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Background: Emerging evidence supports the importance of optimized antibiotic exposure in pediatric intensive care unit (PICU) patients. Traditional antibiotic dosing is not designed for PICU patients, as the extreme pharmacokinetic (PK) behavior of drugs threatens the achievement of optimal antibiotic treatment outcomes. Scavenged sampling is a sampling strategy which may have positive implications for routine TDM and PK research, as well as monitoring other biomarkers. EXPAT Kids study was designed to analyze whether current empiric dosing regimens of frequently used beta-lactam antibiotics achieve defined therapeutic target concentrations in PICU patients. Methods: A mono-centre, exploratory pharmacokinetic and pharmacodynamic study was designed to assess target attainment of beta-lactam antibiotics. One hundred forty patients will be included within 24 months after start of inclusion. At various time points serum concentration of the study antibiotic (cefotaxime, ceftazidime, ceftriaxone, cefuroxime, flucloxacillin, and meropenem) are determined. In parallel with these sampling moments, residual material is collected to validate the use of blood of scavenged heparinized astrup syringes for the quantification of antibiotic exposure. The primary outcome is the time that the free (unbound) concentration of the study antibiotic remains above one to four the minimal inhibitory concentration during a dosing interval (100%ƒT > MIC and 100%ƒT>4xMIC). Other included outcomes are disease severity, safety, length of stay, and inflammatory biomarkers. Discussion: Potentially, scavenged sampling may enrich the EXPAT Kids dataset, and reduce additional blood sampling and workload for clinical personnel. The findings from the EXPAT Kids study will lead to new insights in the PK parameters of beta-lactams and consecutive effects on target attainment and clinical outcomes. Is there a need for more precision in dosing? Netherlands Trial Register Number: Trial NL9326. [ABSTRACT FROM AUTHOR]

Roux-en-Y gastric bypass (RYGB) can cause multiple food intolerances and gastrointestinal complaints are frequently reported after dairy consumption. We aimed to determine the prevalence of lactose malabsorption and intolerance, and complaints associated with dairy consumption in daily life, before and after RYGB. The lactose breath test (LBT) and lactose tolerance test (LTT) was performed in 84 patients awaiting RYGB surgery and 84 patients after surgery. Gastrointestinal symptoms at baseline and after testing were recorded. Lactose malabsorption was defined as a positive LBT and/or LTT. Lactose intolerance as a positive test combined with an increase of gastrointestinal complains. Dairy consumption in daily life and successive gastrointestinal complaints were registered via a questionnaire. Results of preoperative and postoperative patients were compared. Lactose malabsorption was present in 15 (17.9%) of the preoperative patients and in 25 (29.8%) of the postoperative patients (OR 2.46; 95%CI: 1.08–5.59; p =.03). Of the preoperative patients 6 (7.1%) patients met the criteria for lactose intolerance, compared to 8 (9.5%) patients in the postoperative group (OR 1.48; 95%CI 0.48–4.57; p =.50). Twelve (14.3%) preoperative patients indicated to have gastrointestinal complaints after dairy consumption in daily life versus 45 (53.6%) postoperative patients (p <.01). This study shows no increase in patients with proven lactose intolerance after RYGB compared to preoperative patients. Gastrointestinal complaints after dairy consumption in daily life were far more frequently reported by RYGB patients. It is unlikely that all reported gastrointestinal complaints are actually caused by lactose. Other ingredients in dairy, like fat, are possibly contributory. [ABSTRACT FROM AUTHOR]

