Swiss Paediatric Surveillance Unit Research Articles

Cardiac involvement in children with paediatric multisystem inflammatory syndrome temporally associated with SARS-CoV-2 (PIMS-TS): data from a prospective nationwide surveillance study.

Paediatric inflammatory multisystem syndrome temporally associated with SARS-CoV-2 (PIMS-TS) may occur 4 to 8 weeks after SARS-CoV-2 infection. The acute presentation of PIMS-TS has been well described, but data on longer-term outcomes, particularly cardiac, is scarce. This prospective nationwide surveillance study included children and adolescents less than 18 years of age who were hospitalised with PIMS-TS in Switzerland between March 2020 and March 2022. Data was collected from all 29 paediatric hospitals through the Swiss Paediatric Surveillance Unit (SPSU) during hospitalisation and approximately six weeks after discharge. The data was analysed after categorising the participants into three groups based on their admission status to the intensive care unit (ICU) (non-ICU, ICU-moderate) and the requirement for invasive ventilatory and/or inotropic support (ICU-severe). Overall, 204 children were included of whom 194 (95.1%) had follow-up data recorded. Median age was 9.0 years (interquartile range [IQR] 6.0-11.5) and 142 (69.6%) were male. In total, 105/204 (51.5%) required ICU admission, of whom 55/105 (52.4%) received inotropic support and 14/105 (13.3%) mechanical ventilation (ICU-severe group). Echocardiography was performed in 201/204 (98.5%) children; 132 (64.7%) had a cardiac abnormality including left ventricular systolic dysfunction (73 [36.3%]), a coronary artery abnormality (45 [22.4%]), pericardial effusion (50 [24.9%]) and mitral valve regurgitation (60 [29.9%]). Left ventricular systolic dysfunction was present at admission in 62/201 (30.8%) children and appeared during hospitalisation in 11 (5.5%) children. A coronary artery abnormality was detected at admission in 29/201 (14.2%) children and developed during hospitalisation or at follow-up in 13 (6.5%) and 3 (1.5%) children, respectively. None of the children had left ventricular systolic dysfunction at follow-up, but a coronary abnormality and pericardial effusion were found in 12 (6.6%) and 3 (1.7%) children, respectively. School absenteeism at the time of follow-up was more frequent in children who had been admitted to the ICU (2.5% in the non-ICU group compared to 10.4% and 17.6% in the ICU-moderate and ICU-severe group, respectively) (p = 0.011). Cardiac complications in children presenting with PIMS-TS are common and may worsen during the hospitalisation. Irrespective of initial severity, resolution of left ventricular systolic dysfunction is observed, often occurring rapidly during the hospitalisation. Most of the coronary artery abnormalities regress; however, some are still present at follow-up, emphasising the need for prolonged cardiac evaluation after PIMS-TS.

Complete and incomplete Kawasaki disease: Clinical differences and coronary artery outcome from a national prospective surveillance study in Switzerland.

The aim of this national prospective surveillance study was to compare the clinical presentation, laboratory findings, treatment, and coronary artery outcome in patients with incomplete and complete Kawasaki disease (KD). Between March 2013 and February 2019, children with a diagnosis of complete and incomplete KD were reported by the Swiss Paediatric Surveillance Unit and prospectively enrolled. Clinical data, laboratory values, treatment, and echocardiographic features were collected at diagnosis and 1 year of follow-up. Data were compared between children with complete or incomplete KD. A total of 351 questionnaires were registered from children with a diagnosis of KD. Of them, 219 (62.4%) children had complete KD, and 132 (37.6%) children had incomplete KD. Children with incomplete KD were younger and had a longer-lasting fever; however, there were no differences in the level of C-reactive protein. All but four children received intravenous immunoglobulin treatment, whereas 14% of children were treated with corticosteroids. Children with incomplete KD were more often treated with corticosteroids than children with incomplete KD (p = 0.01). At diagnosis, 39 (11.1%) patients had only coronary artery dilation and 57 (16.2%) had at least one coronary artery aneurysm. There were no differences in coronary artery involvement between the two groups. At follow-up, 273 of 294 (92.8%) patients had no coronary artery involvement, with no difference between the two groups (p = 0.609). The overall incidence of coronary artery aneurysms at diagnosis was 16.2%. At follow-up, most coronary artery aneurysms had regressed, and coronary artery aneurysms were present in only 5.8% of the patients. Coronary artery aneurysms were slightly more frequent in patients with incomplete KD at follow-up (p = 0.039) but not at diagnosis (p = 0.208). Although the clinical presentation in children with incomplete and complete KD differs, the absence of coronary artery involvement does not. The use of corticosteroids appears to be preventive against the development of coronary artery aneurysms in these patients. However, the results of this study suggest a lower rate of coronary artery aneurysm regression in patients with incomplete KD. Further studies on a larger scale are needed to assess the risk of non-regression of coronary artery aneurysms in this particular group of patients.

