08 · 7 citations

  articleOpen access

  INTRODUCTION: While clinical practice guidelines (CPGs) for pediatric oncology infection prophylaxis and management exist, few data describe actual management occurring at pediatric oncology centers. METHODS: An electronic survey querying infection management practices in nontransplant pediatric oncology patients was iteratively created by the Children's Oncology Group (COG) Cancer Control and Supportive Care Infectious Diseases Subcommittee and sent to leaders at all COG institutions, limiting each site to one response to represent their institution. RESULTS: The response rate was 57% (129/227 institutions). Many sites reported utilizing COG-endorsed CPGs for antibacterial (76%) and antifungal prophylaxis (74%), and fever and neutropenia (FN, 64%). Most institutions reported using antimicrobial prophylaxis for patients with acute myeloid leukemia (88% antibacterial, 100% antifungal) and relapsed acute lymphoblastic leukemia (82% antibacterial, 95% antifungal). Definitions of fever, phagocyte recovery, and antibiotic duration in febrile patients varied. Most institutions administer empiric broad-spectrum antibiotics for nonneutropenic fever, although 14% reported withholding antibiotics based on initial clinical status or risk stratification tools. Most respondents reported (70%) admitting FN patients for at least 48 h, however 15% have low-risk FN protocols allowing outpatient management. FN patients remain admitted on antibiotics through count recovery in 50% of institutions, whereas the others employed various early discharge/early antibiotic discontinuation strategies. CONCLUSIONS: There is often consistency but also substantial variability in reported antimicrobial prophylaxis strategies and management of patients with fever and represents an opportunity for implementation studies to standardize application of CPG recommendations and randomized trials to advance evidence where knowledge gaps exist.

  PublisherOA PDFDOI

• School masking and COVID-19 community transmission: a synthetic control study

  Health Affairs Scholar · 2025-12-01

  articleOpen access

  Introduction: K-12 schools are not only educational settings but also hubs of social interaction, making them potential drivers of disease transmission within households and communities. While many existing studies have assessed school masking in relation to in-school transmission, the broader community impact of mandatory school masking policies on SARS-CoV-2 infection rates remains poorly understood. Methods: We conducted a retrospective quasi-experimental study using the synthetic control method to evaluate the association between masking policies and community infection rates during the fall 2021 US school reopening period, when most schools returned to in-person learning but masking policies varied substantially. Analyses accounted for community characteristics prior to reopening and baseline infection rates. Results: Counties with mandatory school masking experienced significantly lower SARS-CoV-2 infection rates than those without mandates. In the first 9 weeks after reopening, mandatory masking was associated with 820 fewer cases per 100 000 people (95% CI: 444-1185), corresponding to a relative cumulative reduction of 9.4% (95% CI: 7.3%-11.8%). The strength of this association varied by baseline infection rates, population density, and mobility patterns. Conclusion: Mandatory school masking policies were linked to meaningful reductions in community SARS-CoV-2 transmission and underscore their value as a public health intervention during pandemic surges.

  PublisherOA PDFDOI

• School masking and COVID-19 community transmission: a synthetic control study

  medRxiv · 2025-08-13

  preprintOpen access

  Background: K-12 schools play a crucial role not only as educational settings but also as hubs for social interaction among children, making them potential drivers of disease transmission within families and the broader community. Little is known about the impact of mandatory school masking policies on community SARS-CoV-2 infection rates during the COVID-19 pandemic. This study addressed this gap by evaluating the association between mandatory school masking policies and community infection rates, accounting for temporal and regional variations. Methods: We conducted a retrospective quasi-experimental study using the synthetic control method. The study focused on the fall 2021 school reopening period in the United States, a time when most U.S. schools returned to fully in-person learning but accompanied by substantial variation in masking policies. Analyses controlled community characteristics prior to reopening and baseline infection rates. Findings: Counties with mandatory school masking policies experienced lower SARS-CoV-2 infection rates compared to counties with non-mandatory policies. During the first nine weeks after school reopening, there was a reduction of 1,096 cases per 100,000 people (95% confidence interval: 880 to 1,310 fewer cases per 100,000 people). This association was influenced by baseline infection rates, population density, and mobility patterns. Interpretation: Mandatory school masking policies were associated with notable reductions in community SARS-CoV-2 infection rates during the fall 2021 school reopening period. This study highlights the potential role of school masking as a public health intervention in mitigating community transmission. Funding: Centers for Disease Control and Prevention and the National Institutes of Health.