OBJECTIVES: Mechanical circulatory support (MCS) with a ventricular assist device (VAD) as a bridge to heart transplantation (HTx) or recovery may improve outcome in children with terminal heart failure. We report our experience with MCS in children eligible for HTx and its effect on waiting list mortality. METHODS: Retrospective single-centre cohort study, National Paediatric HTx Programme including all children eligible for HTx, since the introduction of MCS-VAD in 2006. RESULTS: A total of 43 patients were eligible for HTx, median age 11.7 years [Inter Quartile Range (IQR) 3.0–14.7]. In 18 patients, (42%) a VAD was implanted, 11 (61%) survived to HTx (n = 9) or recovery (n = 2). Techniques and devices used were left ventricular assist device (n = 16, 89%), in 4 cases preceded by extracorporeal membrane oxygenation (ECMO), and biventricular assist device (n = 2, 11%), both preceded by ECMO. In the VAD group, median time to death (n = 7) was 18 days (IQR 7–75), median time to HTx (n = 9) 66 days (IQR 33–223) and 2 patients recovered after 30 and 308 days. The main cause of death on MCS was neurological injury in 4 patients (22%) and systemic thrombo-embolic events in 2 (11%). The most common serious adverse events included confirmed thrombus requiring pump replacement (in 11 patients, 61%) and pericardial effusion leading to rethoracotomy (in 5 patients, 28%). Compared with the era before MCS (1998–2006), waiting list mortality decreased from 44 to 21%, and is now mainly related to complications of VAD support. CONCLUSIONS: Since the introduction of MCS-VAD, waiting list mortality halved and more children with end-stage heart failure survived to heart transplantation, thus improving outcome. Although there is substantial mortality and morbidity, overall mortality decreases, making MCS-VAD an essential therapeutic tool. The need for donor organs remains critically urgent. [ABSTRACT FROM AUTHOR]

Local vasoconstriction plays an important role in maintaining blood pressure in spinal cord-injured individuals (Sd). We aimed to unravel the mechanisms of local vasoconstriction [venoarteriolar reflex (VAR) and myogenic response] using both limb dependency and cuff inflation in SCI and compare these with control subjects. Limb blood flow was measured in 11 male SCI (age: 24-55 yr old) and 9 male controls (age: 23-56 yr old) using venous occlusion plethysmography in forearm and calf during three levels of 1) limb dependency, and 2) cuff inflation. During limb dependency, vasoconstriction relies on both the VAR and the myogenic response. During cuff inflation, the decrease in blood flow is caused by the VAR and by a decrease in arteriovenous pressure difference, whereas the myogenic response does not play a role. At the highest level of leg dependency, the percent increase in calf vascular resistance (mean arterial pressure/calf blood flow) was more pronounced in SCI than in controls (SCI 186 ± 53%; controls 51 ± 17%; P = 0.032). In contrast, during cuff inflation, no differences were found between SCI and controls (SCI 17 ± 17%; controls 14 ± 10%). Percent changes in forearm vascular resistance in response to either forearm dependency or forearm cuff inflation were equal in both groups. Thus local vasoconstriction during dependency of the paralyzed leg in SCI is enhanced. The contribution of the VAR to local vasoconstriction does not differ between the groups, since no differences between groups existed for cuff inflation. Therefore, the augmented local vasoconstriction in SCI during leg dependency relies, most likely, on the myogenic response. [ABSTRACT FROM AUTHOR]

OBJECTIVES: To assess the effect of administration of sodium bicarbonate on carbon dioxide levels in children with life-threatening asthma (LTA) and to evaluate the clinical effect of this treatment.Study DESIGN: Retrospective study. SETTING: A pediatric ICU (PICU) of a tertiary care university hospital. PATIENTS: Seventeen children with LTA who received sodium bicarbonate. MEASUREMENTS AND RESULTS: In January 1999, a new protocol for the treatment of LTA was initiated in our institution, incorporating the use of IV sodium bicarbonate in acidotic patients (pH < 7.15) with refractory status asthmaticus. Since January 1999, sodium bicarbonate was administered to 17 patients; 5 patients received two or three doses of sodium bicarbonate. In three patients, sodium bicarbonate was administered after intubation. Intubation and mechanical ventilation were performed in five patients before admission to the PICU, and in one patient during admission. There was a significant decrease of Pco(2) after sodium bicarbonate infusion (p = 0.007). An improvement of respiratory distress in all but one patient was seen as well. CONCLUSIONS: Administration of sodium bicarbonate in 17 children with LTA was associated with a significant decrease in Pco(2) and an improvement of respiratory distress. The possible benefits of sodium bicarbonate in LTA deserve further study in a controlled, prospective design. [ABSTRACT FROM AUTHOR]