Neonates with SARS-CoV-2 infection: spectrum of disease from a prospective nationwide observational cohort study.

Coronavirus disease 2019 (COVID-19) can be more severe in infants than in older children. To date, only a few case series have reported data on neonates with COVID-19, including mostly asymptomatic neonates who were tested because of exposure to maternal SARS-CoV-2 infection. This study summarises nationwide epidemiological data, clinical characteristics, treatment and outcomes of neonates presenting with symptomatic SARS-CoV-2 infection. Data were prospectively collected through the Swiss Paediatric Surveillance Unit from hospitalised neonates with laboratory-confirmed SARS-CoV-2 infection (positive polymerase chain reaction on a respiratory sample) from 1 March 2020 to 31 September 2021. All 29 paediatric hospitals in Switzerland reported cases. In total, 73 neonates were included; 7 (10%) were preterm. The median age at presentation was 17 days (interquartile range [IQR] 11-23); 40 (55%) were female. The majority of neonates (64, 88%) were admitted from home. Nine (12%) had a pre-existing medical condition. Overall, the most common symptom recorded was fever in 52 (71%), followed by rhinorrhoea or nasal congestion in 32 (44%) and respiratory distress in 19 (26%). Twenty (27%) neonates presented with fever without a source. Seven (10%) neonates were admitted to an intensive care unit (5 for respiratory failure and 2 for monitoring). One (1%) neonate required inotropic support. The median length of hospital stay in term neonates was 4 days (IQR 3-5). Two (3%) were treated with corticosteroids and 1 (1%) with remdesivir. In total, 60 (82%) neonates had contact with a known or suspected SARS-CoV-2 index case. All of the 71 neonates for whom data were available were discharged to their homes without symptoms. In neonates, COVID-19 mainly presents with fever, and symptoms of upper and lower respiratory tract infection. The clinical course is mostly mild, requiring a short period of hospitalisation. COVID-19 needs to be added as a differential diagnosis in neonates who present with fever without a source. However, the presence of SARS-CoV-2 should not deter from the search for a serious bacterial infection. Further data from surveillance studies are needed to better understand COVID-19 in neonates, guide therapy and to evaluate whether the clinical spectrum is changing with new SARS-CoV-2 variants.

Epidemiology of Kawasaki Disease in children in Switzerland: a national prospective cohort study.

Kawasaki disease is a febrile illness which can lead to significant coronary artery lesions. Its incidence varies among countries and is highest in Japan (330.2 children under 5 years old/100,000 per year). Since the epidemiology of Kawasaki disease in Switzerland is unknown, we conducted a national prospective data collection between 2013 and 2017 to describe its incidence, diagnosis, and treatment. We collected demographic and clinical data of the children under 17 years old hospitalised with Kawasaki disease in Switzerland between March 2013 and February 2017 using anonymous data collection forms with the help of the Swiss Paediatric Surveillance Unit (SPSU). We defined Kawasaki disease per the 2004 American Heart Association criteria: patients with ≥5 days of fever and ≥4 of the 5 main clinical features were included as complete Kawasaki disease and patients with ≥5 days of fever and <4 of the 5 main clinical features were included as incomplete Kawasaki disease. The incidence was calculated with the data of the Federal Statistical Office of Switzerland, considering permanent residents of the country. The different groups were compared by the unpaired student t-test for continuous variables and Pearson's chi squared test for categorical variables, respectively. We included 175 patients: 60% were boys, with a mean age of 38.2 months. The incidence of Kawasaki disease was 3.1/100,000 [95% CI 2.6-3.7] per year in children under 17 years of age and 8.4/100,000 [95% CI 6.7-10.2] per year in children under 5 years of age. The most frequent clinical signs were a rash (85.4%) and changes of the lips and oral/pharyngeal mucosa (83.4%). The diagnosis of Kawasaki disease was made at a mean of 7.3 days after the first symptom. Echocardiography was abnormal in 52.3%. The treatment with intravenous immunoglobulins (IVIG) and acetylsalicylic acid was administered in accordance with international guidelines. Subgroup analysis showed that children older than 5 years old had significantly more complete Kawasaki disease than the younger ones (78.8% vs 57.4%, p = 0.021). Children with "extreme ages" (<1 year old and >8 years old) were diagnosed later (8.6 (±0.9) vs 7.0 (±0.3) days, p = 0.0129), had longer duration of fever (9.8 (±0.9) vs 8.1 (±0.3) days, p = 0.013) and had more echocardiographic abnormalities (n = 26 (70.3%) vs n = 65 (47.5%), p = 0.014) at diagnosis. One child died during the acute phase of the illness. The incidence of Kawasaki disease in Switzerland is in the lower range of other European countries.

