The Value of Warning Signs From the WHO 2009 Dengue Classification in Detecting Severe Dengue in Children

BACKGROUND

World Health Organization proposed 7 warning signs to identify the risk of severe dengue in 2009. This study aimed to evaluate the value of these warning signs in detecting severe dengue in children.

MATERIAL AND METHODS

A cross-sectional study was conducted utilizing data of children with clinical dengue infection obtained from medical records between January 2009 and December 2018 in Jakarta. Children with confirmed dengue were analyzed and stratified into 3 age groups: infants less than 1 year old, children 1-14 years and adolescents 15-18 years of age. Positive predictive value, negative predictive value (NPV), sensitivity and specificity of each warning sign present or absent on admission in detecting severe dengue were computed.

RESULTS

Six hundred ninety-nine children with clinical dengue infection were enrolled, among whom 614 (87.8%) had confirmed dengue infection, either by antigen or antibody serological tests. Severe dengue occurred in 211/614 (34.4%) cases. In infants, important warning signs on admission to detect or exclude severe dengue were liver enlargement (NPV 80.8%) and clinical fluid accumulation (NPV 75%). In children and adolescents, warning sign with highest NPV (in children 76.6% and in adolescents 91.9%) was increase in hematocrit concurrent with a rapid decrease in platelet count. Other warning signs with high NPV values in children were abdominal pain (72%), vomiting (70%), clinical fluid accumulation (69.3%), and in adolescents' abdominal pain (80.7%), vomiting (75.7%), clinical fluid accumulation (82.7%). NPVs increase with more than 1 warning sign in all age groups.

CONCLUSION

In infants, liver enlargement or clinical fluid accumulation are important warning signs for severe dengue, when both are absent, severe dengue is unlikely. In older children and adolescents, an increase in hematocrit with the concurrent rapid decrease in platelet count is most discriminative; followed by the absence of abdominal pain, vomiting or fluid accumulation are unlikely severe dengue.

Education pathways and key tasks for research nurses in Europe, results from a VACCELERATE online survey

AIM

This article aims to provide a comprehensive overview of the educational pathways and responsibilities of research nurses in Europe, particularly focusing on their essential role in conducting research in clinical settings, including clinical trials, while adhering to ethical and regulatory standards.

BACKGROUND

Research nurses play a crucial role in clinical research settings, especially in clinical trials, ensuring adherence to ethical and regulatory standards. Understanding their educational pathways and responsibilities is essential for promoting consistency and quality in research practices across Europe.

DESIGN

Between October and November 2022, relevant European nursing education authorities, including those focused on research nursing, were contacted to participate in an online cross-sectional survey. The survey aimed to gather information about research nurse education and training in their respective countries.

METHODS

The study followed a cross-sectional design. Contacts were made with European nursing education authorities based on recommendations from the VACCELERATE National Coordinators and the VACCELERATE Site Network. Participating organizations were invited to complete an online survey regarding research nurse education in their countries.

RESULTS

Responses were obtained from 37 European countries, a response rate of 74%. The most common terms used to refer to nurses involved in clinical trials and epidemiological studies were "study nurse" (62%) and "clinical research nurse" and "research nurse" (43% each). The requirements to become a research nurse varied across countries, with a nursing degree necessary in 87% of countries and Good Clinical Practice (GCP) courses mandatory in 81%. Local providers of research nurse courses existed in 84% of countries, coordinated by online organisations (51%) or universities/hospitals (46%). The most common tasks assigned to research nurses were the administration of investigational medicinal products (from 78% in observational studies to 89% in phase IV trials) and blood sample processing (84% in phase II and IV trials).

CONCLUSIONS

This study provides valuable insights into research nurse education and tasks in European countries. It highlights the need for standardisation to enhance consistency and quality of training across Europe.

Estimation of introduction and transmission rates of SARS-CoV-2 in a prospective household study

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.

Childhood infection burden, recent antibiotic exposure and vascular phenotypes in preschool children

BACKGROUND

Severe childhood infection has a dose-dependent association with adult cardiovascular events and with adverse cardiometabolic phenotypes. The relationship between cardiovascular outcomes and less severe childhood infections is unclear.

AIM

To investigate the relationship between common, non-hospitalised infections, antibiotic exposure, and preclinical vascular phenotypes in young children.

DESIGN

A Dutch prospective population-derived birth cohort study.

METHODS

Participants were from the Wheezing-Illnesses-Study-Leidsche-Rijn (WHISTLER) birth cohort. We collected data from birth to 5 years on antibiotic prescriptions, general practitioner (GP)-diagnosed infections, and monthly parent-reported febrile illnesses (0-1 years). At 5 years, carotid intima-media thickness (CIMT), carotid artery distensibility, and blood pressure (BP) were measured. General linear regression models were adjusted for age, sex, smoke exposure, birth weight z-score, body mass index, and socioeconomic status.