Abstract Background Childhood overweight/obesity is a major public health problem worldwide which disproportionally affects specific ethnic groups. Little is known about whether such differences already exist at an early age and which factors contribute to these ethnic differences. Therefore, the present study assessed possible ethnic differences in overweight at age 2 years, and the potential explanatory role of prenatal factors, birth outcomes and postnatal factors. Methods Data were derived from a multi-ethnic cohort in the Netherlands (the ABCD study). Weight and height data of 3,156 singleton infants at age 2 years were used. Five ethnic populations were distinguished: Dutch native (n = 1,718), African descent (n = 238), Turkish (n = 162), Moroccan (n = 245) and other non-Dutch (n = 793). Overweight status was defined by the International Obesity Task Force guidelines. The explanatory role of prenatal factors, birth outcomes and postnatal factors in ethnic disparities in overweight (including obesity) was assessed by logistic regression analysis. Results Compared to the native Dutch (7.1%), prevalence of overweight was higher in the Turkish (19.8%) and Moroccan (16.7%) group, whereas the prevalence was not increased in the African descent (9.2%) and other non-Dutch (8.8%) group. Although maternal pre-pregnancy body mass index partly explained the ethnic differences, the odds ratio (OR) of being overweight remained higher in the Turkish (OR: 2.66; 95%CI: 1.56-4.53) and Moroccan (OR: 2.11; 95%CI: 1.31-3.38) groups after adjusting for prenatal factors. The remaining differences were largely accounted for by weight gain during the first 6 months of life (postnatal factor). Maternal height, birth weight and gender were independent predictors for overweight at age 2 years, but did not explain the ethnic differences. Conclusion Turkish and Moroccan children in the Netherlands have 2- to 3-fold higher odds for being overweight at age 2 years, which is largely attributed to maternal pre-pregnancy BMI and weight gain during the first 6 months of life. Further study on the underlying factors of this early weight gain is required to tackle ethnic differences in overweight among these children.

Study Objectives: Despite frequent sleep disruption in the paediatric intensive care unit (PICU), bedside sleep monitoring in real-time is currently not available. Supervised machine learning (ML) applied to electrocardiography (ECG) data may provide a solution, since cardiovascular dynamics are directly modulated by the autonomic nervous system (ANS) during sleep., Methods: Retrospective study using hospital-based polysomnography (PSG) recordings obtained in non-critically ill children between 2017 and 2021. Six age categories were defined: 6-12 months, 1-3 years, 3-5 years, 5-9 years, 9-13 years and 13-18 years. Features were derived in time, frequency and non-linear domain from pre-processed ECG data. Sleep classification models were developed for two, three, four and five state using logistic regression (LR), random forest (RF) and XGBoost (XGB) classifiers during five-fold nested cross-validation. Models were additionally validated across age categories., Results: A total of 90 non-critically ill children were included with a median (Q1, Q3) recording length of 549.0 (494.8, 601.3) minutes. The three models obtained AUROC 0.72 - 0.78 with minimal variation across classifiers and age categories. Balanced accuracies were 0.70 - 0.72, 0.59 - 0.61, 0.50 - 0.51 and 0.41 - 0.42 for two, three, four and five state. Generally, the XGB model obtained the highest balanced accuracy (p < 0.05), except for five state where LR excelled (p = 0.67)., Conclusions: ECG-based ML models are a promising and non-invasive method for automated sleep classification directly at the bedside of non-critically ill children aged 6 months to 18 years. Models obtained moderate-to-good performance for two and three state classification., (© 2024 American Academy of Sleep Medicine.)