  PublisherOA PDFDOI

• The Febrile Neutropenic Patient

  Elsevier eBooks · 2025-01-01

  book-chapter1st authorCorresponding
  PublisherDOI

• Candidiasis

  Elsevier eBooks · 2025-01-01

  book-chapter
  PublisherDOI

• AML Care at Home: An Evidence-Based Toolkit to Personalize the Care Setting for Recovery From Pediatric AML Chemotherapy

  JCO Oncology Practice · 2025-09-19

  article

  PURPOSE: Current care guidelines for children with AML recommend hospitalization during severe neutropenia. However, selected patients discharged before neutrophil recovery have similar chemotherapy course-specific bacteremia and mortality rates to those who remain hospitalized. On the basis of published literature, we developed a toolkit to guide outpatient care after myelosuppressive AML chemotherapy and piloted its implementation at a single institution. We present the pilot clinical and implementation outcomes. METHODS: The AML Care at Home toolkit includes a discharge eligibility assessment tool and outpatient management guidelines for pediatric patients with AML and was implemented on November 15, 2022. Toolkit reach, defined as the proportion of postinduction 1 courses with toolkit use (target: 60%), was the coprimary implementation outcome, and total inpatient days per course was the coprimary clinical outcome. Chart abstractions were used to ascertain total inpatient days per course and other clinical outcome designations. RESULTS: During this pilot implementation program, 22 patients underwent 48 postinduction 1 chemotherapy courses. The toolkit was used in 33 (68.8%) courses. Appropriate toolkit use allowed for early discharge in 21 (43.8%) courses and directed inpatient recovery in 11 (22.9%). Median total inpatient days were markedly fewer for toolkit-guided early-discharge courses (8 days, IQR, 5.5-14.5) than toolkit-guided inpatient-only courses (26 days, IQR, 22-39) or when the toolkit was not used as intended (31 days, IQR, 25.3-34.8). CONCLUSION: Pilot implementation of the AML Care at Home toolkit exceeded our target reach goal and led to fewer inpatient days per course than expected on the basis of previous studies of outpatient neutropenia management. These data reflect the utility of a toolkit created on the basis of published data to identify and support appropriate patients for early hospital discharge and safe outpatient monitoring.

  PublisherDOI

Recent grants

• Fungal biomarkers for diagnosis and response to therapy for pediatric candidemia

  NIH · $692k · 2014–2019

Frequent coauthors

• Richard Aplenc

  Hospital for Sick Children

  360 shared

• Lillian Sung

  Hospital for Sick Children

  293 shared

• Yimei Li

  Children's Hospital of Philadelphia

  249 shared

• Alix E. Seif

  Children's Hospital of Philadelphia

  248 shared

• L. Lee Dupuis

  University of Toronto

  230 shared

• Elio Castagnola

  Istituto Giannina Gaslini

  223 shared

• Bob Phillips

  Hull York Medical School

  222 shared

• Thomas Lehrnbecher

  Goethe University Frankfurt

  211 shared

Labs

• Fisher LabPI

Education

• Master of Science in Clinical Epidemiology, Biostatistics, Epidemiology and Informatics

  University of Pennsylvania

  2009

• DO, Chicago College of Osteopathic Medicine

  Midwestern University

  2002

• Master of Public Health, Epidemiology

  University of Illinois at Chicago

  1998

• Bachelor of Science, Biology

  University of Notre Dame

  1995