Swiss Medical Weekly

IntroductionChildren represent a large and vulnerable patient group. However, the evidence-base for most paediatric diagnostic and therapeutic procedures remains limited or is often inferred from adults. There is urgency to improve paediatric health care provision based on real-world evidence generation. The digital transformation is a unique opportunity to shape a data-driven, agile, learning health care system and deliver more efficient and personalized care to children and their families. The goal of SwissPedHealth is to build a sustainable and scalable infrastructure to make routine clinical data from paediatric hospitals in Switzerland interoperable, standardized, quality-controlled, and ready for observational research, quality assurance, trials, and health-policy creation. This paper describes the design, aims, and current achievements of SwissPedHealth. Methods and analysisSwissPedHealth started in September 2022 as one of four National Data Streams co-funded by the Swiss Personalized Health Network (SPHN) and the Personalized Health and Related Technologies (PHRT). SwissPedHealth develops modular governance and regulatory strategies, and harnesses SPHN automatization procedures, in collaboration with clinical data warehouses, the Data Coordination Center, Biomedical Information Technology Network, and other SPHN institutions and funded projects. The SwissPedHealth consortium is led by a multi-site, multi-disciplinary Steering Committee incorporating patient and family representatives. The data stream contains work packages focusing on: 1) governance and implementation of standardized data collection, 2) nested projects to test the feasibility of the data stream, 3) a lighthouse project that enriches the data stream by integrating multi-omics data, aiming to improve diagnoses of rare diseases, and 4) engagement with families through patient and public involvement activities and bioethics interviews. Ethics and disseminationThe health database regulation of SwissPedHealth was approved by the ethics committee (AO_2022-00018). Research findings will be disseminated through national and international conferences, publications in peer-reviewed journals and in lay language via online media and podcasts. ARTICLE SUMMARY The paediatric national data stream SwissPedHealth focuses on routine clinical data from children at Swiss University Childrens Hospitals, spans disciplines and is built in a scalable and modular way in terms of governance, data infrastructure, and patient and public involvement, to enable a gradual increase in coverage of the Swiss child population. SwissPedHealth strives to increase readiness for quality improvement, research, and personalized paediatric health care. SwissPedHealths infrastructure aligns with the national frameworks, safeguarding data security and adhering to a standard interoperability framework based on the Resource Description Framework (RDF). SwissPedHealth seeks to explore integration of data from external sources such as federal statistics, cohorts, and registries, which have their own governance and data formats. * SwissPedHealth investigates the use of multi-omics workflows to improve diagnosis of rare diseases in children with life-threatening phenotypes

ObjectivesTo longitudinally assess severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) seroprevalence and clustering of seropositive children within school classes in March-April 2021 compared to June-July and October-November 2020. To examine the evolution of symptoms and the extent of under-detection of SARS-CoV-2 in children. DesignProspective cohort study of randomly selected schools and classes. SettingSchools remained open for physical attendance in Switzerland from May 2020 to the end of 2020/2021 school year. Lower school level (age range 7-10 years) and middle school level (8-13 years) children in primary schools, and upper school level (12-17 years) children in secondary schools were invited for SARS-CoV-2 serological testing in the Ciao Corona study in the canton of Zurich, Switzerland. Three testing rounds were completed in June-July 2020 (T1; after the first wave of SARS-CoV-2 infections), October-November 2020 (T2; during the peak of the second wave), and March-April 2021 (T3; after the second wave and with SARS-CoV-2 variants of concern becoming dominant). Parents completed questionnaires on sociodemographic information and symptoms. Participants2487 children (median age 12 years, age range 7-17 years) recruited from 275 classes in 55 schools participated in the testing in March-April 2021; total of 2974 children participated in at least one of the 3 testing rounds. Main outcome measuresSARS-CoV-2 serology results; clustering of seropositive children within classes; reported symptoms. ResultsThe proportion of children who were SARS-CoV-2 seropositive increased from 1.5% (95% credible interval (CrI) 0.6% to 2.6%) in June-July 2020, to 6.6% (95% CrI 4.0% to 8.9%) in October-November, and to 16.4% (95% CrI 12.1% to 19.5%) in March-April 2021. By March-April 2021, children in upper school level (12.4%; 95% CrI 7.3% to 16.7%) were less likely to be seropositive than those in middle (19.5%; 95% CrI 14.2% to 24.4%) or lower school levels (16.0%; 95% CrI 11.0% to 20.4%). Children in the upper school level had a 5.1% (95% CI -9.4% to -0.7%) lower than expected seroprevalence by March-April 2021 than those in middle school level, based on difference-in-differences analysis. The ratio of PCR-diagnosed to all seropositive children changed from 1 to 21.7 (by June-July 2020) to 1 to 3.5 (by March-April 2021). Symptoms were reported by 37% of newly seropositive and 16% seronegative children. Potential clusters of 3 or more newly seropositive children were detected in 24 of 119 (20%) classes with a high participation rate, from which a median of 17 clusters could be expected due to random distribution of seropositive children within the classes. Clustering was lowest in middle and upper school levels. Retention rate in the cohort was high (84% of T1 participants attended T3). Among participants, supporting society and research were reported more commonly for participation than personal reasons. Fear of blood sampling was the most frequently reported reason for non-participation, reported for 64% of children. ConclusionsBy March-April 2021, 16.4% of children and adolescents were seropositive in the canton of Zurich, Switzerland. The majority of clusters of SARS-CoV-2 seropositive children in school classes could be explained by community rather than intra-class transmission of infections. Seroprevalence and clustering was lowest in upper school levels during all timepoints. Trial registrationClinicalTrials.gov NCT04448717. What is already known on the topicO_LITransmission of SARS-CoV-2 in school setting largely followed community transmission in 2020. C_LIO_LIWith implemented preventive measures, secondary attack rates were low and clustering of SARS-CoV-2 infections within classes and schools (outbreaks) were observed rarely. C_LI What this study addsO_LIWith high community incidence and new variants of SARS-CoV-2, seroprevalence increased in school children between October 2020 - March 2021 in the canton of Zurich in Switzerland, and was higher in lower school levels. C_LIO_LIMost of the potential clusters of children who tested seropositive within classes could be explained by community rather than intra-class transmission of SARS-CoV-2, especially in middle and upper school levels. C_LIO_LIMore children who tested seropositive in March-April 2021 were diagnosed and reported symptoms potentially related to SARS-CoV-2 infection more frequently than those who tested seropositive in June-July or October-November 2020. C_LIO_LIThe most frequent reason for non-participation was fear of blood sampling (62% of children). C_LI

