The association of Torque Teno viral load with CMV and BKV infection in pediatric and adolescent kidney transplant patients.

BACKGROUND: Long-term allograft and patient survival after kidney transplantation (KTX) depends on the balance between over- and under-immunosuppression (IS). High levels of IS predispose to opportunistic infections. Plasma load of Torque Teno Virus (TTV), a non-pathogenic highly prevalent Annellovirus, is associated with its hosts immune status, especially after solid organ transplantation. OBJECTIVES: To investigate the association of plasma TTV load and opportunistic viral infections after pediatric KTX. STUDY DESIGN: This retrospective study includes all pediatric KTX patients followed at the Medical University of Vienna 2014-2020. PCR for Cytomegalovirus (CMV), Epstein-Barr virus (EBV), BK virus (BKV), and TTV was performed every 4-8 weeks at routine follow-up visits. RESULTS: 71 pediatric KTX patients were followed with TTV measurements for a median of 2.7 years. TTV plasma load was associated with CMV DNAemia at the next visit with an OR of 2.37 (95 % CI 1.15-4.87; p = 0.03) after adjustment for time after KTX and recipient age. For a cut-off of 7.68 log10 c/mL TTV a sensitivity of 100 %, a specificity of 61 %, a NPV 100 %, and a PPV of 46 % to detect CMV DNAemia at the next visit was calculated. TTV plasma loads were also associated with BKV DNAuria and BKV DNAemia at the next visit, but not with EBV DNAemia. CONCLUSIONS: This is the first study to analyse associations between TTV plasma loads and opportunistic viral infections in pediatric KTX. We were able to present a TTV cut-off for the prediction of clinically relevant CMV DNAemia that might be useful in clinical care.

Life outcomes after paediatric kidney transplantation: a qualitative, biographical study in long-term survivors.

OBJECTIVE: The objective of this study was to analyse the narrative life stories of children with end-stage kidney disease (ESKD) and their families to determine how health professionals can effectively support these children to achieve better life outcomes. DESIGN: Qualitative narrative biographic study. SETTING: We invited every long-term survivor of paediatric kidney transplants and their families at the Medical University of Vienna between 2008 and 2013 to participate in this study. PARTICIPANTS: Nineteen patients (women: n=8, 42%) and 34 family members (women: n=22, 65%) were interviewed. The patients had a mean age of 7.6 (SD±5.6) years at the time of transplantation and 22.2 (SD±5.4) at the time of interview. MAIN OUTCOMES MEASURES: A qualitative narrative biographical analysis was combined with computational structured topic models using the Latent Dirichlet Allocation. RESULTS: The overarching finding was the desire for normality in daily life in long-term survivors and their families but with different perceptions of what normality looks like and predominance of this aspect evolving. Different strategies were used by patients (focused on their advancement) and caregivers (normality for all family members). Siblings played a major role in supporting survivors' social inclusion. CONCLUSIONS: The strong desire for normality confirms recent findings of the Standardised Outcomes in Nephrology Group initiative, which proposes survival and life participation as core outcomes in children with chronic kidney disease. Our study should be a starting point for an international effort to identify typologies and stratified interventions for children with ESKD and their families, particularly siblings.

Parents' understanding of medication at discharge and potential harm in children with medical complexity.

OBJECTIVE: Children with medical complexity (CMC) are among the most vulnerable patient groups. This study aimed to evaluate their prevalence and risk factors for medication misunderstanding and potential harm (PH) at discharge. DESIGN AND SETTING: Cross-sectional study at a tertiary care centre. STUDY POPULATION: CMC admitted at Medical University of Vienna between May 2018 and January 2019. INTERVENTION: CMC and caregivers underwent a structured interview at discharge; medication understanding and PH for adverse events were assessed by a hybrid approach. MAIN OUTCOME MEASURES: Medication misunderstanding rate; PH. RESULTS: For 106 included children (median age 9.6 years), a median number of 5.0 (IQR 3.0-8.0) different medications were prescribed. 83 CMC (78.3%) demonstrated at least one misunderstanding, in 33 CMC (31.1%), potential harm was detected, 5 of them severe. Misunderstandings were associated with more medications (r=0.24, p=0.013), new prescriptions (r=0.23, p=0.019), quality of medication-related communication (r=-0.21, p=0.032), low level of education (p=0.013), low language skills (p=0.002) and migratory background (p=0.001). Relative risk of PH was 2.27 times increased (95% CI 1.23 to 4.22) with new medications, 2.14 times increased (95% CI 1.10 to 4.17) with migratory background. CONCLUSION: Despite continuous care at a tertiary care centre and high level of subjective satisfaction, high prevalence of medication misunderstanding with relevant risk for PH was discovered in CMC and their caregivers. This demonstrates the need of interventions to improve patient safety, with stratification of medication-related communication for high-risk groups and a restructured discharge process focusing on detection of misunderstandings ('unknown unknowns').