RESULTS

Recent antibiotic exposure was associated with adverse cardiovascular phenotypes; each antibiotic prescription in the 3 and 6 months prior to vascular assessment was associated with an 18.1 μm (95% confidence interval, 4.5-31.6, p = 0.01) and 10.7 μm (0.8-20.5, p = 0.03) increase in CIMT, respectively. Each additional antibiotic prescription in the preceding 6 months was associated with an 8.3 mPa-1 decrease in carotid distensibility (-15.6- -1.1, p = 0.02). Any parent-reported febrile episode (compared to none) showed weak evidence of association with diastolic BP (1.6 mmHg increase, 0.04-3.1, p = 0.04). GP-diagnosed infections were not associated with vascular phenotypes.

CONCLUSIONS

Recent antibiotics are associated with adverse vascular phenotypes in early childhood. Mechanistic studies may differentiate antibiotic-related from infection-related effects and inform preventative strategies.

Estimation of introduction and transmission rates of SARS-CoV-2 in a prospective household study

Household studies provide an efficient means to study transmission of infectious diseases, enabling estimation of individual susceptibility and infectivity. A main inclusion criterion in such studies is often the presence of an infected person. This precludes estimation of the hazards of pathogen introduction into the household. Here we use data from a prospective household-based study to estimate SARS-CoV-2 age- and time-dependent household introduction hazards together with within household transmission rates in the Netherlands from August 2020 to August 2021. Introduction hazards and within-household transmission rates are estimated 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. The best fitting transmission models include 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 show that vaccination of adults could have strongly reduced infection attack rates in households and that adding adolescent vaccination would have offered limited added benefit.

VACCELERATE Site Network: Real-time definition of clinical study capacity in Europe

BACKGROUND

The inconsistent European vaccine trial landscape rendered the continent of limited interest for vaccine developers. The VACCELERATE consortium created a network of capable clinical trial sites throughout Europe. VACCELERATE identifies and provides access to state-of-the-art vaccine trial sites to accelerate clinical development of vaccines.

METHODS

Login details for the VACCELERATE Site Network (vaccelerate.eu/site-network/) questionnaire can be obtained after sending an email to. Interested sites provide basic information, such as contact details, affiliation with infectious disease networks, main area of expertise, previous vaccine trial experience, site infrastructure and preferred vaccine trial settings. In addition, sites can recommend other clinical researchers for registration in the network. If directly requested by a sponsor or sponsor representative, the VACCELERATE Site Network pre-selects vaccine trial sites and shares basic study characteristics provided by the sponsor. Interested sites provide feedback with short surveys and feasibility questionnaires developed by VACCELERATE and are connected with the sponsor to initiate the site selection process.

RESULTS

As of April 2023, 481 sites from 39 European countries have registered in the VACCELERATE Site Network. Of these, 137 (28.5 %) sites have previous experience conducting phase I trials, 259 (53.8 %) with phase II, 340 (70.7 %) with phase III, and 205 (42.6 %) with phase IV trials, respectively. Infectious diseases were reported as main area of expertise by 274 sites (57.0 %), followed by any kind of immunosuppression by 141 (29.3 %) sites. Numbers are super additive as sites may report clinical trial experience in several indications. Two hundred and thirty-one (47.0 %) sites have the expertise and capacity to enrol paediatric populations and 391 (79.6 %) adult populations. Since its launch in October 2020, the VACCELERATE Site Network has been used 21 times for academic and industry trials, mostly interventional studies, focusing on different pathogens such as fungi, monkeypox virus, Orthomyxoviridae/influenza viruses, SARS-CoV-2, or Streptococcus pneumoniae/pneumococcus.

CONCLUSIONS

The VACCELERATE Site Network enables a constantly updated Europe-wide mapping of experienced clinical sites interested in executing vaccine trials. The network is already in use as a rapid-turnaround single contact point for the identification of vaccine trials sites in Europe.

The impact of variant and vaccination on SARS-CoV-2 symptomatology; three prospective household cohorts

OBJECTIVES

We compared age-stratified SARS-CoV-2 symptomatology of wild-type/Alpha vs Omicron BA.1/BA.2 variant infected individuals and the impact of COVID-19 booster vaccination on Omicron symptom burden.

METHODS

Data from three European prospective household cohorts were used (April 2020 to April 2021 and January to March 2022). Standardized outbreak protocols included (repeated) polymerase chain reaction testing, paired serology, and daily symptom scoring for all household members. Comparative analyses were performed on 346 secondary household cases from both periods.

RESULTS

Children <12 years (all unvaccinated) experienced more symptoms and higher severity scores during Omicron compared with wild-type/Alpha period (P ≤0.01). In adults, Omicron disease duration and severity were reduced (P ≤ 0.095). Omicron was associated with lower odds for loss of smell or taste (adjusted odds ratio [aOR]: 0.14; 95% CI 0.03-0.50) and higher but non-significant odds for upper respiratory symptoms, fever, and fatigue (aORs: 1.85-2.23). No differences were observed in disease severity or duration between primary vs booster series vaccinated adults (P ≥0.12).

CONCLUSION

The Omicron variant causes higher symptom burden in children compared with wild-type/Alpha and lower in adults, possibly due to previous vaccination. A shift in symptoms occurred with reduction in loss of smell/taste for Omicron. No additional effect of booster vaccination on Omicron symptom burden was observed.