BackgroundOur study aims to enhance future pandemic preparedness by integrating lessons from historical pandemics, focusing on the multidimensional analysis of past outbreaks. It addresses the gap in existing modelling studies by combining various pandemic parameters in a comprehensive setting. Using Zurich as a case study, we seek a deeper understanding of pandemic dynamics to inform future scenarios. Data and methodsWe use newly digitized weekly aggregated epidemic/pandemic time series (incidence, hospitalisations, mortality and sickness absences from work) to re-model the 1918-1920 pandemic in Zurich and investigate how different parameters correspond, how transmissibility changed during the different waves, and how public health interventions were associated with changes in these pandemic parameters. ResultsIn general, the various time series show a good temporal correspondence, but differences in their expression can also be observed. The first wave in the summer of 1918 did lead to illness, absence from work and hospitalisations, but to a lesser extent to increased mortality. In contrast, the second, longest and strongest wave in the autumn/winter of 1918 also led to greatly increased (excess) mortality in addition to the burden of illness. The later wave in the first months of 1920 was again associated with an increase in all pandemic parameters. Furthermore, we can see that public health measures such as bans on gatherings and school closures were associated with a decrease in the course of the pandemic, while the lifting or non-compliance with these measures was associated with an increase of reported cases. DiscussionOur study emphasizes the need to analyse a pandemics disease burden comprehensively, beyond mortality. It highlights the importance of considering incidence, hospitalizations, and work absences as distinct but related aspects of disease impact. This approach reveals the nuanced dynamics of a pandemic, especially crucial during multi-wave outbreaks.

AIMIn late February and early March 2020, Switzerland experienced rapid growth of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections with 30,243 confirmed cases and 1,860 deaths as of 10 May 2020. The sequential introduction of non-pharmaceutical interventions (NPIs) resulted in successful containment of the epidemic. A better understanding of how the timing of implementing NPIs influences the dynamics and outcome of SARS-CoV-2 epidemics will be crucial for the management of a potential resurgence in Switzerland. METHODSWe developed a dynamic transmission model that describes infection, hospitalization, recovery and death due to SARS-CoV-2 in Switzerland. Using a maximum likelihood framework, we fitted the model to aggregated daily numbers of hospitalized patients, ICU occupancy and death from 25 February to 10 May 2020. We estimated critical parameters of SARS-CoV-2 transmission in Switzerland and explored counterfactual scenarios of an earlier and later implementation of NPIs. RESULTSWe estimated the basic reproduction number R0 = 2.61 (95% compatibility interval, CI: 2.51-2.71) during the early exponential phase of the SARS-CoV-2 epidemic in Switzerland. After the implementation of NPIs, the effective reproduction number approached Re = 0.64 (95% CI: 0.61-0.66). Based on the observed doubling times of the epidemic before and after the implementation of NPIs, we estimated that one week of early exponential spread required 3.1 weeks (95% CI: 2.8-3.3 weeks) of lockdown to reduce the number of infections to the same level. Introducing the same sequence of NPIs one week earlier or later would have resulted in substantially lower (399, 95% prediction interval, PI: 347-458) and higher (8,683, 95% PI: 8,038-9,453) numbers of deaths, respectively. CONCLUSIONSThe introduction of NPIs in March 2020 prevented thousands of SARS-CoV-2-related deaths in Switzerland. Early implementation of NPIs during SARS-CoV-2 outbreaks can reduce the number of deaths and the necessary duration of strict control measures considerably.

