Multisystem inflammatory syndrome in children and SARS-CoV-2 variants: a two-year ambispective multicentric cohort study in Catalonia, Spain.

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 MIS-C cases diagnosed in children < 18 years old in Catalonia (Spain) to study their trend throughout the pandemic. This was a multicenter ambispective observational cohort study (April 2020-April 2022). Data were obtained from the COVID-19 Catalan surveillance system and from all 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). Among 555,848 SARS-CoV-2 infections, 152 children were diagnosed with MIS-C. The 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, the MIS-C RR was 8.2 (95% CI: 5.7-11.7) per 1,000,000 SARS-CoV-2 infections, which was significantly lower (p < 0.001) than that for previous variant periods in all age groups. The 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 > 39 °C (81.6%); nearly 40% had an abnormal echocardiography, and 7% had coronary aneurysm. Clinical manifestations and laboratory data were not different throughout the variant periods (p > 0.05).  Conclusion: The RR between MIS-C cases and SARS-CoV-2 infections was significantly lower in the Omicron period for all 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. What is Known: • Before our study, only two publications investigated the incidence of MIS-C regarding SARS-CoV-2 variants in Europe, one from Southeast England and another from Denmark. What is New: • To our knowledge, this is the first study investigating MIS-C incidence in Southern Europe, with the ability to recruit all MIS-C cases in a determined area and analyze the rate ratio for MIS-C among SARS-CoV-2 infections throughout variant periods. • We found a lower rate ratio of MISC/infections with SARS-CoV-2 in the Omicron period for all age groups, including those not eligible for vaccination, suggesting that the variant could be the main factor for this shift in the MISC trend.

Cancer diagnosis in primary care after second pandemic year in Catalonia: a time-series analysis of primary care electronic health records covering about 5 million people.

BACKGROUND: During the COVID-19 pandemic, the incidence of chronic disease had drastically been reduced due to health care interruptions. The aim of this study is to analyse cancer diagnosis during the last 2 years of the COVID-19 pandemic. METHODS: Time-series study of cancer diagnoses recorded in primary care settings, using data from the primary care electronic health records from January 2014 to December 2021. We obtained the expected monthly rate per 100,000 inhabitants using a time regression adjusted by trend and seasonality. We additionally compared rates of cancer diagnoses in 2019 with those of 2020 and 2021 using the t-test. We performed the analysis globally, by sex and by type of cancer. RESULTS: In 2020, the rate of cancer diagnoses had reduced by -21% compared to 2019 (P < 0.05). Greater reductions were observed during the lockdown in early 2020 (>40%) and with some types of cancers, especially prostate and skin cancers (-29.6% and -26.9%, respectively, P < 0.05). Lung cancers presented statistically non-significant reductions in both years. Cancer diagnosis returned to expected around March 2021, and the rate in 2021 was similar to that of 2019 (overall difference of 0.21%, P = 0.967). However, an 11% reduction was still found when comparing the pandemic months of 2020-2021 with pre-pandemic months. CONCLUSIONS: Although primary care cancer diagnoses in 2021 have returned to pre-pandemic levels, missing diagnoses during the last 2 years have not been fully recovered.

Divergences on expected pneumonia cases during the COVID-19 epidemic in Catalonia: a time-series analysis of primary care electronic health records covering about 6 million people.

BACKGROUND: Pneumonia is one of the complications of COVID-19. Primary care electronic health records (EHR) have shown the utility as a surveillance system. We therefore analyse the trends of pneumonia during two waves of COVID-19 pandemic in order to use it as a clinical surveillance system and an early indicator of severity. METHODS: Time series analysis of pneumonia cases, from January 2014 to December 2020. We collected pneumonia diagnoses from primary care EHR, a software system covering > 6 million people in Catalonia (Spain). We compared the trend of pneumonia in the season 2019-2020 with that in the previous years. We estimated the expected pneumonia cases with data from 2014 to 2018 using a time series regression adjusted by seasonality and influenza epidemics. RESULTS: Between 4 March and 5 May 2020, 11,704 excess pneumonia cases (95% CI: 9909 to 13,498) were identified. Previously, we identified an excess from January to March 2020 in the population older than 15 years of 20%. We observed another excess pneumonia period from 22 october to 15 november of 1377 excess cases (95% CI: 665 to 2089). In contrast, we observed two great periods with reductions of pneumonia cases in children, accounting for 131 days and 3534 less pneumonia cases (95% CI, 1005 to 6064) from March to July; and 54 days and 1960 less pneumonia cases (95% CI 917 to 3002) from October to December. CONCLUSIONS: Diagnoses of pneumonia from the EHR could be used as an early and low cost surveillance system to monitor the spread of COVID-19.

