Socioeconomic inequalities in COVID-19 infection and vaccine uptake among children and adolescents in Catalonia, Spain (preprint)

IMPORTANCE The relationship between socioeconomic deprivation and COVID-19 infection and vaccination among children and adolescents remains unclear. OBJECTIVE To investigate the association between deprivation and COVID-19 vaccine uptake and infection among children and adolescents before and after the vaccination rollout in Catalonia, Spain. DESIGN AND SETTING Population-based cohort study using primary care electronic health records from the Information System for Research in Primary Care. Individuals were followed 3 months before the start of the vaccination campaign in Spain and 3 months after the vaccination rollout among adolescents and children. PARTICIPANTS Children (5-11 years) and adolescents (12-15 years) with at least 1 year of prior history observation available and without missing deprivation data. EXPOSURE Deprivation, assessed using an ecological socioeconomic deprivation index (SDI) score for census tract urban areas and categorized into quintiles. MAIN OUTCOMES AND MEASURES COVID-19 infection and COVID-19 vaccination. For each outcome, we calculated cumulative incidence and crude Cox proportional-hazard models by SDI quintiles, and estimated hazard ratios (HRs) of COVID-19 infection and vaccine uptake relative to the least deprived quintile, Q1. RESULTS Before COVID-19 vaccination rollout, 290,625 children and 179,685 adolescents were analyzed. Increased HR of deprivation was associated with a higher risk of COVID-19 infection in both children (Q5: 1.55 [95% CI, 1.47 - 1.63]) and adolescents (Q5: 1.36 [95% CI, 1.29 - 1.43]). After the rollout, this pattern changed among children, with lower risk of infection in more deprived areas (Q5: 0.62 [95% CI, 0.61 - 0.64]). Vaccine uptake was higher among adolescents (72.6%) than children (44.8%), but in both age groups, non-vaccination was more common among those living in more deprived areas (39.3% and 74.6% in Q1 vs. 26.5% and 66.9% in Q5 among children and adolescents, respectively). CONCLUSIONS AND RELEVANCE In this cohort study, children and adolescents living in deprived areas were at higher risk of COVID-19 non-vaccination. Socioeconomic disparities in COVID-19 infection were also evident before vaccine rollout, with a higher infection risk in deprived areas across age groups. Our findings suggest that changes in the association between deprivation and infections among children after the vaccine rollout were likely due to testing disparities.

Unraveling the Effects of the COVID-19 Pandemic on the Burden of Respiratory Syncytial Virus in a Tertiary Hospital in Catalonia, Spain: Season 2022-2023 Analysis (preprint)

Purpose: Respiratory Syncytial Virus (RSV) associated infections have historically been the cause of seasonal paediatric hospital departments’ saturation. During the COVID-19 pandemic, the community incidence of RSV was reduced, thus the hospital burden. The last RSV season broke out in early October 2022, 4-6 weeks earlier than in pre-pandemic years, and was thought to be the most demanding to date. Our aim was to assess the burden of RSV-related hospitalizations on a referral hospital (Catalonia, Spain) during the pre-pandemic years and the most recent 2022-2023 season. Methods: We analysed the paediatric hospital and intensive care (PICU) admissions data (January 2016 – January 2023) of a tertiary referral hospital in Catalonia, Spain. All-cause pediatric admissions, admissions related to confirmed RSV infections, and occupancy-related variables were collected. Results and conclusion: RSV-related hospitalizations incidence was lower during the pandemic years, particularly in 2020. The majority of RSV cases within an epidemic peak primarily affected children ≤3 months. Although the number of daily admissions during the last RSV 2022-2023 season was not higher than in the pre-pandemic years, the mean occupancy of the hospital was significantly higher (p= 0.04) due to a longer period of days with more than 20 RSV infected children inpatients per day.

Syndromic surveillance as a predictive tool for health-related school absences in COVID-19 Sentinel Schools in Catalonia, Spain. (preprint)

Monitoring influenza-like illness through syndromic surveillance could be an important strategy in the COVID-19 emergence scenario. The study aims to implement syndromic surveillance for children aged 6-11 years in COVID-19 sentinel schools in Catalonia. Data collection was made by self-applied survey to collect daily health status and symptoms. We proceed logistic mixed models and a Latent Class Analysis to investigate associations with syndromes and school absence. Were enrolled 135 students (2163 person-days) that filled 1536 surveys and 60 participants reported illness (29.52 by 100 person/day) and registered 189 absence events, 62 of them (32.8%) related to health reasons. Subgroups of influenza-like illness were founded such as a significantly and positively association with school absences. The findings of this study can be applied to the detection of health events, and association with school absences, offering an opportunity for quick action, or simply for monitoring and understanding the students' health situation.