This study shows that the quality of the morbidity data is sufficient to allow for meaningful analyses of spatiotemporal dynamics and provides a significant contribution to understanding the 1918-1920 influenza pandemic in Switzerland by complementing existing mortality- focused research with a morbidity perspective. Previous studies have examined the spatial patterns of mortality during the 1918-1920 influenza pandemic and associated explanatory factors. However, while mortality reflects the severity of a pandemic, a full understanding requires analysis of both morbidity and mortality. For the first time, this study systematically analysed district-level morbidity data for all of Switzerland and their associations with several ecological determinants. The spatial pattern of morbidity with the spatial pattern of mortality were also compared to investigate potential differences. Spatial clustering was assessed using the Getis-Ord Gi* statistic, and geographically weighted regression was employed to evaluate local relationships between incidence and ecological variables. Across all waves, higher incidence rates were positively associated with population density, GDP per capita, the share of industry, and the number of private physicians per km{superscript 2}. Conversely, GDP per capita and industrial activity were associated with lower mortality, while a higher proportion of men in a district correlated with lower incidence and higher mortality. The share of individuals aged 20- 39 years was associated with both higher incidence and higher mortality. These findings highlight that those factors shaping morbidity patterns can differ from those influencing mortality, emphasizing the importance of examining both dimensions for a comprehensive understanding of pandemic dynamics.

Recent studies assessing COVID-19 vaccine efficacy at the population level found counterintuitive results, such as positive associations between vaccination and infections or deaths. These ecological studies have limitations, including too short observation periods, focusing on infections, and not controlling for age groups and dominant variants. The current study addresses these limitations by investigating the relations between vaccination and COVID-19 cases, hospitalizations, and deaths over a longer period (9[1/2] months) while also considering age groups (from 10 to 80+ years old) and variants (Alpha and Delta), utilizing data from Switzerland. Results suggest that vaccination is negatively related to cases overall and in all cantons of Switzerland, and that vaccination is negatively related to hospitalizations and deaths from 50 years old. Furthermore, vaccination is a significant predictor of cases, hospitalizations, and deaths while holding the effects of age and dominant variant constant.

BackgroundIn late 2022, a surge of severe bacterial infections caused by S. pyogenes was reported in several European countries, including Germany. This study assessed disease burden and severity of hospitalizations for community-acquired bacterial infections with S. pyogenes, S. pneumoniae, N. meningitidis, and H. influenzae among children in North Rhine-Westphalia (NRW), Germany, during the last quarter of 2022 compared to long-term incidences. MethodsHospital cases due to bacterial infections between October and December 2022 were collected from 59/62 (95 %) childrens hospitals in NRW and combined with surveillance data (2016 - 2023) from the national reference laboratories for streptococci, N. meningitidis, and H. influenzae. Total cases in NRW and incidence rates from January 2016 to March 2023 were estimated by capture-recapture analyses. Expected annual deaths from the studied pathogens were calculated from national death cause statistics. ResultsBetween October and December 2022, 153 cases with high overall disease severity were reported with pneumonia being most common (59 %, n = 91). Incidence rates of bacterial infections declined at the beginning of the COVID-19 pandemic. In late 2022 and early 2023 a massive surge to levels unprecedented since 2016 was observed, mainly driven by S. pyogenes and S. pneumoniae. Observed deaths during the study period exceeded the expected number for the entire year in NRW by far (7 vs. 0.9). DiscussionThe unprecedented peak of bacterial infections in late 2022 and early 2023 was caused by various mechanisms intertwined that require close surveillance and improved precautionary measures for future outbreaks.