Decline of pertussis in hospitalised children following the introduction of immunisation in pregnancy - results from a nationwide, prospective surveillance study, 2013-2020.

Surveillance of pertussis at a national level is important to collect information on the epidemiology of the disease and to design optimal immunisation strategies. After an initial surveillance period for pertussis in hospitalised children in Switzerland from 2006 to 2010, new recommendations (including immunisation in pregnancy) were implemented in the national pertussis immunisation schedule in 2013. To monitor its effects, surveillance was resumed in 2013 and concluded in 2020. From 1 January 2013 to 31 December 2020, hospitalised children under the age of 16 years with suspected or proven Bordetella pertussis infection were reported to the Swiss Paediatric Surveillance Unit. We analysed epidemiological and clinical characteristics for all patients who fulfilled the clinical case definition of pertussis (physician diagnosis, cough lasting ≥14 days in combination with at least one of the following symptoms: paroxysmal cough, whooping or post-tussive vomiting, or apnoea not otherwise explained in patients under the age of 12 months) with and without laboratory confirmation (polymerase chain reaction, culture or serology). 220 of the 306 reported cases met the inclusion criteria. Of these, 214 (97%) were laboratory-confirmed B. pertussis infections: 209 by polymerase chain reaction and 5 by culture from nasopharyngeal specimens. 172/220 (78%) patients were infants under six months of age at the day of hospitalisation. The mean annual hospitalisation rate for pertussis was 27.9 per 100,000 children for infants and 2.1 per 100,000 in all children <16 years of age. Of the 115 cases with precise records of immunisation, 50 (43%) were unimmunised, 3 (3%) were incompletely immunised and 62 (54%) were up to date with their immunisation status according to their age, including 10 (9%) whose next doses were due. However, most patients with an up-to-date immunisation status (85%) were still too young to have completed their primary series, leaving only eight cases of vaccine failure. Only 5 of the 172 infants <6 months of age had mothers who had been vaccinated during pregnancy. After the introduction of immunisation in pregnancy in Switzerland, hospitalisation rates in infants declined. However, the remaining cases call for increased efforts towards more complete and timely immunisation of children, those in close contact with children, and pregnant women.

Factors associated with hospital and intensive care admission in paediatric SARS-CoV-2 infection: a prospective nationwide observational cohort study

