About

Christopher B Forrest, MD, PhD, is a Professor of Pediatrics (General Pediatrics) at the Children's Hospital of Philadelphia and a Professor at the Wharton School of Business. He holds a BA in Biology from Boston University, an MD from Boston University, and a PhD in Health Policy and Management from Johns Hopkins University. His research focuses on pediatric health, with significant contributions to understanding antihypertensive medication effectiveness in children with chronic kidney disease, blood pressure control in adolescents, and the use of pediatric learning health systems to characterize treatment responses in conditions such as lupus nephritis and recurrent glomerulosclerosis. Dr. Forrest is involved in multiple multicenter studies and has contributed to advancing clinical research methodologies, including data fitness assessment in clinical research and vaccine effectiveness in children. His work emphasizes improving pediatric healthcare outcomes through rigorous research and innovative health policy approaches.

Research topics

• Computer Science
• Medicine
• Algorithm
• Engineering
• Virology
• Internal medicine
• Statistics
• Mathematics
• Electrical engineering

Selected publications

• Target Trial Emulation of Vaccine Effectiveness in 5- to 17-years-olds with Prior SARS-CoV-2 Infection

  Nature Communications · 2026-04-17

  articleOpen access

  The effectiveness of COVID-19 vaccination in children and adolescents with prior SARS-CoV-2 infection remains unclear, particularly for Omicron subvariants. We evaluate vaccine effectiveness against reinfection with Omicron BA.1/BA.2, BA.4/BA.5, XBB, and later subvariants among 5- to 17-year-olds using data from the RECOVER initiative, a national electronic health record database covering 37 U.S. children’s hospitals and health institutions. We emulate target trials by age group and variant period, comparing previously infected participants between January 2022 and August 2023. During the BA.1/BA.2 period, vaccination reduces the risk of reinfection, with effectiveness rates of 62% in children and 65% in adolescents. During the BA.4/BA.5 period, protection effectiveness in children was 57%, whereas no statistically significant protection is observed in adolescents. During the XBB and later period, no significant protection is observed in either group. In summary, COVID-19 vaccination provides protection against reinfection during the early and mid-Omicron periods in previously infected pediatric populations, but effectiveness declines for later variants. This study found COVID-19 vaccination offers added protection against reinfection in children and adolescents with prior infection but variable effectiveness across variants. Findings support vaccination benefits beyond infection-acquired immunity.

  PublisherOA PDFDOI

• Identifying Pediatric Long COVID: Comparing an EHR Algorithm to Manual Review

  Applied Clinical Informatics · 2025-10-01

  articleOpen access

  Abstract Long COVID, characterized by persistent or recurring symptoms post-COVID-19 infection, poses challenges for pediatric care and research due to the lack of a standardized clinical definition. Adult-focused phenotypes do not translate well to children, given developmental and physiological differences, and pediatric-specific phenotypes have not been compared with chart review. This study introduces and evaluates a pediatric-specific rule-based computable phenotype (CP) to identify long COVID using electronic health record data. We compare its performance to manual chart review. We applied the CP, composed of diagnostic codes empirically associated with long COVID, to 339,467 pediatric patients with SARS-CoV-2 infection in the RECOVER PCORnet EHR database. The CP identified 31,781 patients with long COVID. Clinicians conducted chart reviews on a subset of patients across 16 hospital systems to assess performance. We qualitatively reviewed discordant cases to understand differences between CP and clinician identification. Among the 651 reviewed patients (339 females, M age = 10.10 years), the CP showed moderate agreement with clinician identification (accuracy = 0.62, positive predictive value [PPV] = 0.49, negative predictive value [NPV] = 0.75, sensitivity = 0.52, specificity = 0.84). Performance was largely consistent across age and dominant variant but varied by symptom cluster count. Most discrepancies between the CP and chart review occurred when the CP identified a case, but the clinician did not, often because clinicians attributed symptoms to preexisting conditions (73%). When clinicians identified cases missed by the CP, they often used broader symptom or timing criteria (69%). Model performance improved when the CP accounted for preexisting conditions (accuracy = 0.71, PPV = 0.65, NPV = 0.74, sensitivity = 0.59, specificity = 0.79). This study presents a CP for pediatric long COVID. While agreement with manual review was moderate, most discrepancies were explained by differences in interpreting symptoms when patients had preexisting conditions. Accounting for these conditions improved accuracy and highlights the need for a consensus definition. These findings support the development of reliable, scalable tools for pediatric long COVID research.