BackgroundMask wearing contributes to the reduction of transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). In Switzerland, compulsory use of masks was introduced in indoor public spaces and later in schools. In the canton of Zurich, masks were introduced for secondary school children (grades 7-9) from November 2020, and for primary school children (grades 4-6) from February 2021- along with other protective measures against SARS-CoV-2. This study explored perceptions towards the usefulness of masks in school and public in a cohort of children and adolescents in the canton of Zurich, Switzerland, in January - May 2021. MethodsSchool children aged 10 to 17 years enrolled in Ciao Corona, a prospective school-based cohort study, responded to nested online surveys between January 12 to March 24 2021 (Q1) and March 10 to May 16 2021 (Q2). Secondary school children were surveyed at Q1 and Q2, and primary school children at Q2 only. Surveys for parents and their children included questions on childrens perception of the usefulness of masks and mask wearing behavior. Associations between perceived usefulness of masks and childs school level, gender, and parents educational attainment were analyzed with Pearsons and McNemars chi-squared tests. Free-text comments provided by children were classified into categories of expressed attitude towards mask wearing. Results595 (54% girls) and 1118 (52% girls) school children responded to online questionnaires at Q1 and Q2, respectively. More than half of school children perceived masks to be useful at school (Q1:60% and Q2:57%) and in public (Q1:69% and Q2:60%). Girls perceived masks as useful more often than boys (at Q2 at school: 61% versus 53%, in public: 64% versus 57%), and children of parents with high educational attainment more often than those of parents with lower educational attainment (at Q2 at school: 61% versus 49%, in public: 63% versus 54%). There were no differences in the perceived usefulness of masks among children in primary versus secondary school. At Q1 and Q2 each, about 20% of children provided individual statements about masks, of which 36% at Q1 and 16% at Q2 reported side-effects and discomfort such as skin irritations, headache or difficulties breathing during physical education. ConclusionApproximately 60% of school children perceived masks at school and in public places as useful. A small but non-negligible proportion of children reported discomfort and side-effects that should be considered to ensure high adherence to mask wearing among school children. Trial registrationClinicalTrials.gov NCT04448717 https://clinicaltrials.gov/ct2/show/NCT04448717 CONTRIBUTION TO THE FIELD STATEMENTWorldwide about 150 countries fully closed their schools at some point during the coronavirus pandemic, while other countries - such as Switzerland - kept schools open almost all the time. However, among other protective measures, children in secondary school (aged approximately 14-16 years) had to wear masks since November 2020, and older children in primary school (aged 11-13 years) - since February 2021. As part of the large study Ciao Corona based in schools in Switzerland, we wanted to learn how children perceive the usefulness of masks in school and public. Children and their parents completed questionnaires in January-March (595 secondary school children) and March-May 2021 (1118 secondary and primary school children). We found that about 60% of children perceived masks to be useful at school and in public. Girls perceived masks as useful more often than boys, and children of parents with university or college education more often than those of parents with lower education. About 7- 9% of children reported side-effects and discomfort such as skin irritations, headache or difficulties breathing during physical education. Although side-effects were not frequently reported, they should be considered to ensure high adherence to mask wearing among school children.

Universal masking the health care setting and in the community to contain the spread of SARS-CoV-2 has been recently recommended by the WHO, but supporting data are rare. The City of Jena was the first community in Germany to issue an order on mandatory public masking. Here, we report the development of the number of novel infections in our hospital and in the city of Jena after implementation of universal masking in our hospital and the city.

IntroductionAs the role of school-aged children was unclear at the onset of the COVID-19 pandemic, public health authorities recommended to implement infection prevention and control (IPC) measures in school settings. Few studies evaluated the implementation of these measures and their effect on SARS-CoV-2 infection rates among pupils and staff. AimTo describe the implementation of IPC measures in Belgian primary and secondary schools and assess its relation to the prevalence of anti-SARS-CoV-2 antibodies among pupils and staff. MethodsWe conducted a prospective cohort study in a representative sample of primary and secondary schools in Belgium. Implementation of IPC measures in schools was assessed using an online questionnaire. Saliva samples were collected from pupils and staff to determine the SARS-CoV-2 seroprevalence. ResultsA variety of IPC measures (ventilation, hygiene and physical distancing) was implemented by more than 60% of primary and secondary schools with most attention for hygiene measures. Almost no differences in implementation coverage were observed between primary and secondary schools or the Dutch and French language network. Poor implementation of IPC measures was associated with an increased anti-SARS-CoV-2 antibody prevalence among pupils from 8.6% (95% CI: 4.5 - 16.6) to 16.7% (95% CI: 10.2 - 27.4) and staff from 11.5% (95% CI: 8.1 - 16.4) to 17.6% (95% CI: 11.5 - 27.0). This association was statistically significant for all IPC measures and pupils and staff combined. ConclusionBelgian schools were relatively compliant with recommended IPC measures at the school level. Poor implementation of IPC measures was associated with higher SARS-CoV-2 seroprevalence among pupils and staff. Trial registration numberTrial registration number: NCT04613817