Coronavirus disease 2019 (COVID-19) is usually less severe in children compared to adults. This study describes detailed clinical characteristics, treatment and outcomes of children with COVID-19 in a non-hospitalised and hospitalised setting and quantifies factors associated with admission to hospital and intensive care unit in children with SARS-CoV-2 infection on a nationwide level. Data were collected through the Swiss Paediatric Surveillance Unit from children < 18 years with confirmed SARS-CoV-2 infection. All 33 paediatric hospitals in Switzerland reported non-hospitalised and hospitalised cases from March 1 to October 31, 2020 during both pandemic peaks. In total, 678 children were included. The median age was 12.2 years (IQR 5.0–14.6), 316 (46.6%) were female and 106 (15.6%) had comorbidities. Overall, 126 (18.6%) children were hospitalised of whom 16 (12.7%) required ICU admission. Comorbidities were the only factor associated with hospital admission in a multivariable regression analysis (odds ratio 3.23, 95%CI 1.89 to 5.50; p-value < 0.01). Children with preexisting comorbidities did not require ICU admission more often. Hospitalised children more often presented with fever (96 [76.2%] vs 209 [38.1%], p-value < 0.01) and rash (16 [12.8%] vs 6 [1.1%], p-value < 0.01). Anosmia/dysgeusia was more prevalent in non-hospitalised children (73 [13.3%] vs 3 [2.4%], p-value < 0.01). In hospitalised children, oxygen treatment was required in 34 (27.0%), inotropes in nine (7.3%) and mechanical ventilation in eight (6.3%) cases. Complications were reported in 28 (4.1%) children with cardiovascular complications being most frequent (12 [1.8%]). Three deaths were recorded.Conclusion: This study confirms that COVID-19 is mostly a mild disease in children. Fever, rash and comorbidities are associated with higher admission rates. Continuous observation is necessary to further understand paediatric COVID-19, guide therapy and evaluate the necessity for vaccination in children.What is Known:• Clinical manifestations of SARS-CoV-2 infection in children vary from asymptomatic to critical disease requiring intensive care unit admission.• Most studies are based on hospitalised children only; currently, there is limited data on non-hospitalised children.What is New:• The clinical spectrum and severity of COVID-19 is influenced by age: in children less than 2 years, fever, cough and rhinorrhoea are the most common symptoms and in adolescents, fever, cough and headache are more common.• Hospitalised children more often presented with fever and rash, while anosmia/dysgeusia is more prevalent in non-hospitalised children.• Children with pre-existing comorbidities are more frequently hospitalised but do not require ICU admission more often.

Subclinical Tuberculosis in Children: Diagnostic Strategies for Identification Reported in a 6-year National Prospective Surveillance Study.

Subclinical tuberculosis (TB) is well recognized and defined as a disease state with absent or nonrecognized symptoms. The study identifies factors associated with subclinical TB and diagnostic strategies in a low-burden, high-resource country. Data were collected between December 2013 and November 2019 through the Swiss Pediatric Surveillance Unit (SPSU). Children with culture/molecular confirmed TB, or who were treated with ≥3 antimycobacterial drugs, were included. A total of 138 (80%) children with TB disease were included in the final analysis, of which 43 (31%) were subclinical. The median age of children with subclinical compared to symptomatic TB was 3.7 (interquartile range [IQR] 2.2-7) and 9.7 (IQR 2.7-14.3) years, respectively (P = .003). The cause of investigation for TB was recorded in 31/43 (72.1%) of children with subclinical TB and included contact exposure in 25 (80.6%) of children. In children with subclinical TB, diagnosis was made by a combination of the following abnormal/confirming results: culture/molecular + immunodiagnostic + chest radiography in 12 (27.9%) cases, immunodiagnostic + chest radiography in 19 (44.2%) cases, culture/molecular + chest radiography in 2 (4.7%) cases, culture + immunodiagnostic in 1 (2.3%) case, chest radiography only in 8 (18.6%) cases, and immunodiagnostic only in 1 (2.3%) case. A notable proportion of children with TB had subclinical disease. This highlights the importance of non-symptom-based TB case finding in exposed children and refugees from high-TB-prevalence settings. TB screening in these asymptomatic children should therefore include a combination of immunodiagnostic testing and imaging followed by culture and molecular testing.

Pediatric Tuberculosis Disease during Years of High Refugee Arrivals: A 6-Year National Prospective Surveillance Study

Background: In Europe, surveillance and monitoring of pediatric tuberculosis (TB) remains important, particularly in the light of migration in recent years. The aim of the study was to evaluate incidence rates of childhood TB and detailed diagnostic pathways and treatment. Methods: Data were collected through the Swiss Pediatric Surveillance Unit (SPSU) from December 2013 to November 2019. Monthly ­notifications are obtained from the 33 pediatric hospitals in the SPSU, and a detailed questionnaire was sent out upon notification. Inclusion criteria were children and adolescents aged up to 15 years with culture- or molecular-confirmed TB disease or for whom a treatment with ≥3 antimycobacterial drugs had been initiated. Data were compared with age-matched notification data from the Swiss Federal Office of Public Health (FOPH). Results: Of the 172 cases notified to SPSU, a detailed questionnaire was returned for 161 (93%) children, of which 139 met the inclusion criteria. Reasons for exclusion were age >15 years, double reporting, and not fulfilling the criteria for TB disease. During the same time period, 172 pediatric TB cases were reported to the FOPH, resulting in an incidence of 2.1 per 100,000, ranging from 1.4 to 2.8 per year, without a clear trend over time. In the 64 (46.0%) foreign-born children, incidence rates were higher and peaked in 2016, with 13.7 per 100,000 (p = 0.018). The median interval between arrival in Switzerland and TB diagnosis was 5 (IQR 1–21) months, and 80% were diagnosed within 24 months of arrival. In 58% of the cases, TB disease was confirmed by culture or molecular assays. Age >10 years, presence of fever, or weight loss were independent factors associated with confirmed TB. Conclusion: The annual pediatric TB incidence rate only varied among foreign-born children and was highest in 2016 when refugee influx peaked in Europe. Importantly, most foreign-born children with TB were diagnosed within 2 years after arrival in Switzerland. Thus, the early period after arrival in Switzerland is associated with a higher risk of TB disease in children, and this should be considered for screening guidance in refugees.