Computational drug repositioning of clopidogrel as a novel therapeutic option for focal segmental glomerulosclerosis.

Focal segmental glomerulosclerosis (FSGS) is a glomerular lesion often associated with nephrotic syndrome. It is also associated with a high risk of progression to end-stage kidney disease. Current treatment of FSGS is limited to systemic corticosteroids or calcineurin inhibition, along with inhibitors of the renin-angiotensin-aldosterone system. FSGS is heterogeneous in etiology, and novel therapies targeting specific, dysregulated molecular pathways represent a major unmet medical need. We have generated a network-based molecular model of FSGS pathophysiology using previously established systems biology workflows to allow computational evaluation of compounds for their predicted interference with molecular processes contributing to FSGS. We identified the anti-platelet drug clopidogrel as a therapeutic option to counterbalance dysregulated FSGS pathways. This prediction of our computational screen was validated by testing clopidogrel in the adriamycin FSGS mouse model. Clopidogrel improved key FSGS outcome parameters and significantly reduced urinary albumin to creatinine ratio (P < 0.01) and weight loss (P < 0.01), and ameliorated histopathological damage (P < 0.05). Clopidogrel is used to treat several cardiovascular diseases linked to chronic kidney disease. Clopidogrel's favorable safety profile and its efficacy in the adriamycin mouse FSGS model thus recommend it as an attractive drug repositioning candidate for clinical trial in FSGS.

Sodium intake and urinary losses in children on dialysis: a European multicenter prospective study.

BACKGROUND: Sodium (Na) balance is unexplored in dialyzed children. We assessed a simplified sodium balance (sNaB) and its correlates in pediatric patients receiving maintenance dialysis. METHODS: Patients < 18 years old on hemodialysis (HD) or peritoneal dialysis (PD) in six European Pediatric Dialysis Working Group centers were recruited. sNaB was calculated from enteral Na, obtained by a 3-day diet diary, Na intake from medications, and 24-h urinary Na (uNa). Primary outcomes were systolic blood pressure and diastolic blood pressure standard deviation scores (SBP and DBP SDS), obtained by 24-h ambulatory blood pressure monitoring or office BP according to age, and interdialytic weight gain (IDWG). RESULTS: Forty-one patients (31 HD), with a median age of 13.3 (IQR 5.2) years, were enrolled. Twelve patients (29.3%) received Na-containing drugs, accounting for 0.6 (0.7) mEq/kg/day. Median total Na intake was 1.5 (1.1) mEq/kg/day, corresponding to 60.6% of the maximum recommended daily intake for healthy children. Median uNa and sNaB were 0.6 (1.8) mEq/kg/day and 0.9 (1.7) mEq/kg/day, respectively. The strongest independent predictor of sNaB in the cohort was urine output. In patients receiving HD, sNaB correlated with IDWG, pre-HD DBP, and first-hour refill index, a volume index based on blood volume monitoring. sNaB was the strongest predictor of IDWG in multiple regression analysis (ß = 0.63; p = 0.005). Neither SBP SDS nor DBP SDS correlated with sNaB. CONCLUSIONS: Na intake is higher than uNa in children on dialysis, and medications may be an important source of Na. sNaB is best predicted by urine output in the population, and it is a significant independent predictor of IDWG in children on HD. A higher resolution version of the Graphical abstract is available as Supplementary information.

In-Depth Analysis of the Extracorporeal Proteome Adsorbed to Dialysis Membranes during Hemodialysis.

