Humoral and cellular response to the COVID-19 vaccine in immunocompromised children.

BACKGROUND: A suboptimal response to the 2-dose COVID-19 vaccine series in the immunocompromised population prompted recommendations for a 3rd primary dose. We aimed to determine the humoral and cellular immune response to the 3rd COVID-19 vaccine in immunocompromised children. METHODS: Prospective cohort study of immunocompromised participants, 5-21 years old, who received 2 prior doses of an mRNA COVID-19 vaccine. Humoral and CD4/CD8 T-cell responses were measured to SARS-CoV-2 spike antigens prior to receiving the 3rd vaccine dose and 3-4 weeks after the 3rd dose was given. RESULTS: Of the 37 participants, approximately half were solid organ transplant recipients. The majority (86.5%) had a detectable humoral response after the 2nd and 3rd vaccine doses, with a significant increase in antibody levels after the 3rd dose. Positive T-cell responses increased from being present in 86.5% to 100% of the cohort after the 3rd dose. CONCLUSIONS: Most immunocompromised children mount a humoral and cellular immune response to the 2-dose COVID-19 vaccine series, which is significantly augmented after receiving the 3rd vaccine dose. This supports the utility of the 3rd vaccine dose and the rationale for ongoing emphasis for vaccination against COVID-19 in this population. IMPACT: Most immunocompromised children mount a humoral and cellular immune response to the 2-dose COVID-19 vaccine series, which is significantly augmented after receiving the 3rd vaccine dose. This is the first prospective cohort study to analyze both the humoral and T-cell immune response to the 3rd COVID-19 primary vaccine dose in children who are immunocompromised. The results of this study support the utility of the 3rd vaccine dose and the rationale for ongoing emphasis for vaccination against COVID-19 in the immunosuppressed pediatric population.

Heart Rate Variability and Gastric Electrical Response to a Cold Pressor Task in Youth with Functional Dyspepsia.

BACKGROUND/AIMS: While stress has been implicated in functional dyspepsia (FD), the mechanisms by which stress results in symptoms are not well defined. The aim of the current study was to assess gastric myoelectric and autonomic changes in response to a physical stressor in youth with FD. METHODS: In a group of healthy controls and pediatric FD subjects, we recorded ECG and EGG signals 30 min before and 60 min after, a cold pressor task (CPT). Gastric EGG and heart rate variability (HRV) parameters were calculated in pre- and post-CPT stages and in short intervals. RESULTS: The pre-CPT percent tachygastria was higher in FD subjects as compared to controls. However, CPT did not induce any EGG changes in either controls or FD subjects and the two groups did not differ from each other post-CPT. The CPT resulted in an increase in HRV and standard deviation of NN intervals in controls; there was no change in any HRV parameter in FD subjects. CONCLUSIONS: Acute physical stress does not appear to induce gastric electrical abnormalities in youth with FD. Youth with FD appear to lack the normal flexible autonomic response to a physical stressor.

Pediatric Rome IV diagnosis agreement is greater than agreement on diagnostic testing.

BACKGROUND: Pediatric Rome IV criteria are used to diagnose childhood functional gastrointestinal disorders (FGIDs). This study of pediatric gastroenterology physicians measured their agreement in (1) Making a pediatric Rome IV FGID diagnosis; and (2) Diagnostic testing for patients with FGIDs. METHODS: Pediatric gastroenterologists and pediatric gastroenterology fellows at two medical centers completed a survey containing clinical FGID vignettes. For each vignette, raters identified the most likely Rome IV diagnosis(es) and selected which diagnostic test(s) (if any) they typically would obtain. The survey was re-administered within 3 months. Inter-rater and intra-rater weighted percent agreement was determined. Linear mixed modeling identified sources of variability in diagnostic testing. KEY RESULTS: Thirty-four raters completed the initial survey of whom thirty-one (91%) completed the repeat survey. Overall inter-rater agreement on Rome IV diagnoses was 68% for initial and repeat surveys whereas intra-rater agreement was 76%. In contrast, overall inter-rater agreement on diagnostic testing was <30% for both initial and repeat surveys and intra-rater agreement was only 57%. Between-physician differences accounted for 43% of the variability in the number of tests selected. Rater identified use of Rome criteria in clinical practice was associated with 1.1 fewer diagnostic tests on average (95% CI 0.2-2.0, p = 0.015). Higher intra-rater agreement was noted for diagnostic testing in faculty when compared to fellows (p = 0.009). CONCLUSIONS & INFERENCES: In a multicenter evaluation among pediatric gastroenterology physicians, pediatric Rome IV diagnostic agreement was higher than that reported for previous Rome versions, and higher than agreement on diagnostic testing.

Electrogastrographic and autonomic nervous system responses to solid and liquid meals in youth with functional dyspepsia.

BACKGROUND: Meal-related symptoms are common in paediatric functional dyspepsia (FD). There are only a small number of paediatric studies assessing mechanisms for meal-related symptoms, and these have not utilized Rome IV criteria. The aim of the current study was to assess gastric myoelectric and autonomic nervous system (ANS) responses to both liquid and solid meals in youth with Rome IV-defined FD. METHODS: In healthy controls (N = 14) and youth with FD (N = 12), we recorded electrocardiograph (to assess heart rate variability; HRV) and electrogastrograph (EGG) signals before and after two test meals, one liquid and one solid. EGG parameters and HRV were assessed for the entire pre- and postprandial periods and in short time intervals. Additionally, liquid gastric emptying was assessed utilizing a 13 C-acetate breath test. KEY RESULTS: During the EGG, the dominant power increased with both meals in controls but not patients with FD. During HRV assessment, the low frequency to high frequency ratio was higher after the liquid meal in controls, despite being similar preprandial, as compared to patients with FD. In controls, both standard deviation of normal to normal waves (SDNN) and root mean square of successive ECG R peaks (R-R interval) differences (rMSSD) increased after the liquid meal (but not after the solid meal) in controls but not patients with FD. CONCLUSIONS AND INFERENCES: Youth with Rome IV-defined FD lacks the normal postprandial EGG dominant power response or autonomic nervous system response following a liquid meal. The latter appears to indicate a lack of ANS flexibility.