- Pediatric Infectious Diseases
- Transplant Infectious Diseases
- Infectious diseases in the immunocompromised host
Clinical Associate Professor, Pediatrics - Infectious Diseases
Director, Pediatric Infectious Diseases Fellowship Program (2017 - Present)
Boards, Advisory Committees, Professional Organizations
Associate Director, Pediatric Infectious Diseases Program for the Immunocompromised Host (PIDPIC) (2019 - Present)
Board Certification: American Board of Pediatrics, Pediatric Infectious Diseases (2022)
Fellowship: Columbia University Medical Center (2014) NY
Medical Education: University of Illinois at Chicago College of Medicine (2007) IL
Pediatric Solid Organ Transplant Recipients Demonstrate Robust Cell-Mediated and Humoral Responses to 3 Doses of mRNA SARS-CoV-2 Vaccine.
American journal of transplantation : official journal of the American Society of Transplantation and the American Society of Transplant Surgeons
Pediatric solid organ transplant recipients (pSOTR) often demonstrate suboptimal vaccine responses and are not included in Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) vaccine efficacy trials. This population has shown variable humoral immunity following SARS-CoV-2 vaccination, and no studies have assessed cell-mediated responses after SARS-CoV-2 vaccination in pSOTR. SARS-CoV2-specific interferon-gamma release assay (IGRA), immunoglobulin G (IgG), and receptor-binding domain (RBD)-ACE2 blocking antibody (Ab), were measured in pSOTR aged 5-17years after 2-3 doses of SARS-CoV-2 mRNA vaccine. Thirty-three subjects were included, with 25 tested after the 2nd dose of mRNA vaccine (V2) and 21 tested after the 3rd dose of mRNA vaccine (V3). Of the 19 subjects who had IgG testing after V3, 100.0% (19/19) had a positive IgG response. Of the 17 subjects who had IGRA testing after V3, 94.1% (16/17) had a positive IGRA response. RBD-ACE2 blocking antibody increased significantly from V2 to V3 (p=0.007). Subjects <1 year from transplant demonstrated a significantly larger increase in RBD-ACE2 blocking Ab from V2 to V3 than did those >1 year from transplant (p=0.05). SARS-CoV-2 vaccination induces humoral and cell-mediated responses in the majority of pSOTR, with improved quantitative humoral response after 3 doses.
View details for DOI 10.1111/ajt.17195
View details for PubMedID 36083190
Cellular and humoral immune response to SARS-CoV-2 vaccination and booster dose in immunosuppressed patients: An observational cohort study.
Journal of clinical virology : the official publication of the Pan American Society for Clinical Virology
2022; 153: 105217
BACKGROUND: Humoral and cellular immune responses to SARS-CoV-2 vaccination among immunosuppressed patients remain poorly defined, as well as variables associated with poor response.METHODS: We performed a retrospective observational cohort study at a large Northern California healthcare system of infection-naive individuals fully vaccinated against SARS-CoV-2 (mRNA-1273, BNT162b2, or Ad26.COV2.S) with clinical SARS-CoV-2 interferon gamma release assay (IGRA) ordered between January through November 2021. Humoral and cellular immune responses were measured by anti-SARS-CoV-2 S1 IgG ELISA (anti-S1 IgG) and IGRA, respectively, following primary and/or booster vaccination.RESULTS: 496 immunosuppressed patients (54% female; median age 50 years) were included. 62% (261/419) of patients had positive anti-S1 IgG and 71% (277/389) had positive IGRA after primary vaccination, with 20% of patients having a positive IGRA only. Following booster, 69% (81/118) had positive anti-S1 IgG and 73% (91/124) had positive IGRA. Factors associated with low humoral response rates after primary vaccination included anti-CD20 monoclonal antibodies (P<0.001), sphingosine 1-phsophate (S1P) receptor modulators (P<0.001), mycophenolate (P=0.002), and B cell lymphoma (P=0.004); those associated with low cellular response rates included S1P receptor modulators (P<0.001) and mycophenolate (P<0.001). Of patients who had poor humoral response to primary vaccination, 35% (18/52) developed a significantly higher response after the booster. Only 5% (2/42) of patients developed a significantly higher cellular response to the booster dose compared to primary vaccination.CONCLUSIONS: Humoral and cellular response rates to primary and booster SARS-CoV-2 vaccination differ among immunosuppressed patient groups. Clinical testing of cellular immunity is important in monitoring vaccine response in vulnerable populations.
View details for DOI 10.1016/j.jcv.2022.105217
View details for PubMedID 35714462
Immunizing pediatric liver transplant recipients against varicella virus using live-attenuated vaccination
View details for Web of Science ID 000783167500005
Live Virus Vaccination of Pediatric Solid-Organ Transplant Candidates Within One Month Prior to Transplantation: A Multi-Center Experience.
Transplant infectious disease : an official journal of the Transplantation Society
BACKGROUND: Solid organ transplant (SOT) recipients are at increased risk of vaccine preventable illness due to the high degree of immunosuppression required following transplantation. The current recommendation is to vaccinate with live attenuated vaccines, including Measles, Mumps and Rubella (MMR) and Varicella (VAR) vaccines, at least 4 weeks prior to transplant. However, data to support the time interval between vaccine and transplant is limited.METHODS: We conduct a literature review of the natural history of the viruses and length of viremia following live-attenuated viral vaccines and we describe a series of five cases from two pediatric transplant centers in which live attenuated viral vaccines were administered within 21 days prior to SOT.RESULTS: None of the 5 children who received MMR or VAR 8 to 21 days prior to liver (2) and heart (3) transplant suffered from vaccine related viral illness after transplant, even in the presence of significant immunosuppression with T-cell-depleting agents.CONCLUSION: These cases support that shorter intervals of live vaccine administration prior to transplant may be safe, allowing the vaccination of a larger cohort of SOT candidates. Increasing pre-transplant vaccinations is crucial since, in most cases, live viral vaccines are contraindicated post-transplantation, and the most effective vaccine approaches utilize prime-boost strategies, priming before and boosting after transplant.
