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.

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.

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.