Listeriosis in infants: Prospective surveillance studies in Canada and Switzerland.

International data on listeriosis during infancy from large populations are essential to guide evidence-based empiric antibiotic guidelines for sepsis in infancy. We aimed to determine the incidence, clinical manifestations, and outcome of listeriosis in infants <6 months of age in Canada and Switzerland. Prospective, active surveillance of listeriosis in infants <6 months of age was conducted through the Canadian Paediatric Surveillance Program (May 2015 to April 2017) and the Swiss Paediatric Surveillance Unit (April 2017 to March 2018). Confirmed and probable cases were included. In Canada, eight sporadic listeriosis cases were reported (incidence, 1.1/100,000 live births/year). In Switzerland, four cases were reported (incidence, 4.5/100,000 live births/year) of which three were part of a confirmed outbreak with an unclear source. In the two countries, eight of the 12 cases (66.6%) presented as early-onset disease (within the first 7 days of life) and none presented after 28 days life. Neonatal listeriosis is rare. Infants presenting with sepsis, especially after 4 weeks of life, may not routinely require empiric antibiotic coverage for listeriosis. Outbreak-related cases still occur. Continued surveillance is important.

Factors Associated with Hospital and Intensive Care Admission in Paediatric SARS-CoV-2 Infection: A Prospective Nationwide Observational Cohort Study

Background: Coronavirus disease 2019 (COVID-19) is usually less severe in children compared to adults. This study describes detailed clinical characteristics, treatment and outcomes of children with laboratory-confirmed COVID-19 in a non-hospitalised and hospitalised setting and quantifies factors associated with admission to hospital and intensive care unit in children with SARS-CoV-2 infection on a nationwide level.Methods: Data were collected through the Swiss Paediatric Surveillance Unit from children Findings: In total, 678 children were included. The median age was 12.2 (IQR 5.0 – 14.6) years, 316 (47%) were female and 106 (16%) had comorbidities. Overall, 126 (18.6%) children were hospitalised of whom 16 (12.7%) required ICU admission. Comorbidities were the only factor associated with hospital admission in a multivariable regression analysis (odds ratio 3.23, 95%CI 1.89 to 5.50; p-value Interpretation: This study confirms that COVID-19 is mostly a mild disease in children. Fever, rash, and comorbidities are associated with higher admission rates. Continuous observation is necessary to further understand paediatric COVID-19, guide therapy and evaluate the necessity for vaccination in children.Funding: The study is supported by the Swiss Federal Office of Public Health and has received grants from the Swiss Society of Paediatrics and the Paediatric Infectious Disease Group of Switzerland.Declaration of Interest: None to declare.Ethical Approval: The study has received ethical approval by the Ethikkommission Nordwest- undZentralschweiz (EKNZ 2020-01130).

Clinical and Epidemiologic Characteristics of Pertussis in Hospitalized Children: A Prospective and Standardized Long-term Surveillance Study.