View details for DOI 10.1111/tid.13667
View details for PubMedID 34145665
Culture-Independent Analysis of Pediatric Bronchoalveolar Lavage Specimens
ANNALS OF THE AMERICAN THORACIC SOCIETY
2018; 15 (9): 1047–56
The clinical utility of culture-independent testing of pediatric BAL specimens is unknown. In addition, the variability of the pediatric pulmonary microbiome with patient characteristics is not well understood.To compare testing with 16S rRNA gene-based sequencing to conventional cultures of BAL specimens in children Methods: Study subjects were not more than 22 years old and underwent BAL from May 2013 to August 2015 as part of clinical care. DNA extracted from BAL specimens was used for 16S rRNA gene-based analysis, and results were compared with routine cultures from the same samples. Indices of microbial diversity and relative taxon abundances were compared on the basis of subject characteristics (diagnosis and antibiotic use).From 81 participants (male, 51%; median age, 9 yr), 89 samples were collected. The 16S rRNA genes of 77 samples (86.5%) from 70 subjects were successfully analyzed. These 70 subjects included 23 with cystic fibrosis, 19 who were immunocompromised, and 28 who were nonimmunocompromised. Of 68 organisms identified in culture, 16S rRNA gene-based analyses detected corresponding taxa in 66 (97.1%) and also identified potentially clinically significant organisms missed by cultures (e.g., Staphylococcus, Legionella, and Pseudomonas). Taxa that varied significantly with diagnosis and antibiotic use included Veillonella, Corynebacterium, Haemophilus, and Streptococcus. The microbiota of cystic fibrosis samples was less diverse. A "core" group of 15 taxa present in all three diagnosis groups was identified.Culture-independent analysis was concordant with routine cultures and showed the potential to detect noncultured pathogens. Although culture-independent testing identified relative changes in organism abundance associated with clinical characteristics, distinct microbiome profiles associated with disease states were not identified.
View details for DOI 10.1513/AnnalsATS.201802-146OC
View details for Web of Science ID 000447989500008
View details for PubMedID 29877714
Diagnostic yield of bronchoalveolar lavage in immunocompromised children with malignant and non-malignant disorders.
The diagnostic yield of bronchoalveolar lavage (BAL) in the Immunocompromised pediatric population has ranged from 28% to 68%. We hypothesized that the diagnostic yield of BALs would be higher in more recent years due to new diagnostic assays.A retrospective case series was performed among immunocompromised children ≤18 years old who underwent BALs from 2001 to 2012, to assess the yield of microbiologic diagnostic studies and to determine the impact of BAL findings on antimicrobial management.In all, 123 subjects underwent 174 BALs (mean age 9.9 years). Underlying diagnoses included both malignant (n = 79) and non-malignant (n = 44) disorders, and 75 (61.0%) subjects were hematopoietic stem cell transplant (HSCT) recipients. Fifty-four (31.0%) of 174 BAL were positive for ≥1 potential pathogen (n = 58 microorganisms). The diagnostic yield of BALs performed from 2001 to 2006 versus2007-2012 was similar (40.5% vs. 26.6%, respectively, P = 0.07). Most subjects (86.2%) were on ≥1 antimicrobial at the time of BAL. Most (65.8%) negative BALs were associated with narrowing antimicrobial therapy, while most (74.1%) positive BALs were associated with continuing or changing to targeted antimicrobial therapy.In this study population, the diagnostic yield of BAL was similar to that previously described and unchanged in more recent years. Both negative and positive BALs were associated with changes in antimicrobial management.A 10-year retrospective review of bronchoalveolar lavage in 123 immunocompromised children determined that the rate of isolation of potential pathogens was 31% in this population. The majority of BAL was associated with a change in antimicrobial therapy. Pediatr Pulmonol. © 2016 Wiley Periodicals, Inc.
View details for DOI 10.1002/ppul.23644
View details for PubMedID 28052585
Improving case finding of invasive aspergillosis in children using string searches.
American journal of infection control
Surveillance for invasive Aspergillus (IA) in children is complex. We performed a retrospective study (2004-2013) using string searches of relevant terms within histopathology and radiology reports in efforts to improve detection of IA. Overall, 22 children met IA criteria, of whom 5 (23%) were only identified by string searches.
View details for DOI 10.1016/j.ajic.2016.04.230
View details for PubMedID 27375058
View details for PubMedCentralID PMC5135616
Congenital Parvovirus B19 Infection: Persistent Viremia and Red Blood Cell Aplasia.
Open forum infectious diseases
2015; 2 (2): ofv049-?
We describe a case of fetal parvovirus B19 infection resulting in preterm birth and leading to hydrops fetalis requiring multiple in utero transfusions. The infant developed chronic postnatal anemia responsive to intravenous immunoglobulin therapy. Serum viral load decreased after immunoglobulin treatment but remained detectable for over 1 year.
View details for DOI 10.1093/ofid/ofv049
View details for PubMedID 26288800
View details for PubMedCentralID PMC4539735
Fever, Emesis, Abdominal Pain, and Pancytopenia in a 16-Year-Old Girl
PEDIATRIC INFECTIOUS DISEASE JOURNAL
2009; 28 (10): 931-?
View details for DOI 10.1097/INF.0b013e3181bbb6e3
View details for Web of Science ID 000270407800021
View details for PubMedID 20118687