BackgroundIn 2018, a hospital-based surveillance system for influenza (CH-SUR) was established in six tertiary care hospitals in Switzerland. From March 2020 onwards, this surveillance system was expanded to include more institutions, as well as COVID-19. AimTo quantitatively evaluate the timeliness and completeness of CH-SUR data and to qualitatively assess stakeholder perceptions of the importance, reliability and adaptability of the surveillance system. MethodsAll patients admitted to one of the participating centres for more than 24 hours and who had a laboratory-confirmed influenza virus or SARS-CoV-2 infection were included in CH-SUR. For all cases, we evaluated the timeliness and completeness of reporting to CH-SUR. A qualitative survey among CH-SUR stakeholders assessed perceived importance, understanding, reliability and adaptability of CH-SUR. ResultsUp to 20 centres participated in CH-SUR. Between December 2018 and October 2023, 7,375 cases of influenza were reported and between March 2020 and October 2023, 49,235 cases of COVID-19 were reported to CH-SUR. During the COVID-19 pandemic, time to data entry and completeness improved over time; the median delay of data entry in CH-SUR was 5 days (IQR=2-23) for COVID-19 and 4 days (IQR=2-15) for influenza during the period 2018-2023. The completeness of variables was high (99.4%), with the exception of COVID-19 or annual influenza vaccination status (respectively 15% and 72% of "Unknown" responses). Stakeholders perceived the system as important, relevant, understandable and adaptable. ConclusionCH-SUR has provided critical epidemiological and clinical information on hospitalised influenza and COVID-19 cases across Switzerland during the pandemic. Our evaluation highlighted the importance and relevance of this system among CH-SUR stakeholders, as well as its importance for preparedness and response to future infectious disease outbreaks.

As many countries plan to lift lockdown measures aimed at suppression of COVID-19, data from early regional epidemics in Italy were analysed to ascertain the effectiveness of the timing of preventative measures. The cumulative caseload data were extracted from regional epidemics in Italy. Epidemic features in regions where lockdown was applied early were compared to those where lockdown was applied later for statistical differences. There were statistically significant differences in the timing of the peak, the cumulative incidence at peak and the case/km2 at peak between regions where the lockdown had been applied early and those where it was applied late. The peak occurred 7 days earlier with four times less cases/km2 in regions where the lockdown was applied within 10 days of the start of the epidemic. Cumulative caseloads, cases/km2 and/or the number of days into an epidemic can be used to plan future localised suppression measures as part of a national post-lockdown policy. There were 350 (95% confidence interval (CI) 203) cumulative cases and 2.4 (CI 1.1) cases/km2 on day 8 of the regional epidemics.

ObjectiveTo characterize the clinical features of children and adolescents hospitalized with SARS-CoV-2 infections and to explore predictors for disease severity. DesignNationwide prospective observational cohort study. SettingData collected from 169 out of 351 childrens hospitals in Germany between March 18, 2020 and April 30, 2021 and comparison with the Statutory Notification System. Participants1,501 children and adolescents up to 19 years of age with laboratory confirmed SARS-CoV-2 infections who were admitted to childrens hospitals and subsequently reported to the COVID-19 registry of the German Pediatric Infectious Disease Society (DGPI). Main outcome measuresAdmission to intensive care, in-hospital. ResultsAs compared to the information in the statutory notification system, up to 30% of all children and adolescents hospitalized in Germany during the study period were reported to the DGPI registry. Median age was three years (IQR, 0-12), with 36% of reported cases being infants. Although roughly half of patients in the registry were not admitted to the hospital due to their SARS-CoV-2 infection, 72% showed infection-related symptoms during hospitalization. Preexisting comorbidities were present in 28%, most commonly respiratory disorders, followed by neurological, neuromuscular, and cardiovascular diseases. Median length of hospitalization was five days (IQR 3-10). Only 20% of patients received a SARS-CoV-2-related therapy. Infants were less likely to require therapy as compared to older children. Overall, 111 children and adolescents were admitted to intensive care units (ICU). In a fully adjusted model, patient age, trisomy 21, coinfections and primary immunodeficiencies (PID) were significantly associated with intensive care treatment. In a bivariate analysis, pulmonary hypertension, cyanotic heart disease, status post (s/p) cardiac surgery, fatty liver disease, epilepsy and neuromuscular impairment were statistically significant risk factors for ICU admission. ConclusionOverall, a small proportion of children and adolescents was hospitalized in Germany during the first year of the pandemic. The majority of patients within our registry was not admitted due to COVID-19 suggesting an overestimation of the disease burden even in hospitalized children. Nevertheless, a large proportion of children and adolescents with confirmed COVID-19 reported in Germany could be captured. This allowed for detailed assessment of overall disease severity and underlying risk factors in our cohort. The main risk factors for COVID-19 disease associated intensive care treatment were older patient age, trisomy 21, PIDs and coinfection at the time of hospitalization. Trial registrationRegistry of hospitalized pediatric patients with SARS-CoV-2 infection (COVID-19), DRKS00021506