Used hemodialysis membranes (HD-M) are a valuable reservoir of biological information. Proteins bind to HD-M, but whether this process depends on the type of membrane or patient factors or selectively affects specific protein classes has not been adequately elucidated. State-of-the-art proteomics techniques are capable of identifying and quantifying this therapy-specific subproteome to enable the analysis of disease- or membrane-induced pathophysiologies. We demonstrate the feasibility of the deep proteomic characterization of the extracorporeal proteome adsorbed to HD-M. A shotgun proteomics approach using nano-flow liquid chromatography coupled to mass-spectrometry identified 1648 unique proteins eluted by a chaotropic buffer from the HD-M of eight patients. In total, 995 proteins were present in all eluates; a more stringent approach showed that a core proteome of 310 proteins could be identified independently in all samples. Stability of the dialyzer proteome was demonstrated by a >90% re-identification rate on longitudinal samples of a single patient. The core proteome showed an overrepresentation of pathways of hemostasis and the immune system, and showed differences in membrane materials (polysulfone vs. helixone). This study demonstrates that optimized conditions combined with high-performance proteomics enable the in-depth exploration of the subproteome bound to HD-M, yielding a stable core proteome that can be exploited to study patient-specific factors and improve hemodialysis therapy.

Targeted Training for Subspecialist Care in Children With Medical Complexity.

Background: Children with medical complexity (CMC) are prone to medical errors and longer hospital stays, while residents do not feel prepared to provide adequate medical care for this vulnerable population. No educational guidance for the training of future pediatric tertiary care specialists outside their field of expertise involving the multidisciplinary care of CMC exists. We investigated pediatric residents past educational needs and challenges to identify key learning content for future training involving care for CMC. Methods: This was a prospective mixed-methods study at a single pediatric tertiary care center. Qualitative semi-structured interviews with residents were conducted, submitted to thematic content analysis, linked to the American Board of Pediatrics (ABP) general pediatrics content outline, and analyzed with importance performance analysis (IPA). Quantitative validation was focused on key themes of pediatric nephrology within the scope of an online survey among pediatric residents and specialists. Results: A total of 16 interviews, median duration 69 min [interquartile range IQR 35], were conducted. The 280 listed themes of the ABP general pediatrics content outline were reduced to 165 themes, with 86% (theoretical) knowledge, 12% practical skills, and 2% soft skills. IPA identified 23 knowledge themes to be of high importance where improvement is necessary and deemed fruitful. Quantitative validation among 84 residents and specialists (response rate 55%) of key themes in nephrology yielded high agreement among specialists in pediatric nephrology but low interrater agreement among trainees and "trained" non-nephrologists. The occurrence of themes in the qualitative interviews and their calculated importance in the quantitative survey were highly correlated (tau = 0.57, p = 0.001). Two clusters of high importance for other pediatric specialties emerged together with a contextual cluster of frequent encounters in both in- and outpatient care. Conclusion: Regarding patient safety, this study revealed the heterogeneous aspects and the importance of training future pediatric tertiary care specialists outside their field of expertise involving the multidisciplinary care of CMC. Our results may lay the groundwork for future detailed analysis and development of training boot camps that might be able to aid the improvement of patient safety by decreasing preventable harm by medical errors, especially for vulnerable patient groups, such as CMC in tertiary care pediatrics.

Mandatory Vaccination Against COVID-19: Twitter Poll Analysis on Public Health Opinion.

BACKGROUND: On January 30, 2020, the World Health Organization Emergency Committee declared the rapid worldwide spread of COVID-19 a global health emergency. By December 2020, the safety and efficacy of the first COVID-19 vaccines had been demonstrated. However, international vaccination coverage rates have remained below expectations (in Europe at the time of manuscript submission). Controversial mandatory vaccination is currently being discussed and has already been introduced in some countries (Austria, Greece, and Italy). We used the Twitter survey system as a viable method to quickly and comprehensively gather international public health insights on mandatory vaccination against COVID-19. OBJECTIVE: The purpose of this study was to better understand the public's perception of mandatory COVID-19 vaccination in real time using Twitter polls. METHODS: Two Twitter polls were developed (in the English language) to seek the public's opinion on the possibility of mandatory vaccination. The polls were pinned to the Digital Health and Patient Safety Platform's (based in Vienna, Austria) Twitter timeline for 1 week in mid-November 2021, 3 days after the official public announcement of mandatory COVID-19 vaccination in Austria. Twitter users were asked to participate and retweet the polls to reach the largest possible audience. RESULTS: Our Twitter polls revealed two extremes on the topic of mandatory vaccination against COVID-19. Almost half of the 2545 respondents (n=1246, 49%) favor mandatory vaccination, at least in certain areas. This attitude contrasts with the 45.7% (n=1162) who categorically reject mandatory vaccination. Over one-quarter (n=621, 26.3%) of participating Twitter users said they would never get vaccinated, as reflected by the current Western European and North American vaccination coverage rate. Concatenating interpretation of these two polls should be done cautiously as participating populations might substantially differ. CONCLUSIONS: Mandatory vaccination against COVID-19 (in at least certain areas) is favored by less than 50%, whereas it is opposed by almost half of the surveyed Twitter users. Since (social) media strongly influences public perceptions and views, and social media discussions and surveys are specifically susceptible to the "echo chamber effect," the results should be interpreted as a momentary snapshot. Therefore, the results of this study need to be complemented by long-term surveys to maintain their validity.