  PublisherOA PDFDOI

• Post-acute dyslipidemia and abnormal BMI in children and adolescents with COVID-19: An EHR Cohort Study from the RECOVER Initiative

  medRxiv · 2025-09-19 · 1 citations

  preprintOpen access

  Summary Background Adults with SARS-CoV-2 infection have shown higher risks of dyslipidaemia and abnormal body mass index (BMI). Whether similar associations exist in children and adolescents is unclear. Method We did a retrospective cohort study using the RECOVER paediatric Electronic Health Record (EHR) datasets from 25 US children’s hospitals, covering March 2020 to September 2023. For dyslipidaemia analyses, we included 384,289 patients aged 0–21 years with at least 6 months of follow-up and 1,080,413 COVID-19-negative controls. For BMI analyses, we included 285,559 patients aged 2–21 years and 817,315 controls. Documented infection was defined as a positive PCR, serology, or antigen test, or a clinical diagnosis of COVID-19 or post-acute sequelae of SARS-CoV-2. Outcomes were new diagnoses of dyslipidaemia, defined by laboratory thresholds for total cholesterol, triglycerides, LDL cholesterol, HDL cholesterol, and non-HDL cholesterol, and abnormal BMI (BMI-for-age ≥95th percentile at ages 2–19 years or BMI ≥30 kg/m² at ages 19–21 years). Adjusted relative risks (aRRs) were estimated using propensity score-stratified Poisson regression. Sensitivity analyses included empirical calibration with negative control outcomes and stratification by baseline obesity. Interpretation Children and adolescents with documented COVID-19 were associated with higher risks of new-onset dyslipidaemia and abnormal BMI in the post-acute period compared with COVID-19-negative peers. Associations were consistent across lipid fractions, remained after empirical calibration, and were similar after accounting for baseline obesity. Research in context Evidence before this study Adults with SARS-CoV-2 infection have been reported to develop dyslipidaemia and abnormal body mass index (BMI) after the acute phase, raising concerns about long-term metabolic health. In children and adolescents, evidence has been scarce. Available studies are small, cross-sectional, or based mainly on diagnosis codes, with few incorporating laboratory lipid values or age-specific BMI thresholds against contemporaneous controls. The risk of post-acute dyslipidaemia and BMI abnormalities in paediatric populations therefore remains uncertain. Added value of this study Using the Researching COVID to Enhance Recovery (RECOVER) electronic health record (EHR) database from 25 US hospitals, we examined more than 1.6 million children and adolescents with at least 6 months of follow-up. Outcomes were defined using laboratory lipid panels and age-specific BMI measures. With propensity score stratification across hundreds of covariates and calibration using negative control outcomes, documented COVID-19 was associated with higher adjusted risks of abnormal HDL cholesterol, LDL cholesterol, total cholesterol, triglycerides, and BMI. Associations were consistent across sensitivity analyses and stratified by baseline obesity. Implications of all the available evidence Together with findings from adult studies, our results indicate that metabolic sequelae after SARS-CoV-2 infection are also relevant in paediatric populations. Children and adolescents with documented COVID-19 were more likely to develop dyslipidaemia and abnormal BMI in the early post-acute phase. These findings support routine lipid and BMI monitoring in paediatric follow-up care, which could enable earlier identification of metabolic dysfunction and guide preventive strategies for long-term cardiometabolic health.