Influence of organization and demographic characteristics of primary care practices on continuity of care: analysis of a retrospective cohort from 287 primary care practices covering about 6 million people in Catalonia.

BACKGROUND: There is evidence that an ongoing patient-physician relationship is associated with improved health outcomes and more efficient health systems. The main objective of this study is to describe the continuity of care in primary healthcare in Catalonia (Spain) and to analyze whether the organization of primary care practices (PCP) or their patients' sociodemographic characteristics play a role in its continuity of care. METHODS: Four indices were used to measure continuity of care: Usual Provider Index (UPC), Modified Modified Continuity Index (MMCI), Continuity of Care Index (COC), and Sequential Continuity Index (SECON). The study was conducted on 287 PCP of the Catalan Institute of Health (Institut Català de la Salut-ICS). Each continuity of care index was calculated at the patient level (3.2 million patients and 35.5 million visits) and then aggregated at the PCP level. We adjusted linear regression models for each continuity index studied, considering the result of the index as an independent variable and demographic and organizational characteristics of the PCP as explanatory variables. Pearson correlation tests were used to compare the four continuity of care indices. RESULTS: Indices' results were: UPC: 70,5%; MMCI: 73%; COC: 53,7%; SECON: 60,5%. The continuity of care indices had the highest bivariate correlation with the percentage of appointments booked with an assigned health provider (VISUBA variable: the lower the value, the higher the visits without an assigned health provider, and thus an organization favoring immediate consultation). Its R2 ranged between 56 and 63%, depending on the index. The multivariate model which explained better the variability of continuity of care indices (from 49 to 56%) included the variables VISUBA and rurality with a direct relationship; while the variables primary care physician leave days and training practices showed an inverse relationship. CONCLUSION: Study results suggest that an organization of primary care favoring immediate consultation is related to a lower continuity of patient care.

Primary care in the time of COVID-19: monitoring the effect of the pandemic and the lockdown measures on 34 quality of care indicators calculated for 288 primary care practices covering about 6 million people in Catalonia.

BACKGROUND: To analyse the impact of the COVID-19 epidemic and the lockdown measures on the follow-up and control of chronic diseases in primary care. METHODS: Retrospective study in 288 primary care practices (PCP) of the Catalan Institute of Health. We analysed the results of 34 indicators of the Healthcare quality standard (EQA), comprising different types: treatment (4), follow-up (5), control (10), screening (7), vaccinations (4) and quaternary prevention (4). For each PCP, we calculated each indicator's percentage of change in February, March and April 2020 respective to the results of the previous month; and used the T-Student test for paired data to compare them with the percentage of change in the same month of the previous year. We defined indicators with a negative effect those with a greater negative change or a lesser positive change in 2020 in comparison to 2019; and indicators with a positive effect those with a greater positive change or a lesser negative change. RESULTS: We observed a negative effect on 85% of the EQA indicators in March and 68% in April. 90% of the control indicators had a negative effect, highlighting the control of LDL cholesterol with a reduction of - 2.69% (95%CI - 3.17% to - 2.23%) in March and - 3.41% (95%CI - 3.82% to - 3.01%) in April; and the control of blood pressure with a reduction of - 2.13% (95%CI - 2.34% to - 1.9%) and - 2.59% (95%CI - 2.8% to - 2.37%). The indicators with the greatest negative effect were those of screening, such as the indicator of diabetic foot screening with a negative effect of - 2.86% (95%CI - 3.33% to - 2.39%) and - 4.13% (95%CI - 4.55% to - 3.71%) in March and April, respectively. Only one vaccination indicator, adult Measles-Mumps-Rubella vaccine, had a negative effect in both months. Finally, among the indicators of quaternary prevention, we observed negative effects in March and April although in that case a lower inadequacy that means better clinical outcome. CONCLUSIONS: The COVID-19 epidemic and the lockdown measures have significantly reduced the results of the follow-up, control, screening and vaccination indicators for patients in primary care. On the other hand, the indicators for quaternary prevention have been strengthened and their results have improved.

Effectiveness of an intervention designed to optimize statins use: a primary prevention randomized clinical trial.