Assessing mechanical catheter dysfunction in automated tidal peritoneal dialysis using cycler software: a case control, proof-of-concept study.

New recommendations on evaluation of peritoneal membrane function suggest ruling out catheter dysfunction when evaluating patients with low ultrafiltration capacity. We introduce the use of a combination of parameters obtained from the cycler software PD Link with HomeChoicePro (Baxter International Inc., Illinois, United States) cyclers for predicting catheter dysfunction in automated peritoneal dialysis patients (APD). Out of 117 patients treated at the Medical University of Vienna between 2015 and 2021, we retrospectively identified all patients with verified catheter dysfunction (n = 14) and compared them to controls without clinical evidence of mechanical catheter problems and a recent X-ray confirming PD catheter tip in the rectovesical/rectouterine space (n = 19). All patients had a coiled single-cuff PD catheter, performed tidal PD, and received neutral pH bicarbonate/lactate-buffered PD fluids with low-glucose degradation products on APD. Icodextrin-containing PD fluids were used for daytime dwells. We retrieved cycler data for seven days each and tested parameters' predictive capability of catheter dysfunction. Total number of alarms/week > 7 as single predictive parameter of catheter dislocation identified 85.7% (sensitivity) of patients with dislocated catheter, whereas 31.6% (1-specificity) of control patients were false positive. A combination of parameters (number of alarms/week > 7, total drain time > 22 min, ultrafiltration of last fill < 150 mL) where at least two of three parameters appeared identified the same proportion of patients with catheter dislocation, but was more accurate in identifying controls (21.1% false positive). In contrast to yearly PET measurements, an easily applicable combination of daily cycler readout parameters, also available in new APD systems connected to remote monitoring platforms shows potential for diagnosis of catheter dysfunction during routine follow-up.

Saliva Sampling for Prospective SARS-CoV-2 Screening of Healthcare Professionals.

OBJECTIVE: The objective of this study was to analyze the feasibility and acceptance of a non-invasive, daily and proactive screening program for SARS-CoV-2 infection employing serial saliva testing, in combination with a digital questionnaire among healthcare providers (HCPs) in a multi-professional setting. DESIGN: This was a prospective cohort study involving HCPs from different units at a single tertiary care center, over a pilot phase of 4 weeks during the first wave of the COVID-19 pandemic from April 18th to June 6th, 2020. SETTING: Pediatric tertiary patient care units, Comprehensive Center for Pediatrics, Medical University of Vienna. SUBJECTS: HCPs from different units, including physicians, nurses, midwives, and administrative staff (with patient contact) were considered eligible for the study. Study participants were working in different settings in our center at varying levels of risk exposure. INTERVENTIONS: Saliva collection from mouth gargle and electronic symptom and exposure monitoring (eSEM) was performed by participants at the onset of each regular clinical shift (day or night shift), using an anonymous ID for matching the results. MEASUREMENTS: RT-PCR of all saliva samples, eSEM, as well as feasibility and acceptance thereof. RESULTS: Two hundred and seventy-five volunteers collected 1,865 saliva samples and responded 1,378 times in the eSEM during a 4-week period. 1,331 (96.7%) responses were that the testing was feasible and acceptable. The most common severe symptom during the 4-week period mentioned by HCPs was headache, reported 54 times (3.9%). Two SARS-CoV-2 positive samples-one of them being associated with symptoms-were identified. The acceptance rate among HCPs was 96.6%. CONCLUSION: Serial saliva screening was a well-accepted and feasible method for monitoring SARS-CoV-2 infectious state in health care professionals. Combination of regular SARS-CoV-2 tests with sequential saliva collection and storage could potentially represent a highly efficient strategy to identify and trace virus positive staff for employee and patient safety.

Kidney Transplantation in Small Children: Association Between Body Weight and Outcome-A Report From the ESPN/ERA-EDTA Registry.