  PublisherOA PDFDOI

• A multifaceted approach to advancing data quality and fitness standards in multi-institutional networks

  Journal of the American Medical Informatics Association · 2025-10-04

  articleOpen access

  OBJECTIVE: To construct a data quality (DQ) system that incorporates combinations of methods to evaluate data characteristics and analytic fitness across research questions for multiple uses. MATERIALS AND METHODS: Drawing from experience of other data quality programs, network data extraction needs, and recurring study requirements, we developed 5 standards to guide development of a modular, multifaceted data quality system. These included annotation and documentation, ability to measure research readiness, reproducibility across networks, flexibility for the user, and interpretability to research and project teams. Implementation of checks based on these principles focused on reusability and interactive visualization of results. RESULTS: We identified 10 check types producing over 444 check applications and deployed them in 2 multi-institutional networks. Check types span structural conformance to a data model, utility for common research needs, and study-specific customization. All check types are customizable without dependencies between them. A dashboard visualizes results, permitting adjustments based on number of data sources, need for source masking, and the user's focus. All components can be applied as written to any data source using OMOP and are readily modified for other data models. DISCUSSION: We have extended previous work through our novel and multifaceted approach to data quality assessment, addressing needs in both network data improvement and research usage. We developed a capable and deployable system rather than tailoring to specific use cases. CONCLUSION: Our novel DQ assessment system provides essential components for future standardization and collaboration to improve fitness of clinical data for intended use.

  PublisherOA PDFDOI

• Pediatric Gastrointestinal Tract Outcomes During the Postacute Phase of COVID-19

  JAMA Network Open · 2025-02-07 · 10 citations

  articleOpen access

  Importance: The profile of gastrointestinal (GI) tract outcomes associated with the postacute and chronic phases of COVID-19 in children and adolescents remains unclear. Objective: To investigate the risks of GI tract symptoms and disorders during the postacute (28-179 days after documented SARS-CoV-2 infection) and the chronic (180-729 days after documented SARS-CoV-2 infection) phases of COVID-19 in the pediatric population. Design, Setting, and Participants: This retrospective cohort study was performed from March 1, 2020, to September 1, 2023, at 29 US health care institutions. Participants included pediatric patients 18 years or younger with at least 6 months of follow-up. Data analysis was conducted from November 1, 2023, to February 29, 2024. Exposures: Presence or absence of documented SARS-CoV-2 infection. Documented SARS-CoV-2 infection included positive results of polymerase chain reaction analysis, serological tests, or antigen tests for SARS-CoV-2 or diagnosis codes for COVID-19 and postacute sequelae of SARS-CoV-2. Main Outcomes and Measures: GI tract symptoms and disorders were identified by diagnostic codes in the postacute and chronic phases following documented SARS-CoV-2 infection. The adjusted risk ratios (ARRs) and 95% CI were determined using a stratified Poisson regression model, with strata computed based on the propensity score. Results: The cohort consisted of 1 576 933 pediatric patients (mean [SD] age, 7.3 [5.7] years; 820 315 [52.0%] male). Of these, 413 455 patients had documented SARS-CoV-2 infection and 1 163 478 did not; 157 800 (13.6%) of those without documented SARS-CoV-2 infection had a complex chronic condition per the Pediatric Medical Complexity Algorithm. Patients with a documented SARS-CoV-2 infection had an increased risk of developing at least 1 GI tract symptom or disorder in both the postacute (8.64% vs 6.85%; ARR, 1.25; 95% CI, 1.24-1.27) and chronic (12.60% vs 9.47%; ARR, 1.28; 95% CI, 1.26-1.30) phases compared with patients without a documented infection. Specifically, the risk of abdominal pain was higher in COVID-19-positive patients during the postacute (2.54% vs 2.06%; ARR, 1.14; 95% CI, 1.11-1.17) and chronic (4.57% vs 3.40%; ARR, 1.24; 95% CI, 1.22-1.27) phases. Conclusions and Relevance: In this cohort study, the increased risk of GI tract symptoms and disorders was associated with the documented SARS-CoV-2 infection in children or adolescents during the postacute or chronic phase. Clinicians should note that lingering GI tract symptoms may be more common in children after documented SARS-CoV-2 infection than in those without documented infection.