BACKGROUND: Although hypercholesterolemia is considered a cardiovascular risk factor, in isolation it is not necessarily sufficient cause for a cardiovascular event. To improve event prediction, cardiovascular risk calculators have been developed; the REGICOR calculator has been validated for use in our population. The objective of this project is to develop an intervention with general practitioners (GPs) and evaluate its impact on prescription adequacy of cholesterol-lowering drugs in primary prevention of cardiovascular disease and in controlling the costs associated with this disease. METHODS: This nonblinded, cluster-randomized clinical trial analyzes data from primary care electronic medical records (ECAP) and other databases. Inclusion criteria are patients aged 35 to 74 years with no known cardiovascular disease and a new prescription for cholesterol-lowering drugs during the 2-year study period. Dependent variables include the following: RETIRA, defined as new cholesterol-lowering drugs initiated during the year preceding the intervention, considered inadequate, and withdrawn during the study period; EVITA, defined as new cholesterol-lowering drugs initiated during the study period and considered inadequate; COST, defined as the total cost of inadequate new treatments prescribed; and REGISTER, defined as the recording of cardiovascular risk factors. Independent variables include the GP's quality-of-care indicators and randomly assigned study group (intervention vs control), patient demographics, and clinical variables. Aggregated descriptive analysis will be done at the GP level and multilevel analysis will be performed to estimate the intervention effect, adjusted for individual and GP variables. DISCUSSION: The study objective is to generate evidence about the effectiveness of implementing feedback information programs directed to GPs in the context of Primary Care. The goal is to improve the prescription adequacy of lipid-lowering therapies for primary prevention. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT01997671. November 28, 2013.

Sexually transmitted infections, the epidemic that persists after the COVID-19 pandemic: an analysis of the primary care electronic health records covering about 5 million people in Catalonia.

BACKGROUND: The aim of our study is to analyse the trends in the diagnosis of sexually transmitted infections (STIs) during the COVID-19 pandemic. METHODS: We conducted an observational retrospective population-based study using data from primary care electronic health records spanning from January 2016 to December 2022 (involving 5.1 million people older than 14 years). We described the daily number of new STI diagnoses from 2016 to 2022; as well as the monthly accumulation of new STI diagnoses for each year. We compared the monthly averages of new diagnoses in 2019, 2020, 2021 and 2022 using the T-test. Finally, we performed a segmented regression analysis of the daily number of STI diagnoses. RESULTS: We analysed 200,676 new STI diagnoses. The number of diagnoses abruptly decreased coinciding with the lockdown. Overall in 2020, we observed a reduction of 15%, with higher reductions for specific STIs such as gonorrhoea (-21%), chlamydia (-24%), and HIV (-31%) compared to 2019. Following this drastic drop, which was temporarily associated with the lockdown, we observed a rapid rebound. In 2021, the number of STI diagnoses was similar to that of 2019. Notably, we found a considerable increase in 2022, particularly for non-specific STI, which lack laboratory confirmation (67% increase). HIV was the only STI with a reduction of up to -38% in diagnoses at the end of 2022 compared to 2019. CONCLUSIONS: After a significant reduction in 2020, the number of STIs recorded in primary care rapidly rebounded, and the current trend is similar to that of 2019, except for HIV. These findings underscore the dynamic impact of the COVID-19 pandemic on STI diagnoses and highlight the importance of ongoing monitoring and public health interventions in the post-pandemic period.

Effectiveness of nirsevimab immunoprophylaxis against respiratory syncytial virus-related outcomes in hospital and primary care settings: a retrospective cohort study in infants in Catalonia (Spain).

BACKGROUND: In Catalonia, infants under 6 months old were eligible to receive nirsevimab, a novel monoclonal antibody against respiratory syncytial virus (RSV). We aimed to analyse nirsevimab's effectiveness across primary and hospital care outcomes. METHODS: Retrospective cohort study from 1 October 2023 to 31 January 2024, including all infants born between April and September 2023. We established two cohorts based on nirsevimab administration (immunised and non-immunised). We followed individuals until the earliest moment of an outcome-RSV infection, primary care attended bronchiolitis and pneumonia, hospital emergency visits due to bronchiolitis, hospital admission or intensive care unit (ICU) admission due to RSV bronchiolitis-death or the end of the study. We used the Kaplan-Meier estimator and fitted Cox regression models using a calendar time scale to estimate HRs and their 95% CIs. RESULTS: Among 26 525 infants, a dose of nirsevimab led to an adjusted HR for hospital admission due to RSV bronchiolitis of 0.124 (95% CI: 0.086 to 0.179) and an adjusted HR for ICU admission of 0.099 (95% CI: 0.041 to 0.237). Additionally, the adjusted HRs observed for emergency visits were 0.446 (95% CI: 0.385 to 0.516) and 0.393 (95% CI: 0.203 to 0.758) for viral pneumonia, 0.519 (95% CI: 0.467 to 0.576) for bronchiolitis attended in primary care and 0.311 (95% CI: 0.200 to 0.483) for RSV infection. CONCLUSION: We demonstrated nirsevimab's effectiveness with reductions of 87.6% and 90.1% in hospital and ICU admissions, respectively. These findings offer crucial guidance for public health authorities in implementing RSV immunisation campaigns.

Severity of Omicron Subvariants and Vaccine Impact in Catalonia, Spain.