BACKGROUND: Many centers accept a minimum body weight of 10 kg as threshold for kidney transplantation (Tx) in children. As solid evidence for clinical outcomes in multinational studies is lacking, we evaluated practices and outcomes in European children weighing below 10 kg at Tx. METHODS: Data were obtained from the European Society of Paediatric Nephrology/European Renal Association and European Dialysis and Transplant Association Registry on all children who started kidney replacement therapy at <2.5 y of age and received a Tx between 2000 and 2016. Weight at Tx was categorized (<10 versus ≥10 kg) and Cox regression analysis was used to evaluate its association with graft survival. RESULTS: One hundred of the 601 children received a Tx below a weight of 10 kg during the study period. Primary renal disease groups were equal, but Tx <10 kg patients had lower pre-Tx weight gain per year (0.2 versus 2.1 kg; P < 0.001) and had a higher preemptive Tx rate (23% versus 7%; P < 0.001). No differences were found for posttransplant estimated glomerular filtration rates trajectories (P = 0.23). The graft failure risk was higher in Tx <10 kg patients at 1 y (graft survival: 90% versus 95%; hazard ratio, 3.84; 95% confidence interval, 1.24-11.84), but not at 5 y (hazard ratio, 1.71; 95% confidence interval, 0.68-4.30). CONCLUSIONS: Despite a lower 1-y graft survival rate, graft function, and survival at 5 y were identical in Tx <10 kg patients when compared with Tx ≥10 kg patients. Our results suggest that early transplantation should be offered to a carefully selected group of patients weighing <10 kg.

Lithium preserves peritoneal membrane integrity by suppressing mesothelial cell αB-crystallin.

Life-saving renal replacement therapy by peritoneal dialysis (PD) is limited in use and duration by progressive impairment of peritoneal membrane integrity and homeostasis. Preservation of peritoneal membrane integrity during chronic PD remains an urgent but long unmet medical need. PD therapy failure results from peritoneal fibrosis and angiogenesis caused by hypertonic PD fluid (PDF)-induced mesothelial cytotoxicity. However, the pathophysiological mechanisms involved are incompletely understood, limiting identification of therapeutic targets. We report that addition of lithium chloride (LiCl) to PDF is a translatable intervention to counteract PDF-induced mesothelial cell death, peritoneal membrane fibrosis, and angiogenesis. LiCl improved mesothelial cell survival in a dose-dependent manner. Combined transcriptomic and proteomic characterization of icodextrin-based PDF-induced mesothelial cell injury identified αB-crystallin as the mesothelial cell protein most consistently counter-regulated by LiCl. In vitro and in vivo overexpression of αB-crystallin triggered a fibrotic phenotype and PDF-like up-regulation of vascular endothelial growth factor (VEGF), CD31-positive cells, and TGF-ß-independent activation of TGF-ß-regulated targets. In contrast, αB-crystallin knockdown decreased VEGF expression and early mesothelial-to-mesenchymal transition. LiCl reduced VEGF release and counteracted fibrosis- and angiogenesis-associated processes. αB-crystallin in patient-derived mesothelial cells was specifically up-regulated in response to PDF and increased in peritoneal mesothelial cells from biopsies from pediatric patients undergoing PD, correlating with markers of angiogenesis and fibrosis. LiCl-supplemented PDF promoted morphological preservation of mesothelial cells and the submesothelial zone in a mouse model of chronic PD. Thus, repurposing LiCl as a cytoprotective PDF additive may offer a translatable therapeutic strategy to combat peritoneal membrane deterioration during PD therapy.

Influenza and pneumococcus vaccination rates in pediatric dialysis patients in Europe: recommendations vs reality A European Pediatric Dialysis Working Group and European Society for Pediatric Nephrology Dialysis Working Group study