Enhancing public health communication of vaccine trials: The pan-European VACCELERATE Toolkit

BACKGROUND

The pan-European VACCELERATE network aims to implement the first transnational harmonised and sustainable vaccine trial Volunteer Registry, serving as single entry-point for volunteers willing to participate in large scale vaccine clinical studies across the European region. The present work exhibits a set of harmonised vaccine trial educational and promotional tools for the general public, designed and disseminated by the pan-European VACCELERATE network.

OBJECTIVE

The main objectives of the present study are the design and creation of a standard toolkit to increase positive attitudes, and access to trustful information for better access and increased recruitment to vaccine trials for the public community. More specifically, the produced tools are focused on inclusiveness, equity, and they are targeting different population groups, including underserved ones, as potential volunteers for the VACCELERATE Volunteer Registry (elderly, migrants, children and adolescents). The promotion/education material is aligned with the main objectives of the Volunteer Registry, to increase public literacy and awareness regarding vaccine clinical research/trials and trial participation, such as informed consent and legal issues, side effects and frequently asked questions on vaccine trial design.

METHODS

The tools' development has followed the aims and principles of the VACCELERATE project, focusing on trial inclusiveness and equity and they are adjusted to the local country requirements to improve public health communication. The selection of the produced tools has been based on the cognitive theory, inclusiveness and equity of different aged and under-represented groups, and standardised material from several official trustful sources (e.g. COVAX, ECDC, EUPATI, GAVI and WHO). In addition, team of specialists from different fields (infectious diseases, vaccine research, medicine, education) edited and reviewed the subtitles and scripts for the educational videos, extended brochures, interactive cards and puzzles. Graph designers also selected the colour palette, audio settings and dubbing for the video story-tales and implementation of QR codes.

RESULTS

This study presents the first set of harmonised promotional and educational materials/tools (i.e. educational cards, educational and promotional videos, extended brochures, flyers, posters, and puzzles) for vaccine clinical research (e.g. COVID-19). The developed tools inform the public about possible benefits and disadvantages of trial participation, but also build the confidence of participants about the safety and efficacy for COVID-19 vaccines and healthcare system. The present material has been translated into several languages and meant to be freely and easily accessible to facilitate dissemination among the participating countries of the VACCELERATE network, as well as among the European and global scientific, industrial, and public community, in general.

CONCLUSIONS

The produced material could also be useful for filling knowledge gaps of healthcare personnel and providing the appropriate future patient education for vaccine trials, as well as to tackle vaccine hesitancy and parents' concerns for potential participation of children in vaccine trials.

Feasibility of a hybrid clinical trial for respiratory virus detection in toddlers during the influenza season

BACKGROUND

Traditional clinical trials are conducted at investigator sites. Participants must visit healthcare facilities several times for the trial procedures. Decentralized clinical trials offer an interesting alternative. They use telemedicine and other technological solutions (apps, monitoring devices or web platforms) to decrease the number of visits to study sites, minimise the impact on daily routine, and decrease geographical barriers for participants. Not much information is available on the use of decentralization in randomized clinical trials with vaccines.

METHODS

A hybrid clinical trial may be assisted by parental recording of symptoms using electronic log diaries in combination with home collected nasal swabs. During two influenza seasons, children aged 12 to 35 months with a history of recurrent acute respiratory infections were recruited in 12 primary health centers of the Valencia Region in Spain. Parents completed a symptom diary through an ad hoc mobile app that subsequently assessed whether it was an acute respiratory infection and requested collection of a nasal swab. Feasibility was measured using the percentage of returned electronic diaries and the validity of nasal swabs collected during the influenza season. Respiratory viruses were detected by real-time PCR.

RESULTS

Ninety-nine toddlers were enrolled. Parents completed 10,476 electronic diaries out of the 10,804 requested (97%). The mobile app detected 188 potential acute respiratory infections (ARIs) and requested a nasal swab. In 173 (92%) ARI episodes a swab was taken. 165 (95.4%) of these swabs were collected at home and 144 (87.3%) of them were considered valid for laboratory testing. Overall, 152 (81%) of the ARIs detected in the study had its corresponding valid sample collected.

CONCLUSIONS

Hybrid procedures used in this clinical trial with the influenza vaccine in toddlers were considered adequate, as we diagnosed most of the ARI cases on time, and had a valid swab in 81% of the cases. Hybrid clinical trials improve participant adherence to the study procedures and could improve recruitment and quality of life of the participants and the research team by decreasing the number of visits to the investigator site. This report emphasises that the conduct of hybrid CTs is a valid alternative to traditional CTs with vaccines. This hybrid CT achieved high adherence of participant to the study procedures.

TRIAL REGISTRATION

2019-001186-33 (EudraCT).

Impact analysis of rotavirus vaccination in various geographic regions in Western Europe

BACKGROUND

Universal mass vaccination (UMV) against rotavirus has been implemented in many but not all European countries. This study investigated the impact of UMV on rotavirus incidence trends by comparing European countries with UMV: Belgium, England/Wales and Germany versus countries without UMV: Denmark and the Netherlands.