BackgroundIn Germany, diagnosis-based hospital surveillance of severe acute respiratory infections (SARI) incidence is operated weekly. However, diagnosis data from the most recent weeks is provisional and may be subject to systematic changes that we wish to account for to achieve a timely assessment of SARI trends. MethodsWe developed a novel nowcasting method based on (i) the already available data for the current week and (ii) historic changes in the data in weeks following initial reporting. The available weekly data were rescaled using multiplicative factors based on the historic patterns, to obtain the expected final incidence. We fit a parametric Beta distribution for observed upward changes in reported incidence, and a mixture distribution in case of the existence of downward changes, e.g., due to later corrections in diagnoses. We evaluated the model performance for the respiratory winter season 2024/2025. ResultsThe average weekly SARI incidence upon initial estimation in the first week after hospitalisation was 79.4% (median) of the incidence five weeks after hospitalisation, which was considered final. It increased to 95.1% in the second week after hospitalisation. The nowcast predictions matched the final incidences well and were able to indicate trends in real-time. Prediction intervals were well-calibrated and nowcasting can be performed in subgroups given sufficient case numbers. ConclusionsThe SARI surveillance in Germany achieved a high completeness already in the initial weeks after hospitalisation. The newly-developed nowcasting method yielded robust results with reliable uncertainty quantification. In combination, this facilitates a close to real-time assessment of SARI hospitalisation incidence in Germany.

We develop a two strain, age-structured, compartmental model to assess the spreading potential of the B.1.1.7 variant across several European metropolitan areas and countries. The model accounts for B.1.1.7 introductions from the UK and different locations, as well as local mitigation policies in the time period 2020/09 - 2021/02. In the case of an increase of transmissibility of 50%, the B.1.1.7 variant has the potential to become dominant in all investigated areas by the end of March 2021.

BackgroundDuring the Covid19 pandemic, school closure has been mandated in analogy to its known effect against influenza, but it is unclear whether schools are early amplifiers of Covid19 cases. MethodsWe performed a cross-sectional and prospective cohort study in Italy. We used databases from the Italian Ministry of Education containing the number of new positive SARS-CoV-2 cases per school from September 20 to November 8, 2020 to calculate incidence among students and staff. We calculated incidence across each age group using databases from the Veneto Region system of SARS-CoV-2 cases notification in the period August 26- November 24, 2020. We used a database from the Veneto Region system of SARS-CoV-2 secondary cases tracing in Verona province schools to estimate number of tests, the frequency of secondary infections at school by type of index case and the ratio positive cases/ number of tests per school institute using an adjusted multivariable generalized linear regression model. We estimated the reproduction number Rt at the regional level from the Italian Civil Protection of regional SARS-CoV-2 cases notification database in the period 6 August-2 December 2020. FindingsFrom September 12 to November 7 2020, SARS-CoV-2 incidence among students was lower than that in the general population of all but two Italian regions. Secondary infections were <1%, and clusters of >2 secondary cases per school were 5-7% in a representative November week. Incidence among teachers was greater than in the general population. However, when compared with incidence among similar age groups, the difference was not significant (P=0.23). Secondary infections among teachers were more frequent when the index case was a teacher than a student (38% vs. 11%, P=0.007). From August 28 to October 25 in Veneto where school reopened on September 14, the growth of SARS-CoV- 2 incidence was lower in school age individuals, maximal in 20-29 and 45-49 years old individuals. The delay between the different school opening dates in the different Italian regions and the increase in the regional Covid19 reproduction number Rt was not uniform. Reciprocally, school closures in two regions where they were implemented before other measures did not affect the rate of Rt decline. InterpretationOur analysis does not support a role for school opening as a driver of the second wave of SARS-CoV-2 epidemics in Italy, a large European country with high SARS-CoV-2 incidence. Research in contextO_ST_ABSEvidence before this studyC_ST_ABSThe role of schools and at large of children as amplifiers of the Covid19 pandemics is debated. Despite biological and epidemiological evidence that children play a marginal role in Sars-CoV-2 spread, policies of school closures have been predicated, mostly based on the temporal coincidence between school reopening in certain countries and Covid19 outbreaks. Whether schools contributed to the so called "second wave" of Covid19 is uncertain. Italys regionalized calendar of school reopening and databases of positivity at school allows to estimate the impact of schools on the increase of Sars-CoV-2 that occurred in autumn 2020. Added value of this studyWe found that incidence among students is lower than in the general population and that whereas incidence among teachers appears higher than that in the general population, it is comparable to that among individuals of the same age bracket. Moreover, secondary infections at school are rare and clusters even less common. The index case of a secondary teacher case is more frequently a teacher than a student. In Veneto, during the first phase of the second wave incidence among school age individuals was low as opposed to the sustained incidence among individuals of 45-49 years. Finally, the time lag between school opening and Rt increase was not uniform across different Italian regions with different school opening dates, with lag times shorter in regions where schools opened later. Implications of the available evidenceThese findings contribute to indicate that Covid19 infections rarely occur at school and that transmission from students to teachers is very rare. Moreover, they fail to support a role for school age individuals and school openings as a driver of the Covid19 second wave. Overall, our findings could help inform policy initiatives of school openings during the current Covid19 pandemic.