Surveillance of incidence and severity of pertussis is key to control success and shortcomings of vaccination programs followed by adaptations of recommendations if necessary. In Switzerland, nationwide reporting of hospitalizations due to pertussis in children has a long tradition and resumed in 2013 to evaluate the effects of pertussis immunization in pregnancy introduced in 2013. Since 2013, all patients <16 years of age hospitalized with suspected or proven pertussis have been reported to the Swiss Pediatric Surveillance Unit. Patient data comprising clinical and epidemiologic characteristics and laboratory confirmation were assessed in a standardized fashion, and case definitions were applied to all cases reported until the end of 2019. Two hundred thirteen of 294 cases were valid cases of pertussis. Of these, 168 (79%) occurred in <6-month-old infants. Mean duration of hospitalization was 8 days (median 5, range 2-47) overall and highest in neonates (14.2 days); 85% of all patients had ≥1 complication, most commonly cyanosis and dyspnea, especially in infants. Overall, case fatality rate was 1.4% (8.7% in neonates). Only 4 (2%) of 168 mothers of infants <6 months had been vaccinated during pregnancy; 14 (12%) of 112 patients with precise records of immunization had completed their primary series and were up-to-date for age. Despite a decline of cases associated with the introduction of immunization against pertussis in pregnancy, control of the disease remains challenging, mainly due to failure to vaccinate rather than vaccine failure.

Swiss national prospective surveillance of paediatric Mycoplasma pneumoniae-associated encephalitis.

To assess the presence of Mycoplasma pneumoniae-associated encephalitis in children in Switzerland and its likely pathogenesis. M. pneumoniae-associated encephalitis cases seen at a single-centre during 2010-2013 were reviewed, and the Swiss Paediatric Surveillance Unit (SPSU) prospectively conducted a nationwide surveillance 2013-2015. Case definition included confirmed, probable and possible cases. Seven patients (median age 8.7 years, range 4.7-10.1 years) with confirmed or possible M. pneumoniae-associated encephalitis were observed. All patients manifested prodromal respiratory symptoms over at least 5 days and five out of the six who had a chest radiograph, showed pulmonary infiltrates. M. pneumoniae DNA in cerebrospinal fluid was negative in all patients. Intrathecally synthesised M. pneumoniae-specific immunoglobulin (IgM and IgG) were investigated and found positive in one patient (confirmed case). M. pneumoniae DNA in respiratory specimens and/or M. pneumoniae-specific IgM and IgG in serum were detected in the other six patients (possible cases). One confirmed and two possible cases had neurological sequelae at 4-19 months follow-up. The lack of detectable M. pneumoniae DNA in cerebrospinal fluid of our encephalitis patients suggests a likely immune-mediated pathogenesis ignited by a respiratory inflammatory process including pneumonia.

Prospective Nationwide Surveillance of Hospitalizations Due to Pertussis in Children, 2006–2010

Frequency of pertussis is highly variable from country to country and it depends on multiple factors including case definitions and type of surveillance systems used. Many countries recently reported an increase of pertussis cases especially in infants and adolescents. From April 2006 to March 2011, 15-year-old patients hospitalized with suspected or proven pertussis were reported to the Swiss Pediatric Surveillance Unit. Patients with ≥14 days of cough plus paroxysms, whooping or post-tussive vomiting fulfilled the clinical case definition of pertussis. For laboratory confirmation, Bordetella pertussis polymerase chain reaction was offered free of charge. Data were available from 159 of 173 reported cases and 130 (90% of them <12 months old) were eligible including 125 laboratory-confirmed B. pertussis infections. Rates per 100,000 population were 2.6 (<16 years) and 38.8 (<12 months), respectively. Most frequent complications were cyanosis (63%) and sleep disturbance (60%); 35 (27%) patients received intensive care and 1 patient died. Source of infection was known in 79 (61%) patients and was mainly a sibling, parent or both. Most patients were unimmunized (65%) or incompletely immunized (30%). The high rate of pertussis hospitalization in young infants established in this surveillance project and the incomplete pertussis immunization status in almost all hospitalized patients require further efforts for improvement. In addition, introduction of pertussis immunizations for all adolescents (in 2013), young adults (in 2012) and pregnant women (in 2013) in Switzerland should increase indirect protection of vulnerable newborns and infants too young to be fully immunized.

Prevention of vitamin K deficiency bleeding with three oral mixed micellar phylloquinone doses: results of a 6-year (2005–2011) surveillance in Switzerland