METHODS

For this observational retrospective cohort study, time series data (2001-2016) on rotavirus detections, meteorological factors and population demographics were collected. For each country, several meteorological and population factors were investigated as possible predictors of rotavirus incidence. The final set of predictors were incorporated in negative binomial models accounting for seasonality and serial autocorrelation, and time-varying incidence rate ratios (IRR) were calculated for each age group and country separately. The overall vaccination impact two years after vaccine implementation was estimated by pooling the results using a random effects meta-analyses. Independent t-tests were used to compare annual epidemics in the pre-vaccination and post-vaccination era to explore any changes in the timing of rotavirus epidemics.

RESULTS

The population size and several meteorological factors were predictors for the rotavirus epidemiology. Overall, we estimated a 42% (95%-CI 23;56%) reduction in rotavirus incidence attributable to UMV. Strongest reductions were observed for age-groups 0-, 1- and 2-years (IRR 0.47, 0.48 and 0.63, respectively). No herd effect induced by UMV in neighbouring countries was observed. In all UMV countries, the start and/or stop and corresponding peak of the rotavirus season was delayed by 4-7 weeks.

CONCLUSIONS

The introduction of rotavirus UMV resulted in an overall reduction of 42% in rotavirus incidence in Western European countries two years after vaccine introduction and caused a change in seasonal pattern. No herd effect induced by UMV neighbouring countries was observed for Denmark and the Netherlands.

Acute Gastroenteritis Disease Burden in Infants With Medical Risk Conditions in the Netherlands

BACKGROUND

Infants with medical risk conditions are vulnerable to childhood infections including acute gastroenteritis (AGE). To guide prevention programs, we quantified AGE incidence, severity and virus prevalence among medical risk infants in the Netherlands.

METHODS

This prospective cohort-study was part of the RIVAR-project recruiting infants with prematurity, low birth weight or severe congenital conditions in 13 hospitals. Follow-up included 18 monthly health questionnaires detailing AGE symptoms and healthcare usage. Parents were also instructed to notify when an infant developed AGE, to collect a stool sample and complete a daily severity score (Modified Vesikari Severity). Stool samples were analyzed by real-time polymerase chain reaction for rotavirus, norovirus, adenovirus and astrovirus.

RESULTS

Between November 2014 and October 2017, 631 infants participated during 9125 person-months of observation. In total, 559 episodes were identified. The mean AGE incidence rate was 73.5 per 100 person-years (PY) (95% confidence interval: 67.6-79.9) and increased with age [incidence rate: 48.3 (39.8-58.3) vs. 80.2 (73.0-88.1)/100 PY for ages 1-5 vs. 6-18 months, respectively]. Healthcare was attended for 38.1% (213/559) and 26.8% (68/254) were classified as severe based on the Modified Vesikari Severity. Stool samples were obtained from 254 AGE episodes. Norovirus was identified in 65 (25.6%) and rotavirus in 44 (17.7%). Adenovirus and astrovirus together accounted for 8.3% (N = 21). Severe AGE occurred most frequently in rotavirus positive episodes.

CONCLUSION

The observed AGE incidence, severity and healthcare usage among medical risk infants confirms substantial disease burden. Norovirus and rotavirus are the dominant pathogens and severe episodes occurred most frequently in children with rotavirus infection. AGE prevention in medical risk infants should be prioritized.

Transmission of SARS-CoV-2 infection among children in summer schools applying stringent control measures in Barcelona, Spain

BACKGROUND

Understanding the role of children in SARS-CoV-2 transmission is critical to guide decision-making for schools in the pandemic. We aimed to describe the transmission of SARS-CoV-2 among children and adult staff in summer schools.

METHODS

During July 2020 we prospectively recruited children and adult staff attending summer schools in Barcelona who had SARS-CoV-2 infection. Primary SARS-CoV-2 infections were identified through: (1) surveillance program in 22 summer schools' of 1905 participants, involving weekly saliva sampling for SARS-CoV-2 RT-PCR during 2-5 weeks; (2)cases identified through the Catalonian Health Surveillance System of children diagnosed with SARS-CoV-2 infection by nasopharyngeal RT-PCR. All centres followed prevention protocols: bubble groups, hand washing, facemasks and conducting activities mostly outdoors. Contacts of a primary case within the same bubble were evaluated by nasopharyngeal RT-PCR. Secondary attack rates and effective reproduction number in summer schools(R*) were calculated.

RESULTS

Among the over 2000 repeatedly screened participants, 30children and 9adults were identified as primary cases. A total of 253 close contacts of these primary cases were studied (median 9 (IQR 5-10) for each primary case), among which twelve new cases (4.7%) were positive for SARS-CoV-2. The R* was 0.3, whereas the contemporary rate in the general population from the same areas in Barcelona was 1.9.

CONCLUSIONS

The transmission rate of SARS-CoV-2 infection among children attending school-like facilities under strict prevention measures was lower than that reported for the general population. This suggests that under preventive measures schools are unlikely amplifiers of SARS-CoV-2 transmission and supports current recommendations for school opening.