Background: The implementation of the approved respiratory syncytial virus (RSV) preventive interventions in immunisation programmes is advancing rapidly. Insight into healthcare costs of RSV-related paediatric intensive care unit (PICU) admissions is lacking, but of great importance to evaluate the impact of implementation. Therefore, this study aimed to determine the total annual RSV-related paediatric intensive care healthcare costs in the Netherlands., Methods: A nationwide prospective, observational, multicenter study was performed from September 2021 until June 2023. The total annual RSV-related healthcare costs on PICUs in the Netherlands were calculated using RSV-related costs (subgroup I) and consequential costs (subgroup II and III). Subgroup I comprised all PICU admitted infants ≤12 months of age with laboratory-confirmed RSV infection. Subgroup II and III consisted of postponed elective PICU admissions and refused acute PICU admissions due to RSV-related lack of PICU capacity., Findings: A total of 424 infants with RSV-related PICU admission were included. Median age at PICU admission was 46 days (IQR 25-89). The median length of PICU admission was 5 days (IQR 3-8). The total RSV-related PICU costs are € 3,826,386 in 2021-2022, and € 3,183,888 in 2022-2023. Potential costs averted by RSV preventive interventions is € 1.9 to € 2.6 million depending on season, and the duration of protection., Interpretation: RSV-related PICU admissions cost €3.1 to €3.8 million in the Netherlands during one season. The introduction of new RSV preventive interventions into the Dutch immunisation programme will generate significant cost-savings on PICUs and decreases the admission burden of PICUs., Funding: None., Competing Interests: EP, CB, MH, MK, SM, AN, MR, RWA, JvW and GF have no competing interests to declare. LB has regular interaction with pharmaceutical and other industrial partners. He has not received personal fees or other personal benefits. UMCU has received major funding (>€100,000 per industrial partner) for investigator initiated studies from AstraZeneca, Sanofi, Janssen, Pfizer, MSD and MeMed Diagnostics. UMCU has received major funding from the Bill and Melinda Gates Foundation. UMCU has received major funding as part of the public private partnership IMI-funded RESCEU and PROMISE projects with partners GSK, Novavax, Janssen, AstraZeneca, Pfizer and Sanofi. UMCU has received major funding by Julius Clinical for participating in clinical studies sponsored by AstraZeneca, Merck and Pfizer. UMCU received minor funding (€1000–25,000 per industrial partner) for consultation, DSMB membership or invited lectures by Ablynx, Bavaria Nordic, GSK, Novavax, Pfizer, Moderna, Astrazeneca, MSD, Sanofi, Janssen. LB is the founding chairman of the ReSViNET Foundation. JGW has been an investigator for clinical trials sponsored by pharmaceutical companies including AstraZeneca, Merck, Pfizer, Sanofi, and Janssen and an investigator for clinical trials funded by IMI/Horizon2020 and ZonMw. All funds have been paid to the institution (UMCU). JGW participated in advisory boards of Janssen and Sanofi and was a speaker at a Sanofi sponsored symposium with fees paid to the institution (UMCU)., (© 2024 The Author(s).)