AimsNationwide registration of childhood cancers in Switzerland began in 1976. With the implementation of the Federal Law on Cancer Registration in 2020, cancer registration became compulsory, and methods were standardized nationwide across childhood and adult cancers. This paper describes the objectives and methods of the Childhood Cancer Registry (ChCR) as of 2025 and presents recent data on incidence, mortality and survival of childhood and adolescent cancers in Switzerland. MethodsThe ChCR records all primary cancers diagnosed in children and adolescents aged 0-19 years who live in Switzerland. Case reporting is mandatory for physicians, hospitals, and pathology laboratories. Eligible diagnoses include all malignant tumors, tumors of uncertain/unknown behavior, benign central nervous system tumors, histiocytosis, and selected other conditions. Cases are coded primarily according to ICD-10, ICD-O, the International Classification of Childhood Cancer (ICCC), and the Toronto Childhood Cancer Staging Guidelines. The registry collaborates closely with the Swiss Paediatric Oncology Group (SPOG), Cantonal Cancer Registries (CCRs), the National Agency for Cancer Registration (NACR), and the Federal Statistical Office (FSO). We calculated incidence and mortality rates for patients diagnosed between 2014 and 2023 using FSO population statistics and estimated 1-, 5- and 10-year observed survival using the Kaplan-Meier method with the period approach. ResultsFrom 1976 to 2023, 12,665 primary cancers diagnosed in individuals aged 0-19 years were registered. Between 2014 and 2023, 2,441 new cases were diagnosed among children (0-14 years) and an estimated 1,214 among adolescents (15-19 years), adjusting for incomplete regional coverage in adolescents before 2020. In children, the most frequent diagnostic groups were CNS tumors (653, 27%), leukemias (641, 26%) and lymphomas (275, 11%), followed by neuroblastoma, soft tissue sarcomas and other carcinomas and melanomas (all 6%), kidney tumors (5%) and bone tumors (4%). In adolescents, the most common diagnoses were lymphomas (287, 24%), carcinomas and melanomas (277, 23%), and CNS tumors (213, 18%), followed by leukemias (12%) and germ cell tumors (10%). Age-standardized annual incidence per million (standardized to the European Standard Population 2013) was 189 (95% CI 182- 197) in children aged 0-14, and 282 (95% CI 265-299) in those aged 15-19. Overall, five-year survival was 89% for children and 90% for adolescents, with variation across ICCC-3 diagnostic groups. ConclusionsWith mandatory reporting and strong collaboration among national stakeholders, the ChCR has evolved into a comprehensive and reliable data source. Its high completeness and long-term follow-up make it a critical resource for epidemiological and clinical research on childhood and adolescent cancers in Switzerland.