Model-based evaluation of school- and non-school-related measures to control the COVID-19 pandemic

The role of school-based contacts in the epidemiology of SARS-CoV-2 is incompletely understood. We use an age-structured transmission model fitted to age-specific seroprevalence and hospital admission data to assess the effects of school-based measures at different time points during the COVID-19 pandemic in the Netherlands. Our analyses suggest that the impact of measures reducing school-based contacts depends on the remaining opportunities to reduce non-school-based contacts. If opportunities to reduce the effective reproduction number (Re) with non-school-based measures are exhausted or undesired and Re is still close to 1, the additional benefit of school-based measures may be considerable, particularly among older school children. As two examples, we demonstrate that keeping schools closed after the summer holidays in 2020, in the absence of other measures, would not have prevented the second pandemic wave in autumn 2020 but closing schools in November 2020 could have reduced Re below 1, with unchanged non-school-based contacts.

Timeliness of immunisations in preterm infants in the Netherlands

BACKGROUND

In the Netherlands, preterm infants receive the immunisations at the same chronological age as recommended for term infants without correction for gestational age (GA). The aim of this paper was to describe the timeliness of the routine Dutch national immunisation schedule in preterm infants in their first year of life and to evaluate possible determinants of delay.

METHODS

Preterm infants were prospectively recruited between October 2015 and October 2017 and stratified according to GA (<28, 28-32 and 32-36 weeks). Data from the baseline parental questionnaire, monthly parental questionnaires and medical records were used to determine the immunisation age and proportion of infants timely receiving the first immunisations (between 42 and 63 days). Results were compared between the GA and birth weight (BW) groups. Determinants associated with timeliness of immunisation were studied by multivariate logistic regression analysis.

RESULTS

Timely start of immunisation occurs in 60.5% of preterm infants in the Netherlands. The proportion of infants receiving the first immunisation on time was lowest for the group with GA <28 weeks (37%). The mean age of the first immunisation across all GA groups was 62.7 days (range 33-118) and differed significantly between GA group <28 weeks and the other two GA groups of 28-32 and 32-36 weeks (p < 0.001). Similar results were seen when stratified by BW. Multivariate analysis showed that low socioeconomic status (SES) and prolonged hospitalisation beyond 37 weeks each negatively influenced timeliness of the first immunisation.

CONCLUSION

These findings indicate that start of immunisations was often delayed in prematures and differs for different GA groups, being lowest (37%) in infants <28 weeks GA. Lower SES and prolonged hospital stay beyond 37 weeks GA are important determinants of timeliness. Efforts to improve timeliness should focus most on counselling parents in lower SES.

Shift Work and Respiratory Infections in Health-Care Workers

Recently, there has been interest in whether shift work may enhance susceptibility to infection. Our aim was to determine whether shift workers in the health-care field have a higher incidence, duration, and/or severity of influenza-like illness (ILI) and acute respiratory infection (ARI) than non–shift workers. From September 2016 to June 2017, 501 rotating and/or night-shift workers and 88 non–shift workers from the Klokwerk+ Study (the Netherlands, 2016–2017) registered the occurrence of ILI/ARI symptoms daily using a smartphone application. The incidence rate of ILI/ARI (defined as ≥2 symptoms on the same day/≥1 symptom on 2 consecutive days), the mean duration of each episode, and the incidence rate of severe episodes were compared between shift workers and non–shift workers using negative binomial regression and linear mixed-model analysis. In total, participants completed 110,347 diaries. Shift workers’ incidence rate of ILI/ARI was 1.20 (95% confidence interval (CI): 1.01, 1.43) times higher than that of non–shift workers, and for severe ILI/ARI episodes, shift workers’ incidence rate was 1.22 (95% CI: 1.01, 1.49) times higher. The mean duration of an ILI/ARI episode did not differ (ratio between means = 1.02, 95% CI: 0.87, 1.19). In conclusion, shift workers in health care had more ILI/ARI episodes and more severe ILI/ARI episodes than non–shift workers, but with a similar duration. Insight into underlying mechanisms connecting shift work and infection susceptibility will contribute to the design of preventive initiatives.

Clinical Course and Management of Dengue in Children Admitted to Hospital; A 5 Years Prospective Cohort Study in Jakarta, Indonesia

BACKGROUND

Dengue incidence is rising globally which was estimated 100 million per year, whereas in Indonesia was estimated 7.5 million per year. Dengue clinical course varies from mild dengue fever (DF) to dengue hemorrhagic fever (DHF) or dengue shock syndrome (DSS). Patients, clinicians and care facilities would benefit if reliable predictors can determine at admission which cases with clinically suspected dengue will progress to DHF or DSS.

METHODS

From 2009 through 2013, a cohort of 496 children admitted with clinically suspected dengue at a tertiary care hospital in Jakarta, Indonesia in, was followed until discharge. We evaluated the clinical course and disease outcome of admitted patients, and estimated the burden of dengue cases hospitalized over time.