  PublisherDOI

• Trends in US Children’s Mortality, Chronic Conditions, Obesity, Functional Status, and Symptoms

  JAMA · 2025-07-07 · 43 citations

  articleOpen access1st authorCorresponding

  Importance: Recent scientific and policy statements suggest that child health may be worsening in the US. Objective: To determine how US children's health has been changing from 2007 to 2023 using multiple data collection methods and a comprehensive set of health indicators. Design, Setting, and Participants: Repeated, cross-sectional analyses using mortality statistics from the US and 18 comparator high-income nations from the Organisation for Economic Co-operation and Development (OECD18), 5 nationally representative surveys, and electronic health records from 10 pediatric health systems (PEDSnet). The populations included individuals younger than 20 years old. Unweighted denominator sample size ranges were 1623 to 95 677 across the surveys, 1 026 926 to 2 114 638 for PEDSnet, 81.9 million to 83.2 million in the US, and 118.4 million to 121.1 million in the OECD18 for mortality statistics. Exposure: Calendar time. Main Outcomes and Measures: Rate ratios (RRs) and annual incidence for mortality and prevalence for chronic physical, developmental, and mental health conditions, functional status, and symptoms. Results: From 2007 to 2022, infants (<1 year old) were 1.78 (95% CI, 1.78-1.79) and 1- to 19-year-old individuals were 1.80 (95% CI, 1.80-1.80) times more likely to die in the US than in the OECD18. The 2 causes of death with the largest net difference between the US and OECD18 were prematurity (RR, 2.22 [95% CI, 2.20-2.24]) and sudden unexpected infant death (RR, 2.39 [95% CI, 2.35-2.43]) for infants 12 months or younger, and firearm-related incidents (RR, 15.34 [95% CI, 14.89-15.80]) and motor vehicle crashes (RR, 2.45 [95% CI, 2.42-2.48]) for 1- to 19-year-old individuals. From 2011 to 2023, the prevalence of 3- to 17-year-old individuals with a chronic condition rose from 39.9% to 45.7% (RR, 1.15 [95% CI, 1.14-1.15]) within PEDSnet, and from 25.8% to 31.0% (RR, 1.20 [95% CI, 1.20-1.20]) within the general population. Rates of obesity, early onset of menstruation, trouble sleeping, limitations in activity, physical symptoms, depressive symptoms, and loneliness all increased during the study period. Conclusions and Relevance: The health of US children has worsened across a wide range of health indicator domains over the past 17 years. The broad scope of this deterioration highlights the need to identify and address the root causes of this fundamental decline in the nation's health.

  PublisherOA PDFDOI

• Percutaneous Nephrolithotomy vs Ureteroscopy for Kidney Stones in Children

  JAMA Network Open · 2025-06-20 · 7 citations

  articleOpen access

  Importance: Based on expert opinion, clinical guidelines recommend percutaneous nephrolithotomy or shockwave lithotripsy for children and adolescents with kidney stones 20 mm or larger, without mention of ureteroscopy as an alternative. Objective: To compare clinical and patient-reported outcomes for percutaneous nephrolithotomy vs ureteroscopy in children and adolescents with kidney and/or ureteral stones. Design, Setting, and Participants: This prospective cohort study was performed at 31 medical centers in the US and Canada. Participants included patients aged 8 to 21 years undergoing surgery for kidney and/or ureteral stones between March 16, 2020, and July 31, 2023. Exposures: Percutaneous nephrolithotomy vs ureteroscopy. Main Outcomes and Measures: Stone clearance assessed by ultrasonography 6 (±2) weeks postoperatively. Secondary outcomes included patient-reported outcomes 1 week after surgery. Results: The study enrolled 1039 eligible patients (median age, 15.6 [IQR, 12.5-17.3] years; 629 female [60.5%]; 40 Black [3.8%]; 128 Hispanic [12.3%]; and 792 White [76.2%]). One hundred twenty-six urologists performed percutaneous nephrolithotomy for 98 kidneys and/or ureters and ureteroscopy for 1069, including 36 undergoing percutaneous nephrolithotomy and 43 undergoing ureteroscopy for stones larger than 15 mm. Stone clearance was 67.2% (95% CI, 46.0%-88.4%) for percutaneous nephrolithotomy and 73.4% (95% CI, 69.4%-77.4%) for ureteroscopy, a difference that was not statistically significant (risk difference, -6.2%; 95% CI, -27.7% to 15.4%). For stones larger than 15 mm, stone clearance was 94.0% (95% CI, 83.3%-100%) for percutaneous nephrolithotomy and 55.0% (95% CI, 32.9%-77.1%) for ureteroscopy, a statistically significant difference (risk difference, 39.0%; 95% CI, 14.4%-63.5%). Compared with ureteroscopy, percutaneous nephrolithotomy had significantly lower pain intensity (T score difference, -5.42; 95% CI, -10.38 to -0.46), pain interference (T score difference, -5.88; 95% CI, -11.02 to -0.75), anxiety (T score difference, -5.74; 95% CI, -9.26 to -2.22), psychological stress experiences (T score difference, -7.90; 95% CI, -13.13 to -2.67), sleep disturbance (T score difference, -5.57; 95% CI, -8.56 to -2.58), and urinary symptoms (symptom score difference, -6.37; 95% CI, -11.71 to -1.03) 1 week after surgery. Conclusions and Relevance: Compared with ureteroscopy, percutaneous nephrolithotomy had similar stone clearance and better lived experiences for children and adolescents and was associated with greater stone clearance of kidney stones larger than 15 mm. A future adequately powered prospective clinical trial is needed to reaffirm these results.