Multisystem Inflammatory Syndrome in Children and SARS-CoV-2 variants: a two-year ambispective multicentric cohort study in Catalonia, Spain. (preprint)

Purpose Multisystem inflammatory syndrome in children (MIS-C) is a rare but severe disease temporarily related to SARS-CoV-2. We aimed to describe the epidemiological, clinical and laboratory findings of all the MIS-C cases diagnosed in children < 18 years-old in Catalonia (Spain) to study their trend throughout the pandemic.Methods Multicenter ambispective observational cohort study (April 2020-April 2022). Data were obtained from the COVID-19 Catalan surveillance system and from all the hospitals in Catalonia. We analyzed MIS-C cases regarding SARS-CoV-2 variants for demographics, symptoms, severity, monthly MIS-C incidence, ratio between MIS-C and accumulated COVID-19 cases, and associated rate ratios (RR).Results Among 555,848 SARS-CoV-2 infections, 152 children were diagnosed with MIS-C. Monthly MIS-C incidence was 4.1 (95%CI: 3.4–4.8) per 1,000,000 people, and 273 (95%CI: 230–316) per 1,000,000 SARS-CoV-2 infections (i.e., one case per 3,700 SARS-CoV-2 infections). During the Omicron period, MIS-C RR was 8.2 (95%CI: 5.7–11.7) per 1,000,000 SARS-CoV-2 infections, significantly lower (p < 0.001) than for previous variant periods, in all age groups. Median [IQR] age of MIS-C was 8 [4–11] years, 62.5% male, and 80.2% without comorbidities. Common symptoms were gastrointestinal findings (88.2%) and fever > 39oC (81.6%), nearly 40% had an abnormal echocardiography and 7% coronary aneurysm. Clinical manifestations and laboratory data were not different throughout the variant periods (p > 0.05).Conclusions The rate ratio between MIS-C cases and SARS-CoV-2 infections was significantly lower in the Omicron period for all the age groups, including those not vaccinated, suggesting that the variant could be the main factor for this shift in the MISC trend. Regardless of variant type, the patients had similar phenotypes and severity throughout the pandemic.

Comparison of pneumonia features in children caused by SARS-CoV-2 and other viral respiratory pathogens. (preprint)

Pneumonia is a frequent manifestation of COVID-19 in hospitalized children. Methods The study involved 80 hospitals in the SARS-CoV-2 Spanish Pediatric National Cohort. Participants were children <18 years, hospitalized with SARS-CoV-2 community-acquired pneumonia (CAP). We compared the clinical characteristics of SARS-CoV-2-associated CAP with CAP due to other viral etiologies from 2012 to 2019. Results In total, 151 children with SARS-CoV-2-associated CAP and 138 with other viral CAP included. Main clinical features of SARS-CoV-2-associated CAP were cough 117/151(77%), fever 115/151(76%) and dyspnea 63/151(46%); 22/151(15%) patients were admitted to a pediatric intensive care unit (PICU), and 5/151(3%) patients died. Lymphopenia was found in 63/147(43%) patients. Chest X-ray revealed condensation (64/151[42%]) and other infiltrates (87/151[58%]). Compared with CAP from other viral pathogens, COVID-19 patients were older (8 vs.1 year; odds ratio [OR] 1.42 [95% confidence interval, CI 1.23;1.42]), with lower CRP levels (23 vs.48 mg/L; OR 1 [95%CI 0.99;1]), less wheezing (17 vs.53%; OR 0.18 [95%CI 0.11;0.31]) and greater need of mechanical ventilation, MV (7 vs.0.7%, OR 10.8 [95%CI 1.3;85). Patients with non-SARS-CoV-2-associated CAP had a greater need for oxygen therapy (77 vs.44%, OR 0.24 [95%CI 0.14;0.40]). There were no differences in the use of CPAP or HVF or PICU admission between groups. Conclusion SARS-CoV-2-associated CAP in children presents differently to other virus-associated CAP: children are older and rarely have wheezing or high CRP levels; they need less oxygen but more CPAP or MV. However, several features overlap, and differentiating the etiology may be difficult. The overall prognosis is good.