Background: The respiratory microbiome has been associated with the etiology and disease course of asthma., Objective: We sought to assess the nasopharyngeal microbiota in children with a severe asthma exacerbation and their associations with medication, air quality, and viral infection., Methods: A cross-sectional study was performed among children aged 2 to 18 years admitted to the medium care unit (MCU; n = 84) or intensive care unit (ICU; n = 78) with an asthma exacerbation. For case-control analyses, we matched all cases aged 2 to 6 years (n = 87) to controls in a 1:2 ratio. Controls were participants of either a prospective case-control study or a longitudinal birth cohort (n = 182). The nasopharyngeal microbiota was characterized by 16S-rRNA-gene sequencing., Results: Cases showed higher Shannon diversity index (ICU and MCU combined; P = .002) and a distinct microbial community composition when compared with controls (permutational multivariate ANOVA R 2  = 1.9%; P < .001). We observed significantly higher abundance of Staphylococcus and "oral" taxa, including Neisseria, Veillonella, and Streptococcus spp. and a lower abundance of Dolosigranulum pigrum, Corynebacterium, and Moraxella spp. (MaAsLin2; q < 0.25) in cases versus controls. Furthermore, Neisseria abundance was associated with more severe disease (ICU vs MCU MaAslin2, P = .03; q = 0.30). Neisseria spp. abundance was also related with fine particulate matter exposure, whereas Haemophilus and Streptococcus abundances were related with recent inhaled corticosteroid use. We observed no correlations with viral infection., Conclusions: Our results demonstrate that children admitted with asthma exacerbations harbor a microbiome characterized by overgrowth of Staphylococcus and "oral" microbes and an underrepresentation of beneficial niche-appropriate commensals. Several of these associations may be explained by (environmental or medical) exposures, although cause-consequence relationships remain unclear and require further investigations., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Objectives: Healthcare grapples with staff shortages and rising burnout rates for medical students, residents and specialists. To prioritise both their well-being and the delivery of high-quality patient care, it becomes imperative to deepen our understanding of physicians' developmental aims and needs. Our first aim is, therefore, to gain comprehensive insights into the specific developmental aims physicians prioritise by examining the coaching goals they set at the beginning of coaching. Since physicians face distinct roles as they advance in their careers, our second aim is to highlight similarities and differences in developmental aims and needs among individuals at various medical career stages., Design: We conducted a qualitative analysis of 2571 coaching goals. We performed an inductive thematic analysis to code one-half of coaching goals and a codebook thematic analysis for the other half. Our interpretation of the findings was grounded in a critical realist approach., Setting: Sixteen hospitals in the Netherlands., Participants: A total of 341 medical clerkship students, 336 medical residents, 122 early-career specialists, 82 mid-career specialists and 57 late-career specialists provided their coaching goals at the start of coaching., Results: The findings revealed that coachees commonly set goals about their career and future, current job and tasks, interpersonal work relations, self-insight and development, health and well-being, nonwork aspects and the coaching process. Furthermore, the findings illustrate how the diversity of coaching goals increases as physicians advance in their careers., Conclusions: Our findings underscore the significance of recognising distinct challenges at various career stages and the necessity for tailoring holistic support for physicians. This insight holds great relevance for healthcare organisations, enabling them to better align system interventions with physicians' needs and enhance support. Moreover, our classification of coaching goals serves as a valuable foundation for future research, facilitating a deeper exploration of how these goals influence coaching outcomes., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Introduction: Bleeding and thrombotic complications are common in extracorporeal membrane oxygenation (ECMO) patients and are associated with increased mortality and morbidity. The optimal anticoagulation monitoring protocol in these patients is unknown. This study aims to compare the incidence of thrombotic and hemorrhagic complications before and after a protocol change. In addition, the association between hemostatic complications, coagulation tests and risk factors is evaluated., Methods: This is a retrospective single center cohort study of adult ECMO patients. We collected demographics, ECMO parameters and coagulation test results. Outcomes of the aPTT guided and multimodal protocol, including aPTT, anti-Xa assay and rotational thromboelastometry were compared and the association between coagulation tests, risk factors and hemostatic complications was determined using a logistic regression analysis for repeated measurements., Results: In total, 250 patients were included, 138 in the aPTT protocol and 112 in the multimodal protocol. The incidence of thrombosis (aPTT: 14%; multimodal: 12%) and bleeding (aPTT: 36%; multimodal: 40%), did not significantly differ between protocols. In the aPTT guided protocol, the aPTT was associated with thrombosis (Odds Ratio [OR] 1.015; 95% confidence interval [CI] 1.004-1.027). In both protocols, surgical interventions were risk factors for bleeding and thrombotic complications (aPTT: OR 93.2, CI 39.9-217.6; multimodal OR 17.5, CI 6.5-46.9)., Discussion: The incidence of hemostatic complications was similar between both protocols and surgical interventions were a risk factor for hemostatic complications. Results from this study help to elucidate the role of coagulation tests and risk factors in predicting hemostatic complications in patients undergoing ECMO support., Competing Interests: Declaration of conflicting interestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Aim: Investigate long-term outcome in paediatric submersion-related cardiac arrests (CA)., Methods: Children (age one day-17 years) were included if admitted to the Erasmus MC Sophia Children's Hospital, after drowning with CA, between 2002 and 2019. Primary outcome was survival with favourable neurological outcome, defined as a Paediatric Cerebral Performance Category (PCPC) score of 1-3 at longest available follow-up. Secondary outcome were age-appropriate neuropsychological assessments at longest available follow-up., Results: Upon hospital admission, 99 children were included (median age at time of CA 3.2 years [IQR 2.0-5.9] and 65% males). Forty children died in-hospital (no return of circulation (45%) or withdrawal of life sustaining therapies (55%)) and 4 children deceased after hospital discharge due to complications following the drowning-incident. Among survivors, with a median follow-up of 2.3 years [IQR 0.2-5.5], 47 children had favourable neurological outcome (i.e. PCPC 1-3) and 8 children unfavourable (unfavourable outcome group total n = 52, i.e. PCPC 4-5 or deceased). Twenty-six (47%) children participated in a neuropsychological assessment (median follow-up 4.0 years [IQR 2.3-8.7]). Compared with normative test data, participants obtained worse general ( p  = 0.008) and performance ( p  = 0.003) intelligence scores, processing speed ( p  = 0.002) and visual motor integration scores ( p  = 0.0012)., Conclusions: Although overall outcome in survivors was favourable at longest available follow-up, significant deficits in neuropsychological assessments were found. This study underlines the need for a standardized long term follow-up program as standard of care in paediatric drowning with CA., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Author(s).)