RESULTS

Of all 496 children, 185 (37%) were classified at admission as DF, 158 (32%) as DHF and 153 (31%) as DSS. Of DF patients, 52 (28%) progressed to DHF or DSS, 10 (5%) had other viral diseases. Of DHF patients, 9(6%) progressed to DSS. No patients died. Of 33 routinely collected parameters at admission, duration of fever ≤ 4 days was the only significant predictor of disease progression (p= 0.01). Between 2009 and 2013, annual dengue admissions declined, while the distribution of disease severity remained stable.

CONCLUSIONS

Almost a third of children admitted to tertiary care with clinically suspected DF progress to DHF or DSS. Among routinely collected parameters at admission, only fever duration was significantly associated with clinical progression, emphasizing the unpredictability of dengue disease course from parameters currently routinely collected.

Updated cost-effectiveness and risk-benefit analysis of two infant rotavirus vaccination strategies in a high-income, low-endemic setting

BACKGROUND AND OBJECTIVE

Since 2013, a biennial rotavirus pattern has emerged in the Netherlands with alternating high and low endemic years and a nearly 50% reduction in rotavirus hospitalization rates overall, while infant rotavirus vaccination has remained below 1% throughout. As the rotavirus vaccination cost-effectiveness and risk-benefit ratio in high-income settings is highly influenced by the total rotavirus disease burden, we re-evaluated two infant vaccination strategies, taking into account this recent change in rotavirus epidemiology.

METHODS

We used updated rotavirus disease burden estimates derived from (active) surveillance to evaluate (1) a targeted strategy with selective vaccination of infants with medical risk conditions (prematurity, low birth weight, or congenital conditions) and (2) universal vaccination including all infants. In addition, we added herd protection as well as vaccine-induced intussusception risk to our previous cost-effectiveness model. An age- and risk-group structured, discrete-time event, stochastic multi-cohort model of the Dutch pediatric population was used to estimate the costs and effects of each vaccination strategy.

RESULTS

The targeted vaccination was cost-saving under all scenarios tested from both the healthcare payer and societal perspective at rotavirus vaccine market prices (€135/child). The cost-effectiveness ratio for universal vaccination was €51,277 at the assumed vaccine price of €75/child, using a societal perspective and 3% discount rates. Universal vaccination became cost-neutral at €32/child. At an assumed vaccine-induced intussusception rate of 1/50,000, an estimated 1707 hospitalizations and 21 fatal rotavirus cases were averted by targeted vaccination per vaccine-induced intussusception case. Applying universal vaccination, an additional 571 hospitalizations and <  1 additional rotavirus death were averted in healthy children per vaccine-induced intussusception case.

CONCLUSION

While universal infant rotavirus vaccination results in the highest reductions in the population burden of rotavirus, targeted vaccination should be considered as a cost-saving alternative with a favorable risk-benefit ratio for high-income settings where universal implementation is unfeasible because of budget restrictions, low rotavirus endemicity, and/or public acceptance.

Report of the 5th European expert meeting on rotavirus vaccination (EEROVAC)

The Fifth European Expert Meeting on Rotavirus Vaccination was convened in Utrecht, The Netherlands, in March 2017. The 2-day meeting included invited lectures as well as original oral and poster presentations and brought together experts from 21 countries. Summary findings of the meeting include: Rotavirus vaccination programmes in Europe have resulted in reductions of 60–90% in rotavirus outpatient visits and hospitalizations. Long term trends indicate this impact is sustained over the years. Herd effects, protecting unvaccinated children and neonates too young to be vaccinated have been observed in many European countries. Early evidence now also suggests that rotavirus vaccination may be instrumental in the prevention of celiac disease. Special attention should be given to preterm infants, who may age out of the vaccination window before hospital discharge and to HIV infected children who are at increased risk of severe rotavirus AGE. There is a small but increased risk of IS following rotavirus vaccination and parents should therefore be informed about possible signs and symptoms of IS. New insights in rotavirus genetic susceptibility and interactions with microbiome may open opportunities for interventions to improve protection by vaccination, in particular in LMIC. The development of several novel rotavirus vaccines discussed at the meeting is also promising in this respect.

Impact of Early-Onset Acute Otitis Media on Multiple Recurrences and Associated Health Care Use

OBJECTIVE

To quantify the critical age period of first episode of acute otitis media (AOM) and its consequences for AOM recurrences and AOM health care use.

STUDY DESIGN

Children enrolled in the Wheezing-Illnesses-STudy-LEidsche-Rijn cohort with at least 1 episode of AOM documented in their primary care health record before 2 years of age were followed until 6 years of age. Data on episodes of AOM and associated primary care consultations, antibiotic prescriptions, and specialist referrals were retrieved. Regression models assessed the presence and shape of the associations between age of first AOM and subsequent episodes of AOM and health care use.