  PublisherOA PDFDOI

• Cardiovascular post-acute sequelae of SARS-CoV-2 in children and adolescents: cohort study using electronic health records

  Nature Communications · 2025-04-11 · 18 citations

  articleOpen access

  The risk of cardiovascular outcomes following SARS-CoV-2 infection has been reported in adults, but evidence in children and adolescents is limited. This paper assessed the risk of a multitude of cardiac signs, symptoms, and conditions 28-179 days after infection, with outcomes stratified by the presence of congenital heart defects (CHDs), using electronic health records (EHR) data from 19 children's hospitals and health institutions from the United States within the RECOVER consortium between March 2020 and September 2023. The cohort included 297,920 SARS-CoV-2-positive individuals and 915,402 SARS-CoV-2-negative controls. Every individual had at least a six-month follow-up after cohort entry. Here we show that children and adolescents with prior SARS-CoV-2 infection are at a statistically significant increased risk of various cardiovascular outcomes, including hypertension, ventricular arrhythmias, myocarditis, heart failure, cardiomyopathy, cardiac arrest, thromboembolism, chest pain, and palpitations, compared to uninfected controls. These findings were consistent among patients with and without CHDs. Awareness of the heightened risk of cardiovascular disorders after SARS-CoV-2 infection can lead to timely referrals, diagnostic evaluations, and management to mitigate long-term cardiovascular complications in children and adolescents.

  PublisherDOI

• Is local air pollution concentration a moderator or mediator of the association between residential greenspace and pediatric asthma exacerbations? A longitudinal study of pediatric patients in Philadelphia, Pennsylvania

  International Journal of Hygiene and Environmental Health · 2025-03-06 · 2 citations

  article
  PublisherDOI

• Utilization of anti-CD20 antibodies for treatment of childhood nephrotic syndrome, 2010 to 2022

  Pediatric Nephrology · 2025-06-05 · 2 citations

  articleOpen accessSenior author
  PublisherOA PDFDOI

Recent grants

• NIH Grant U01AR05795602

  NIH · $1.0M · 2013

• NIH Grant K02HS000003

  NIH · $365k · 2004

• NIH Grant R13HS016070

  NIH · $27k · 2005

• NIH Grant F32HS000070

  NIH · $31k

• NIH Grant U01AR057956

  NIH · $3.8M · 2015

Frequent coauthors

• Dimitri Christakis

  University of Washington

  531 shared

• Jason P. Block

  Harvard Pilgrim Health Care

  526 shared

• Deepika Thacker

  Nemours Children's Health System

  509 shared

• Katherine B. Bevans

  508 shared

• Grace M. Lee

  Texas Children's Hospital

  502 shared

• Michael D. Kappelman

  498 shared

• Jon Puro

  Ochin

  492 shared

• Lindsay G. Cowell

  491 shared

Education

• PhD, Health Policy and Management

  Johns Hopkins University

  1995

• M.D., Medicine

  Boston University

  1986

• B.A., Biology

  Boston University

  1982