In 2003, the Swiss guidelines to prevent vitamin K deficiency bleeding (VKDB) were adapted. As two oral doses (2 mg, hour/day 4) of mixed micellar VK preparation had failed to abolish late VKDB, a third dose (week 4) was introduced. This report summarizes the new guidelines acceptance by Swiss pediatricians and the results of a prospective 6-year surveillance to study their influence on the incidence of VKDB. The new guidelines acceptance by Swiss pediatricians was evaluated by a questionnaire sent to all pediatricians of the Swiss Society of Paediatrics. With the help of the Swiss Paediatric Surveillance Unit, the incidence of VKDB was monitored prospectively from July 1, 2005 until June 30, 2011. Over a 6-year period (458,184 live births), there was one case of early and four cases of late VKDB. Overall incidence was 1.09/10(5) (95 % confidence intervals (CI) 0.4-2.6). Late VKDB incidence was 0.87/10(5) (95 % CI 0.24-2.24). All four infants with late VKDB had an undiagnosed cholestasis at the time of bleeding; parents of 3/4 had refused VK prophylaxis, and in 1/4, the third VK dose had been forgotten. Compared with historical control who had received only two oral doses of mixed micellar VK (18 cases for 475,372 live births), the incidence of late VKDB was significantly lower with three oral doses (Chi(2),Yates correction, P = 0.007). VKDB prophylaxis with 3 × 2 mg oral doses of mixed micellar VK seems to prevent adequately infants from VKDB. The main risk factors for VKDB in breast-fed infants are parental VK prophylaxis refusal or an unknown cholestasis.

Neonatal herpes simplex virus infections in Switzerland: results of a 6-year national prospective surveillance study

A large variation in neonatal herpes incidence is observed in USA and Europe. Better knowledge of neonatal herpes epidemiology is important to inform local prevention strategies. Between 2002 and 2008, the Swiss Paediatric Surveillance Unit reported prospectively proven neonatal herpes simplex virus infections. During the study period seven cases were declared, for an incidence of 1.6/100 000 (95% CI 0.64–3.28/100 000) live births. This is one of the lowest incidences of neonatal herpes reported.

Shaken baby syndrome in Switzerland: results of a prospective follow-up study, 2002–2007

Since the incidence of shaken baby syndrome in Switzerland was not known, we conducted a nationwide prospective follow-up study for a 5-year period (from 2002 to 2007). The data were collected through the Swiss Pediatric Surveillance Unit. Inclusion criteria were the presence, in a child <or=6 years of age, of 1) more than or equal to two clinical symptoms (altered consciousness, convulsions, respiratory irregularities, and bulging fontanel), 2) one eye finding (retinal hemorrhages, vitreous hemorrhages), 3) one MRI/CT finding (subdural hematoma, subarachnoid hematoma, and parenchymatous lesions), or 4) history of shaking. Exclusion criteria were age >6 years or documented accident/disease explaining symptoms/findings. To describe outcome, we used the King's Outcome Scale for Childhood Head Injury (KOSCHI). 56 cases were reported from 13 of 26 Swiss cantons, representing 80% of the Swiss population; 49 cases met the inclusion criteria. Preponderance of male infants was high (31 male and 18 female); median age at admission was 4 months (1-58). Clinical symptoms were present in 42 infants, retinal/vitreous hemorrhages in 39 infants, and pathological brain/head imaging in 46 infants. In 13 cases, the caregivers admitted shaking the child. Outcomes (KOSCHI 1-5; n = 47 patients) were death (KOSCHI 1) 8 (17.7%), vegetative state (KOSCHI 2) 0, severe disability (KOSCHI 3) 11 (22.2%), moderate disability (KOSCHI 4) 14 (31.1%), and good recovery (KOSCHI 5) 14 (28.8%). Based on these data, the incidence of shaken baby syndrome in Switzerland is 14 per 100 000 live births, which corresponds to the incidence in other Western countries. Demographic characteristics and outcomes of Swiss patients were comparable to published studies.

Hemolytic-uremic syndrome in Switzerland: a nationwide surveillance 1997–2003

Hemolytic-uremic syndrome (HUS) is a leading cause of acute renal failure in childhood. In its typical presentation, it is preceded by an episode of diarrhea mostly due to Shiga-toxin-producing Escherichia coli. There is important geographical variation of many aspects of this syndrome. Nationwide data on childhood HUS in Switzerland have not been available so far. In a prospective national study through the Swiss Pediatric Surveillance Unit 114 cases (median age 21 months, 50% boys) were reported between April 1997 and March 2003 by 38 pediatric units (annual incidence 1.42 per 10(5) children < or =16 years). Shiga-toxin-producing E. coli were isolated in 32 (60%) of tested stool samples, serotype O157:H7 in eight. Sixteen children presented with only minimal renal involvement, including three with underlying urinary tract infection. Six patients presented with atypical hemolytic-uremic syndrome, and six with HUS due to invasive Streptococcus pneumoniae infection. Mortality was 5.3%, including two out of six children with S. pneumoniae infection. The severity of thrombocytopenia and the presence of central nervous system involvement significantly correlated with mortality. In conclusion, childhood HUS is not rare in Switzerland. Contrasting other countries, E. coli O157:H7 play only a minor role in the etiology. Incomplete manifestation is not uncommon.