RESULTS

A total of 796 of 2026 children (39%) experienced a first AOM before 2 years of age. Each month decrease in age at first AOM in the first 2 years of life increased the risk of developing recurrent AOM (≥3 AOM episodes in 6 months or ≥ 4 in 1 year) linearly by 6% (adjusted risk ratio: 1.06; 95% CI: 1.02-1.10). For first AOM occurring before 9 months, the cumulative 6-year primary care consultation rate increased by 8% (adjusted incidence rate ratio: 1.08; 95% CI: 1.03-1.15) and the associated specialist referral increased by 16% (adjusted risk ratio: 1.16; 95% CI: 1.07-1.27) for each month decrease in age. No associations were found between age at first AOM and total AOM episodes or antibiotic prescriptions.

CONCLUSIONS

The association between earlier age of first AOM and recurrent AOM as well as total health care use during childhood is particularly strong before 9 months of age.

First-year Daycare and Incidence of Acute Gastroenteritis

BACKGROUND

Daycare attendance has been associated with increased acute gastroenteritis (AGE) incidence in the first years of life. We investigated the effects of first-year daycare attendance on AGE incidence and primary care contact rate up to age 6 years.

METHODS

Children enrolled in the Wheezing Illnesses Study Leidsche Rijn cohort were managed until age 6 years. Data on primary care diagnosed AGE episodes and number of associated contacts per episode were collected from health records. Children were categorized according to first year daycare attendance and age-month at entry when applicable. Generalized estimating equations were used to assess associations between first-year daycare and AGE incidence or primary care contact rate.

RESULTS

A total of 1344 out of 2220 children (83%) attended daycare before age 1 year. Overall, the 6-year primary care AGE incidence rate (IR) among first-year daycare attendees and nonattendees was comparable (IR: 12.2/100 vs 13.3/100 child-years). First-year daycare attendees had a higher AGE incidence during the first year (IRR: 1.13; 95% confidence interval: 1.06-1.21) and lower during the third to sixth year of age compared with nonattendees (P < .001). The daycare-associated increase in AGE incidence was most pronounced during the first 12 months after enrollment into daycare and demonstrated clear seasonality. A similar pattern was observed for primary care contact rate per AGE episode.

CONCLUSIONS

First-year daycare attendance advances the timing of AGE infections, resulting in increased AGE disease burden in the first year and relative protection thereafter. Protection against AGE infection persists at least up to age 6 years. Future studies should address whether this protective effect persists during later childhood.

Exceptionally low rotavirus incidence in the Netherlands in 2013/14 in the absence of rotavirus vaccination

An unexpected drop in rotavirus (RV) detections was observed in the Netherlands in 2014, without RV vaccination. The estimated decrease in RV detections and gastroenteritis consultations in under five year-olds, in January-April 2014, compared to the same months in previous years, was 72% and 36%, respectively. The low birth rate, mild winter, high RV incidence in the previous year and the introduction of RV vaccination in neighbouring countries may have contributed to this decrease.

Impact of early daycare on healthcare resource use related to upper respiratory tract infections during childhood: prospective WHISTLER cohort study

BACKGROUND

Daycare attendance is an established risk factor for upper respiratory tract infections (URTI) and acute otitis media (AOM). Whether this results in higher use of healthcare resources during childhood remains unknown. We aim to assess the effect of first year daycare attendance on the timing and use of healthcare resources for URTI and AOM episodes during early childhood.

METHODS

In the Wheezing-Illnesses-STudy-LEidsche-Rijn birth cohort, 2,217 children were prospectively followed up to age six years. Children were categorized according to first-year daycare attendance (yes versus no) and age at entry when applicable (age 0 to 2 months, 3 to 5 months and 6 to 12 months). Information on general practitioner (GP) diagnosed URTI and AOM, GP consultations, antibiotic prescriptions and specialist referral was collected from medical records. Daycare attendance was recorded by monthly questionnaires during the first year of life.

RESULTS

First-year daycare attendees and non-attendees had similar total six-year rates of GP-diagnosed URTI and AOM episodes (59/100 child-years, 95% confidence interval 57 to 61 versus 56/100 child-years, 53 to 59). Daycare attendees had more GP-diagnosed URTI and AOM episodes before the age of one year and fewer beyond the age of four years than non-attendees (Pinteraction <0.001). Daycare attendees had higher total six-year rates for GP consultation (adjusted rate ratio 1.15, 1.00 to 1.31) and higher risk for specialist referrals (hazard ratio: 1.43, 1.01 to 2.03). The number of antibiotic prescriptions in the first six years of life was only significantly increased among children who entered daycare between six to twelve months of age (rate ratio 1.32, 1.04 to 1.67). This subgroup of child-care attendees also had the highest overall URTI and AOM incidence rates, GP consultation rates and risk for specialist referral.

CONCLUSIONS

Children who enter daycare in the first year of life, have URTI and AOM at an earlier age, leading to higher use of healthcare resources compared to non-attendees, especially when entering daycare between six to twelve months. These findings emphasize the need for improved prevention strategies in daycare facilities to lower infection rates at the early ages.

High detection rates of enteropathogens in asymptomatic children attending day care

Background

Gastroenteritis morbidity is high among children under the age of four, especially amongst those who attend day care.

Objective

To determine the prevalence of a range of enteropathogens in the intestinal flora of children attending day care and to relate their occurrence with characteristics of the sampled child and the sampling season.

