Coronavirus disease 2019 vaccine in pediatric post-kidney transplantation.

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections and the resulting disease, coronavirus disease 2019 (COVID-19), have spread to millions of persons worldwide. Many vaccines have been developed; however, their efficacy in pediatric solid organ transplant recipients is yet to be determined. METHODS: This is a prospective observational, non-interventional single-center study on the safety and efficacy of a COVID-19 vaccine (BNT162b2) in pediatric kidney transplant recipients. The primary aim of this study was to evaluate immunogenicity according to SARS-CoV-2-specific neutralizing antibody titer after two vaccine doses. The secondary aims were to investigate the safety of the vaccines, solicited local and systemic adverse reactions, incidence of COVID-19 post-vaccination, and effects on transplant graft function. Baseline investigations were conducted on pediatric renal transplant recipients, and recruited participants were advised to have the Comirnaty® mRNA vaccine according to protocol. RESULTS: A total of 48 patients (male, n = 31, 64.6%; female, n = 17, 35.4%), median age 14 [12-16] years were included, and all received two doses of the vaccine. The vaccine had a favorable safety and side-effect profile. The S-antibody titer of all patients ranged between .4 and 2,500 U/ml and was > 50 U/ml in 89% of the patients. No difference in the measured antibody immune response was noted between infected and uninfected children. No major side effects were reported. CONCLUSION: The vaccine had a favorable safety profile in 12- to 15-year-old kidney transplant recipients, producing a greater measured antibody response than that in older transplant recipients.

Vasculature reconstruction of decellularized liver scaffolds via gelatin-based re-endothelialization.

Decellularized liver scaffolds based liver engineering is a promising approach toward developing functional liver surrogates. However, a major obstacle to long-term transplantation is the hemocompatibility of the bioengineered liver surrogates. One approach to improve the hemocompatibility of engineered liver surrogates is re-endothelialization. In the current study, immortalized endothelial cells were perfused for re-endothelialization of decellularized rat liver scaffolds. When compared to the media-based perfusion approach, gelatin hydrogels-based perfusion significantly increased the number of cells that were retained in the decellularized liver scaffolds and the vascular lumen coverage ratio. Endothelial cells were lining along the vasculatures of the decellularized liver scaffolds and actively proliferating. Re-endothelialization improved the blood retention ability of the liver scaffold vasculatures. Doppler ultrasound detected active blood flows within the re-endothelialized liver scaffold transplants 8 days post-transplantation. Our results strengthened the feasibility of developing bioengineered liver surrogates utilizing decellularized liver scaffolds. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 392-402, 2019.

Whole liver engineering: A promising approach to develop functional liver surrogates.

Liver donor shortage remains the biggest challenge for patients with end-stage liver failures. While bioartificial liver devices have been developed as temporary supports for patients waiting for transplantation, their applications have been limited clinically. Whole liver engineering is a biological scaffold based regenerative medicine approach that holds promise for developing functional liver surrogates. Significant advancements have been made since the first report in 2010. This review focuses on the recent achievements of whole liver engineering studies.

Neisseria meningitidis nasopharyngeal carriage during the Hajj: A cohort study evaluating the need for ciprofloxacin prophylaxis.

BACKGROUND: The annual Muslim pilgrimage has the potential of increase risk for acquisition of Neisseria meningitidis. Here, we evaluate the Hajj impact on the prevalence of N. meningitidis carriage in a paired and non-paired cohort of pilgrims. Secondary objectives were to calculate the compliance with recommended vaccination. METHODS: This is a prospective paired (arriving and departing), non-paired arriving and non-paired departing cohort study with the collection of nasopharyngeal samples at the start and the end of the Hajj. RESULTS: The study included unpaired arriving pilgrims at King Abdul Aziz International Airport (N=1055), unpaired departing cohort (N=373), and a paired cohort (N=628) who were tested on arrival and departure. Meningococcal vaccination was received by all pilgrims, 98.2% received quadrivalent polysaccharide vaccine (ACWY), and 1.8% received meningococcal quadrivalent conjugate vaccine (MCV4). Only 1.61% and 23.03% received pneumococcal and influenza vaccines, respectively. Of the 1055 arriving unpaired pilgrim, 36 (3.4%) tested positive for nasopharyngeal carriage of N. meningitidis, and 24 (66.7%) of these were serogroup B, the remainder were non-groupable. Haemophilus influenza was detected among 45 (4.3%), and 11 (1%) carriers were positive for both N. meningitidis and H. influenzae. Out of 373 in the unpaired departing cohort, 6 (1.61%) tested positive for N. meningitidis, and 34 (9.1%) were positive for H. influenzae. Of the 628 paired cohort pilgrims, 36 (5.7%) pilgrims were positive for N. meningitidis at arrival and 16 (2.5%) pilgrims were positive after the hajj. CONCLUSION: This the largest study of the epidemiology of N. meningitidis among pilgrims. The study showed a significant difference in the carriage between pilgrims from high endemicity and other pilgrims with a predominance of serogroup B. The continued use of ciprofloxacin as prophylactic antibiotics should be reconsidered as well as the consideration to add serogroup B as a required vaccination.

Outcome of strict implementation of infection prevention control measures during an outbreak of Middle East respiratory syndrome.

BACKGROUND: The objective of this retrospective cohort study was to assess the impact of implementation of different levels of infection prevention and control (IPC) measures during an outbreak of Middle East respiratory syndrome (MERS) in a large tertiary hospital in Saudi Arabia. The setting was an emergency room (ER) in a large tertiary hospital and included primary and secondary MERS patients. METHODS: Rapid response teams conducted repeated assessments of IPC and monitored implementation of corrective measures using a detailed structured checklist. We ascertained the epidemiologic link between patients and calculated the secondary attack rate per 10,000 patients visiting the ER (SAR/10,000) in 3 phases of the outbreak. RESULTS: In phase I, 6 primary cases gave rise to 48 secondary cases over 4 generations, including a case that resulted in 9 cases in the first generation of secondary cases and 21 cases over a chain of 4 generations. During the second and third phases, the number of secondary cases sharply dropped to 18 cases and 1 case, respectively, from a comparable number of primary cases. The SAR/10,000 dropped from 75 (95% confidence interval [CI], 55-99) in phase I to 29 (95% CI, 17-46) and 3 (95% CI, 0-17) in phases II and III, respectively. CONCLUSIONS: The study demonstrated salient evidence that proper institution of IPC measures during management of an outbreak of MERS could remarkably change the course of the outbreak.