BACKGROUND: We used anthropometric data from electronic health records (EHRs) of Swiss childrens hospitals to evaluate growth references and estimate centile curves. METHODS: We received EHRs extracted from seven Swiss childrens hospitals and analysed two samples: all children with a height, weight, body mass index (BMI), or head circumference recording, and a subsample restricted to children without diseases potentially affecting growth, weighted to represent the general population. We calculated mean z-scores based on the World Health Organization growth references adopted for Switzerland in 2011 (CH-WHO 2011) and current Swiss growth references (Swiss 2026). We estimated sex-specific centile curves in the subsample using generalised additive models for location, scale, and shape. RESULTS: We included 213,868 children with height, 448,002 with weight, 209,244 with BMI, and 67,397 with head circumference recordings. Mean z-scores in the all children sample were (CH-WHO 2011; Swiss 2026): height (0.10; -0.19), weight (0.16; -0.09), BMI (0.04; -0.07), head circumference (-0.28, -0.28); and in the subsample: height (0.34; 0.00), weight (0.27; 0.01), BMI (0.18; 0.05), and head circumference (0.04; 0.01). The 50th height, weight, BMI, and head circumference centiles of girls and boys in the subsample closely followed those of Swiss 2026, with slightly wider 3rd and 97th centiles in infancy and adolescence. CONCLUSION: Height, weight, BMI, and head circumference centiles aligned well with the Swiss 2026 growth references in Switzerland, demonstrating that hospital EHRs could contribute to future growth references.

ObjectivesTo describe the development and usage of coronabambini.ch as an example of a pediatric electronic public health application and to explore its potential and limitations in providing information on disease epidemiology and public health policy implementation. DesignWe developed and maintained a non-commercial online decision support tool, coronabambini.ch, to translate the Swiss FOPH pediatric (age 0-18 years) COVID-19 guidelines around testing and school/daycare attendance for caregivers, teachers, and healthcare personnel. We analyzed the online decision tool as well as a voluntary follow-up survey from October 2020 to September 2021 to explore its potential as a surveillance tool for public health policy and epidemiology. Participants68269 users accessed and 52726 filled out the complete online decision tool. 3% (1399/52726) filled out a voluntary follow-up. 92% (18797/20330) of users were parents. ResultsCertain dynamics of the pandemic and changes in testing strategies were reflected in the data captured by coronabambini.ch: e.g. in terms of disease epidemiology, gastrointestinal symptoms were reported more frequently in younger age-groups (13% (3308/26180) in children 0-5 years versus 9% (3934/42089) in children [&ge;]6 years, [X]2=184, P=<.001). As a reflection of public health policy, the proportion of users consulting the tool for a positive contact without symptoms in children 6-12 years increased from 4% (1415/32215) to 6% (636/9872) after the FOPH loosened testing criteria in this age-group, [X]2=69, P=<.001. Adherence to the recommendation was generally high (84% (1131/1352)) but differed by the type of recommendation: 89% (344/385) for "stay at home and observe", 75% (232/310) for "school attendance". ConclusionsUsage of coronabambini.ch was generally high in areas where it was developed and promoted. Certain patterns in epidemiology and adherence to public health policy could be depicted but selection bias was difficult to measure showing the potential and challenges of digital decision support as public health tools. Strengths and limitations of this studyO_LIWe developed and maintained a non-commercial online decision support tool, coronabambini.ch, based on the Swiss Federal Office of Public Health (FOPH) pediatric COVID-19 guidelines around testing and school/daycare attendance. C_LIO_LIWe performed a descriptive analysis of the usage data from the tool between October 2020 to September 2021 to explore its potential as a surveillance tool for public health policy and epidemiology. C_LIO_LIA follow-up survey measured comprehensibility and adherence of the online decision tool. C_LIO_LIThe types of selection biases of the data were difficult to assess within this voluntary online survey system. C_LIO_LIResponse rate of the follow-up survey was low and participants with high education and high health literacy were overrepresented. C_LI

BackgroundContact tracing has been one of the central non-pharmaceutical interventions implemented worldwide to try to control the spread of Sars-CoV-2, but its effectiveness strongly depends on its ability to detect contacts. MethodsWe analysed 166892 concomitant infections occurring at the same address from June 2020 until February 2022 using an extensive operational database of SARS-CoV-2 tests in Geneva and used permutations statistics to compare the total number of secondary infections occurring at the address with those reported through contact tracing. ResultsManual contact tracing captured on average 41% of the secondary infections, with variation in time from 23% during epidemic peaks to 60% during low epidemic activity. People living in wealthy neighbourhoods were less likely to report contacts (adjusted odds ratio (aOR): 1.6). People living in buildings, compared to people living in single house, were also less likely to report contacts than those living in houses, with an aOR of 1.1 to 3.1 depending on the variant, the size of the building and the presence of shops. This under-reporting of contacts in buildings decreased during periods of mandatory face masking and restriction of private gathering. ConclusionsContact tracing alone does not detect enough secondary infections to efficiently reduce the propagation of Sars-CoV-2. Public messages and outreach campaigns targeting specific populations, such as those in affluent areas, could enhance coverage. Additionally, measures like wearing face masks, improving ventilation, and implementing gathering restrictions should also be considered to reduce the number of infections occurring during interactions that may not be perceived as high risk.