Methods

We performed three years of enteropathogen surveillance in a network of 29 child day care centers in the Netherlands. The centers were instructed to take one fecal sample from ten randomly chosen children each month, regardless of gastrointestinal symptoms at time of sampling. All samples were analyzed for the molecular detection of 16 enteropathogenic bacteria, parasites and viruses by real-time multiplex PCR.

Results

Enteropathogens were detected in 78.0% of the 5197 fecal samples. Of the total, 95.4% of samples were obtained from children who had no gastroenteritis symptoms at time of sampling. Bacterial enteropathogens were detected most often (most prevalent EPEC, 19.9%), followed by parasitic enteropathogens (most prevalent: D. fragilis, 22.1%) and viral enteropathogens (most prevalent: norovirus, 9.5%). 4.6% of samples related to children that experienced symptoms of gastroenteritis at time of sampling. Only rotavirus and norovirus were significantly associated with gastroenteritis among day care attendees.

Conclusions

Our study indicates that asymptomatic infections with enteropathogens in day care attendees are not a rare event and that gastroenteritis caused by infections with these enteropathogens is only one expression of their presence.

Targeted rotavirus vaccination of high-risk infants; a low cost and highly cost-effective alternative to universal vaccination

BACKGROUND

The cost-effectiveness of universal rotavirus (RV) vaccination is controversial in developed countries. As a result, RV vaccination programs do not currently exist in most European countries. Hospitalization is the main driver of RV disease costs, and prematurity, low birth weight (LBW) and underlying medical conditions have been associated with RV hospitalization and complications. We investigated the cost-effectiveness of targeted RV vaccination of high-risk infants and universal RV vaccination versus no vaccination.

METHODS

Disease burden, mortality and healthcare costs of RV hospitalization for children with and without prematurity, LBW and congenital pathology were quantified in two hospital-based observational studies in the Netherlands. Cost-effectiveness analysis was based on an age-structured stochastic multi-cohort model of the Dutch population comparing universal RV vaccination and targeted vaccination of high-risk infants to no vaccination. The primary endpoint was the incremental cost-effectiveness ratio (ICER), with a threshold of €35,000/quality-adjusted life year (QALY) from the healthcare provider perspective. Sensitivity analyses included vaccine price and coverage, herd-immunity and QALY losses.

RESULTS

A total of 936 children with RV infection were included. Prematurity, LBW and congenital pathology were associated with increased risks of RV hospitalization (relative risks (RR) ranging from 1.6 to 4.4), ICU admission (RR ranging from 4.2 to 7.9), prolonged hospital stay (1.5 to 3.0 excess days) and higher healthcare costs (€648 to €1,533 excess costs). Seven children succumbed due to RV complications, all belonging to the high-risk population. Targeted RV vaccination was highly cost-effective and potentially cost-saving from the healthcare provider perspective with ICERs below €20,000/QALY in all scenarios with total (undiscounted) annual healthcare costs between -€0.1 and €0.5 million/year. Results were most sensitive to mortality rates, but targeted vaccination remained highly cost-effective up to reductions of 90% compared to observed mortality. Universal RV vaccination was not considered cost-effective (mean ICER: €60,200/QALY) unless herd-immunity and caretaker QALY losses were included and vaccine prices were €60 at most (mean ICER: €21,309/QALY).

CONCLUSION

We recommend targeted RV vaccination for high-risk infants in developed countries.

Nosocomial rotavirus infections: a meta-analysis

BACKGROUND AND OBJECTIVES

Nosocomial rotavirus (nRV) infections represent an important part of rotavirus (RV)-associated morbidity. The incidence of nRV influences the estimated total RV disease burden, an important determinant of cost-effectiveness of RV vaccination programs. Our aim is to summarize the existing evidence and produce reliable estimates of nRV incidence, in pediatric settings in Europe and North America.

METHODS

We searched electronic databases for studies on nRV incidence among pediatric inpatients. To ascertain complete case reporting, only studies describing active nRV surveillance in their methodology were included. Random effects meta-analysis was performed. Meta-regression was used to obtain results adjusted for important study characteristics.

RESULTS

Twenty surveillance studies met the quality criteria for inclusion. The pooled unadjusted nRV incidence was 2.9 per 100 hospitalizations (95% confidence interval [CI]: 1.6-4.4). Incidence was significantly influenced by studies' seasonality-months (RV epidemic season only or year-round) and the age range of included patients. Highest nRV incidence was found for children <2 years of age, hospitalized during the epidemic months (8.1/100 hospitalizations; 95% CI: 6.4-9.9). The adjusted year-round nRV incidence estimate without age restriction was 0.4/100 hospitalizations (95% CI: 0.1-2.1) and 0.7 (95% CI: 0.0-1.8) for children <5 years of age.

CONCLUSIONS

This is the first meta-analysis to summarize results of surveillance studies on nRV incidence. nRV is an important problem among hospitalized infants during the winter months. The lower season and age-adjusted nRV incidence estimate seems more appropriate for application in population-based burden of disease analysis.