We have evaluated the serum response to seasonal influenza vaccination in subjects of different ages and associated this with the specific B cell response to the vaccine in vitro. Although the serum response has previously been shown to decrease with age, this has largely been associated to decreased T cell functions. Our results show that in response to the vaccine, the specific response of B cells in vitro, as measured by AID (activation-induced cytidine deaminase), the in vivo serum HI (hemagglutination inhibition) response, and the in vivo generation of switch memory B cells are decreased with age, as evaluated in the same subjects. This is the first report to demonstrate that intrinsic B cell defects with age contribute to reduced antibody responses to the influenza vaccine. The level of AID in response to CpG before vaccination can also predict the robustness of the vaccine response. These results could contribute to developing more effective vaccines to protect the elderly as well as identifying those most at risk.

In order to develop predictive markers for a beneficial humoral immune response, we evaluated the in vivo and in vitro response to the pandemic (p)H1N1 vaccine in young and elderly individuals. We measured serum antibody response and associated this with the in vitro B-cell response to the vaccine, measured by activation-induced cytidine deaminase (AID). Both responses decrease with age and are significantly correlated. The percentage of switched memory B cells in blood, both before and after vaccination, is decreased with age. The percentage of switched memory B cells at t0 correlates with the hemagglutination inhibition response and therefore, we suggest that this may be used as a predictive marker for B-cell responsiveness. AID induced by CpG before vaccination also predicts the robustness of the vaccine response. Plasmablasts showed a trend to increase after vaccination in young individuals only. This report establishes molecular biomarkers of response, percentage of switched memory B cells and AID response to CpG, useful for identifying individuals at risk of poor response and also for measuring improvements in vaccines and monitoring optimal humoral responses.

Background: Pediatric vascular access is inherently challenging due to the small caliber of children's vessels. Ultrasound-guided intravenous catheter insertion has been shown to increase success rates and decrease time to cannulation in patients with difficult intravenous access. Although proficiency in ultrasound-guided intravenous catheter insertion is a critical skill in pediatric anesthesia, there are no published competency-based training curricula. Aims: The objective of this study was to evaluate the performance of pediatric anesthesiologists who participated in a novel ultrasound-guided intravenous catheter insertion simulation-based mastery learning curriculum. Methods: Pediatric anesthesia attendings, fellows, and rotating residents participated in the ultrasound-guided intravenous catheter insertion simulation-based mastery learning curriculum from August 2019 to February 2020. The 2-hour curriculum consisted of participants first undergoing a simulated skills pretest followed by watching a video on ultrasound-guided intravenous catheter insertion and deliberate practice on a simulator. Subsequently, all participants took a post-test and were required to meet or exceed a minimum passing standard. Those who were unable to meet the minimum passing standard participated in further practice until they could be retested and met this standard. We compared pre to post-test ultrasound-guided intravenous catheter insertion skills and self-confidence before and after participation in the curriculum. Results: Twenty-six pediatric anesthesia attendings, 12 fellows, and 38 residents participated in the curriculum. At pretest, 16/76 (21%) participants were able to meet or exceed the minimum passing standard. The median score on the pretest was 21/25 skills checklist items correct and improved to 24/25 at post-test (95% CI 3.0-4.0, P < .01). Self-confidence significantly improved after the course from an average of 3.2 before the course to a postcourse score of 3.9 (95% CI 0.5-0.9, P < .01; 1 = Not all confident, 5 = Very confident). Conclusions: Simulation-based mastery learning significantly improved anesthesiologists' ultrasound-guided intravenous catheter insertion performance in a simulated setting.

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