Three-Year Surveillance of Intussusception in Children in Switzerland

We attempted to obtain baseline data on the incidence of intussusception and its association with gastroenteritis in a cross-sectional observational study in children. Admissions to all 38 pediatric units in Switzerland because of intussusception were reported to the Swiss Pediatric Surveillance Unit from April 2003 to March 2006. Patient and disease characteristics were assessed prospectively with the use of a standardized questionnaire based on the case definition for intussusception developed by the Brighton Collaboration. Completeness of reporting was verified through capture-recapture analysis. There were 294 patients with reported intussusception; 35 cases were excluded for various reasons, and 29 additional patients were identified through International Classification of Diseases, 10th Revision, codes. After capture-recapture analysis, we estimated underreporting to the Swiss Pediatric Surveillance Unit to be 32% and we calculated a true number of 381 intussusception episodes. The highest level of diagnostic certainty was reached by 248 patients, and 20 fulfilled level 2 criteria; for the remaining 20 patients, available information was insufficient. The mean age of the patients was 2.7 years. The yearly mean incidence of intussusception was 38, 31, and 26 cases per 100,000 live births in the first, second, and third year of life, respectively, with no apparent seasonality. Seventy patients had a history of coinciding gastroenteritis, and 5 of 61 tested positive for rotavirus. Spontaneous devagination was observed for 38 patients; enemas reduced intussusception successfully in 183 cases, whereas surgical treatment was required in 67. All patients recovered without sequelae. This is the first prospective nationwide surveillance of intussusception in childhood using a standardized case definition. Most cases occurred beyond infancy, and association with rotavirus gastroenteritis was rare.

Evaluation of the Brighton Collaboration case definition of acute intussusception during active surveillance

To evaluate the Brighton Collaboration case definition of acute intussusception, we reviewed all episodes reported to the Swiss Paediatric Surveillance Unit (SPSU) during 1 year (4/2003–3/2004). Of 96 confirmed episodes 86 (90%, 95% CI 83–96) were captured by the case definition. Of the remaining 10 episodes, 9 resolved spontaneously following presentation with clinical signs and symptoms, and ultrasound findings compatible with intussusception. Eighty-two episodes met level 1 of the definition, the highest level of diagnostic certainty. Compared to level 1, the sensitivity of level 2 (intermediate level) and level 3 (lowest level) was 65% (CI 55–74) and 30% (CI 20–40), respectively. In conclusion, the case definition was useful and applicable to assess the background rate of intussusception in the light of potential future rotavirus immunization.

Prospective surveillance of hospitalisations associated with varicella-zoster virus infections in children and adolescents

Our goal was to determine the epidemiology of severe varicella-zoster virus (VZV) infections in hospitalised paediatric patients. Admissions associated with VZV infection of patients aged 0-16 years were reported by all 38 paediatric units in Switzerland to the Swiss Paediatric Surveillance Unit (SPSU) during 3 consecutive years (4/2000-3/2003). We verified completeness of reporting by capture-recapture analysis with patient records identified by ICD-10 codes. Outcome of illness was assessed 6 months after hospitalisation. A total of 335 cases (235 identified by SPSU reports, 100 by ICD-10 code) were included in this study. Mean age of patients was 4.1 years (median 3.5 years, range 0-16 years); 54% were male. Some 293 (87%) patients presented with chickenpox, 42 (13%) with herpes zoster and 291 (87%) patients were not immunocompromised. A total of 319 complications occurred in 237 (71%) patients: secondary bacterial infections (n =109); central nervous system involvement (n =76); VZV pneumonitis (n =7); others (n =127). Eleven (3%) patients required intensive care and three died. On follow-up, 303 (96%) of 315 patients had completely recovered; sequelae were present in 12 (4%) patients. The calculated hospitalisation rate was 13 per 10(4) cases. This study describes a sizeable hospitalisation and complication rate of varicella-zoster virus infections and provides a solid basis for future immunisation recommendations in Switzerland.