The Spectrum of COVID-19 in Children in Spain (preprint)

Background: We aimed to identify the spectrum of disease in children with COVID-19, and the risk factors for admission in paediatric intensive care units (PICUs). Methods: : We conducted a multicentre, prospective study of children with SARS-CoV-2 infection in 76 Spanish hospitals. We included children with COVID-19 or multi-inflammatory syndrome (MIS-C) younger than 18 years old, attended during the first year of the pandemic. Results: We enrolled 1 200 children. A total of 666 (55.5%) were hospitalized, and 123 (18.4%) required admission to PICU. Most frequent major clinical syndromes in the cohort were: mild syndrome (including upper respiratory tract infection and flu-like syndrome, skin or mucosae problems and asymptomatic), 44.8%; bronchopulmonary syndrome (including pneumonia, bronchitis and asthma flare), 18.5%; fever without a source, 16.2%; MIS-C, 10.6%; and gastrointestinal syndrome, 10%. In hospitalized children, the proportions were: 28.5%, 25.7%, 16.5%, 19.1% and 10.2%, respectively. Risk factors associated with PICU admission were MIS-C (odds ratio [OR]: 37.5,95% CI 22.7 to 57.8), moderate or severe liver disease (OR: 9,95% CI 1.6 to 47.6), chronic cardiac disease (OR: 4.8,95% CI 1.8 to 13) and asthma or recurrent wheezing (OR: 2.8,95% CI 1.3 to 5.8). However, asthmatic children were admitted into the PICU due to MIS-C or pneumonia, not due to asthma flare. Conclusion: Hospitalized children with COVID-19 usually present as one of five major clinical phenotypes of decreasing severity. Risk factors for PICU include MIS-C, elevation of inflammation biomarkers, asthma, moderate or severe liver disease and cardiac disease.

Epidemiological dynamics of the incidence of COVID-19 in children and the relationship with the opening of schools in Catalonia (Spain) (preprint)

Here we analyse the epidemiological trend of the incidence of COVID-19 in children in Catalonia (Spain) during the first 20 weeks of the 2020-2021 school year. This study demonstrates that while schools were open the incidence rate among children remained significantly lower than in general population, despite a greater diagnostic effort in children. These results suggest that schools have not played a significant role in the SARS-CoV-2 dissemination in Catalonia.

Fever without source as the first manifestation of SARS-CoV-2 infection in infants less than 90 days old. (preprint)

Fever without source (FWS) in infants is a frequent cause of consultation at the emergency department and the emergence of SARS-CoV-2 could affect the approach to those infants. The aim of this study is to define the clinical characteristics and rates of bacterial coinfections of infants < 90 days with FWS as the first manifestation of SARS-CoV-2 infection. This is a cross-sectional study of infants under 90 days of age with FWS and positive SARS-CoV2 PCR in nasopharyngeal swab/aspirate, attended at the emergency departments of 49 Spanish hospitals (EPICO-AEP cohort) from March 1st to June 26th, 2020. Three hundred and thirty-three  children with COVID-19 were included in EPICO-AEP. A total of 67/336 (20%) were infants less than 90 days old, and 27/67(40%) presented with FWS. Blood cultures were performed in 24/27(89%) and were negative in all but one (4%) who presented a Streptococcus mitis bacteremia. Urine culture was performed in 26/27(97%) children and was negative in all, except in two (7%) patients. Lumbar puncture was performed in 6/27(22%) cases, with no growth of bacteria. Two children had bacterial coinfections: 1 had UTI and bacteremia, and 1 had UTI. C-reactive was protein over 20 mg/L in two children (one with bacterial coinfection), and procalcitonin was normal in all. One child was admitted to the Pediatric Intensive Care Unit because of apnea episodes. No patients died. Conclusion: FWS was frequent in infants under 90 days of age with SARS-CoV-2 infection. Standardized markers to rule out bacterial infections remain useful in this population, and the outcome is generally good.

Potential Role of Children in the Household Transmission of SARS-CoV-2 Infection in Catalonia (Spain) (preprint)

We analyzed the characteristics of the Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) infected children during lock-down period in Catalonia (Spain), and their transmission role within the households. Among 295 traced household contacts of 89 pediatric patients, children were classified as final index cases in only 3.4% of the traced homes.