Aims: Whether and when glomerular filtration rate (GFR) in preterms catches up with term peers is unknown. This study aims to develop a GFR maturation model for (pre)term-born individuals from birth to 18 years of age. Secondarily, the function is applied to data of different renally excreted drugs., Methods: We combined published inulin clearance values and serum creatinine (Scr) concentrations in (pre)term born individuals throughout childhood. Inulin clearance was assumed to be equal to GFR, and Scr to reflect creatinine synthesis rate/GFR. We developed a GFR function consisting of GFR birth (GFR at birth), and an Emax model dependent on PNA (with GFR max , PNA 50 (PNA at which half of GFR max is reached) and Hill coefficient). The final GFR model was applied to predict gentamicin, tobramycin and vancomycin concentrations., Result: In the GFR model, GFR birth varied with birthweight linearly while in the PNA-based Emax equation, GA was the best covariate for PNA 50 , and current weight for GFR max . The final model showed that for a child born at 26 weeks GA, absolute GFR is 18%, 63%, 80%, 92% and 96% of the GFR of a child born at 40 weeks GA at 1 month, 6 months, 1 year, 3 years and 12 years, respectively. PopPK models with the GFR maturation equations predicted concentrations of renally cleared antibiotics across (pre)term-born neonates until 18 years well., Conclusions: GFR of preterm individuals catches up with term peers at around three years of age, implying reduced dosages of renally cleared drugs should be considered below this age., (© 2024. The Author(s).)

Study Objectives: Although sleep is frequently disrupted in the pediatric intensive care unit, it is currently not possible to perform real-time sleep monitoring at the bedside. In this study, spectral band powers of electroencephalography data are used to derive a simple index for sleep classification., Methods: Retrospective study at Erasmus MC Sophia Children's Hospital, using hospital-based polysomnography recordings obtained in non-critically ill children between 2017 and 2021. Six age categories were defined: 6-12 months, 1-3 years, 3-5 years, 5-9 years, 9-13 years, and 13-18 years. Candidate index measures were derived by calculating spectral band powers in different frequent frequency bands of smoothed electroencephalography. With the best performing index, sleep classification models were developed for two, three, and four states via decision tree and five-fold nested cross-validation. Model performance was assessed across age categories and electroencephalography channels., Results: In total 90 patients with polysomnography were included, with a mean (standard deviation) recording length of 10.3 (1.1) hours. The best performance was obtained with the gamma to delta spectral power ratio of the F4-A1 and F3-A1 channels with smoothing. Balanced accuracy was 0.88, 0.74, and 0.57 for two-, three-, and four-state classification. Across age categories, balanced accuracy ranged between 0.83 and 0.92 and 0.72 and 0.77 for two- and three-state classification, respectively., Conclusions: We propose an interpretable and generalizable sleep index derived from single-channel electroencephalography for automated sleep monitoring at the bedside in non-critically ill children ages 6 months to 18 years, with good performance for two- and three-state classification., Citation: van Twist E, Hiemstra FW, Cramer ABG, et al. An electroencephalography-based sleep index and supervised machine learning as a suitable tool for automated sleep classification in children. J Clin Sleep Med . 2024;20(3):389-397., (© 2024 American Academy of Sleep Medicine.)

Household studies provide an efficient means to study transmission of infectious diseases, enabling estimation of susceptibility and infectivity by person-type. A main inclusion criterion in such studies is usually the presence of an infected person. This precludes estimation of the hazards of pathogen introduction into the household. Here we estimate age- and time-dependent household introduction hazards together with within household transmission rates using data from a prospective household-based study in the Netherlands. A total of 307 households containing 1,209 persons were included from August 2020 until March 2021. Follow-up of households took place between August 2020 and August 2021 with maximal follow-up per household mostly limited to 161 days. Almost 1 out of 5 households (59/307) had evidence of an introduction of SARS-CoV-2. We estimate introduction hazards and within-household transmission rates in our study population with penalized splines and stochastic epidemic models, respectively. The estimated hazard of introduction of SARS-CoV-2 in the households was lower for children (0-12 years) than for adults (relative hazard: 0.62; 95%CrI: 0.34-1.0). Estimated introduction hazards peaked in mid October 2020, mid December 2020, and mid April 2021, preceding peaks in hospital admissions by 1-2 weeks. Best fitting transmission models included increased infectivity of children relative to adults and adolescents, such that the estimated child-to-child transmission probability (0.62; 95%CrI: 0.40-0.81) was considerably higher than the adult-to-adult transmission probability (0.12; 95%CrI: 0.057-0.19). Scenario analyses indicate that vaccination of adults can strongly reduce household infection attack rates and that adding adolescent vaccination offers limited added benefit., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 van Boven et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)