Background/aim: Children on dialysis are under increased risk of influenza and invasive pneumococcal disease. Although vaccination against these microorganisms are recommended in dialysis patients and despite the fact that these vaccines can reduce disease burden and rates of hospitalization due to infection, vaccination rates are below expected and desired. We aimed to evaluate influenza and pneumococcal vaccination and infection rates in European pediatric dialysis centers. Materials and methods: In 16 centers from 11 countries, 357 pediatric dialysis patients were evaluated retrospectively during 1 year of observation period between 01.01.2014 and 01.01.2015. Results: In all centers, vaccination policy included immunization of dialysis patients with inactive influenza vaccine and pneumococcal conjugate vaccine (PCV). Fifty percent of the centers recommended pneumococcal polysaccharide vaccine following routine PCV series. A significantly higher pneumococcal vaccination rate (43.9%) was seen in peritoneal dialysis (PD) patients compared to those on hemodialysis (HD) (32.9%) (p = 0.035), while the rates for influenza were similar (42.4% and 46.1% respectively, p = 0.496). Among all dialysis patients, 2.2% (n = 8) developed pneumonia and 6.4% (n = 23) was infected by Influenza. Pneumococcic pneumonia rate was 5% for 140 patients who received antipneumococcal vaccine, while only one pneumonia episode was recorded out of 217 unvaccinated patients (p = 0.007). The influenza virus infection rates were similar for patients vaccinated and nonvaccinated (7 % and 6 %, respectively). Conclusions: Although influenza and pneumococcal vaccines are highly recommended in pediatric dialysis patients, vaccination rates were lower than expected. Pneumococcal vaccination rates were higher in PD compared to the patients on HD. The rate of children with influenza infection was higher than pneumonia. The efficacy of influenza and pneumococcal vaccines was highlighted by the low infection rates. Higher pneumonia rates in patients vaccinated against pneumococcus compared to unvaccinated ones might be due to coexisting risk factors.

Recessive NOS1AP variants impair actin remodeling and cause glomerulopathy in humans and mice.

Nephrotic syndrome (NS) is a leading cause of chronic kidney disease. We found recessive NOS1AP variants in two families with early-onset NS by exome sequencing. Overexpression of wild-type (WT) NOS1AP, but not cDNA constructs bearing patient variants, increased active CDC42 and promoted filopodia and podosome formation. Pharmacologic inhibition of CDC42 or its effectors, formin proteins, reduced NOS1AP-induced filopodia formation. NOS1AP knockdown reduced podocyte migration rate (PMR), which was rescued by overexpression of WT Nos1ap but not by constructs bearing patient variants. PMR in NOS1AP knockdown podocytes was also rescued by constitutively active CDC42Q61L or the formin DIAPH3 Modeling a NOS1AP patient variant in knock-in human kidney organoids revealed malformed glomeruli with increased apoptosis. Nos1apEx3-/Ex3- mice recapitulated the human phenotype, exhibiting proteinuria, foot process effacement, and glomerulosclerosis. These findings demonstrate that recessive NOS1AP variants impair CDC42/DIAPH-dependent actin remodeling, cause aberrant organoid glomerulogenesis, and lead to a glomerulopathy in humans and mice.

Countermeasures against COVID-19: how to navigate medical practice through a nascent, evolving evidence base - a European multicentre mixed methods study.

OBJECTIVES: In a previously published Delphi exercise the European Pediatric Dialysis Working Group (EPDWG) reported widely variable counteractive responses to COVID-19 during the first week of statutory public curfews in 12 European countries with case loads of 4-680 infected patients per million. To better understand these wide variations, we assessed different factors affecting countermeasure implementation rates and applied the capability, opportunity, motivation model of behaviour to describe their determinants. DESIGN: We undertook this international mixed methods study of increased depth and breadth to obtain more complete data and to better understand the resulting complex evidence. SETTING: This study was conducted in 14 paediatric nephrology centres across 12 European countries during the COVID-19 pandemic. PARTICIPANTS: The 14 participants were paediatric nephrologists and EPDWG members from 12 European centres. MAIN OUTCOME MEASURES: 52 countermeasures clustered into eight response domains (access control, patient testing, personnel testing, personal protective equipment policy, patient cohorting, personnel cohorting, suspension of routine care, remote work) were categorised by implementation status, drivers (expert opinion, hospital regulations) and resource dependency. Governmental strictness and media attitude were independently assessed for each country and correlated with relevant countermeasure implementation factors. RESULTS: Implementation rates varied widely among response domains (median 49.5%, range 20%-71%) and centres (median 46%, range 31%-62%). Case loads were insufficient to explain response rate variability. Increasing case loads resulted in shifts from expert opinion-based to hospital regulation-based decisions to implement additional countermeasures despite increased resource dependency. Higher governmental strictness and positive media attitude towards countermeasure implementation were associated with higher implementation rates. CONCLUSIONS: COVID-19 countermeasure implementation by paediatric tertiary care centres did not reflect case loads but rather reflected heterogeneity of local rules and of perceived resources. These data highlight the need of ongoing reassessment of current practices, facilitating rapid change in 'institutional behavior' in response to emerging evidence of countermeasure efficacy.