In the current COVID-19 landscape dominated by Omicron subvariants, understanding the timing and efficacy of vaccination against emergent lineages is crucial for planning future vaccination campaigns, yet detailed studies stratified by subvariant, vaccination timing, and age groups are scarce. This retrospective study analyzed COVID-19 cases from December 2021 to January 2023 in Catalonia, Spain, focusing on vulnerable populations affected by variants BA.1, BA.2, BA.5, and BQ.1 and including two national booster campaigns. Our database includes detailed information such as dates of diagnosis, hospitalization and death, last vaccination, and cause of death, among others. We evaluated the impact of vaccination on disease severity by age, variant, and vaccination status, finding that recent vaccination significantly mitigated severity across all Omicron subvariants, although efficacy waned six months post-vaccination, except for BQ.1, which showed more stable levels. Unvaccinated individuals had higher hospitalization and mortality rates. Our results highlight the importance of periodic vaccination to reduce severe outcomes, which are influenced by variant and vaccination timing. Although the seasonality of COVID-19 is uncertain, our analysis suggests the potential benefit of annual vaccination in populations >60 years old, probably in early fall, if COVID-19 eventually exhibits a major peak similar to other respiratory viruses.

Mortality in Catalonia during the summer of 2022 and its relation with high temperatures and COVID-19 cases.

Purpose: To analyse the association between the mortality during the summer 2022 and either high temperatures or the COVID-19 wave with data from the Catalan Health Care System (7.8 million people). Methods: We performed a retrospective study using publicly available data of meteorological variables, influenza-like illness (ILI) cases (including COVID-19) and deaths. The study comprises the summer months of the years 2021 and 2022. To compare the curves of mortality, ILI and temperature we calculated the z-score of each series. We assessed the observed lag between curves using the cross-correlation function. Finally, we calculated the correlation between the z-scores using the Pearson correlation coefficient (R2). Results: During the study period, 33,967 deaths were reported in Catalonia (16,416 in the summer of 2021 and 17,551 in the summer of 2022). In 2022, the observed lag and the correlation between the z-scores of temperature and all-cause deaths was 3 days and R2 = 0.86, while between ILI and all-cause deaths was 22 days and R2 = 0.21. This high correlation between temperature and deaths increased up to 0.91 when we excluded those deaths reported as COVID-19 deaths, while the correlation between ILI and non-COVID-19 deaths decreased to -0.19. No correlation was observed between non-COVID deaths and temperature or ILI cases in 2021. Conclusion: Our study suggests that the main cause of the increase in deaths during summer 2022 in Catalonia was the high temperatures and its duration. The contribution of the COVID-19 seems to be limited.

"Decline and uneven recovery from 7 common long-term conditions managed in the Catalan primary care after two pandemic years: an observational retrospective population-based study using primary care electronic health records".

BACKGROUND: The incidence of chronic diseases during the COVID-19 pandemic has drastically been reduced worldwide due to disruptions in healthcare systems. The aim of our study is to analyse the trends in the incidence of 7 commonly managed primary care chronic diseases during the last 2 years of the COVID-19 pandemic in Catalonia. METHODS: We performed an observational retrospective population-based study using data from primary care electronic health records from January 2018 to August 2022 (5.1 million people older than 14 years). We divided the study period into two: a pre-pandemic period (before 14 March 2020) and a pandemic period. We performed a segmented regression analysis of daily incidence rates per 100,000 inhabitants of 7 chronic diseases: type 2 diabetes mellitus (T2DM), asthma, chronic obstructive pulmonary disease (COPD), ischemic heart disease (IHD), heart failure (HF), hypertension and hypercholesterolemia. In addition, we compared annual incidence between pandemic years (2020, 2021 and 2022) and 2019. Associated incidence rate ratios (IRR) were also calculated. Finally, we estimated the number of expected diagnoses during the pandemic period using data from 2019 and we compared it with the observed data. RESULTS: We analysed 740,820 new chronic diseases' diagnoses. Daily incidence rates of all 7 chronic diseases were drastically interrupted on 14 March 2020, and a general upward trend was observed during the following months. Reductions in 2020 were around 30% for all conditions except COPD which had greater reductions (IRR: 0.58 [95% CI: 0.57 to 0.6]) and HF with lesser drops (IRR: 0.86 [95% CI: 0.84 to 0.88]). Some of the chronic conditions have returned to pre-pandemic diagnosis levels, except asthma, COPD and IHD. The return to pre-pandemic diagnosis levels compensated for the drops in 2020 for T2DM and HF, but not for hypertension which presented an incomplete recovery. We also observed an excess of hypercholesterolemia diagnoses of 8.5% (95%CI: 1.81% to 16.15%). CONCLUSIONS: Although primary care has recovered the pre-pandemic diagnosis levels for some chronic diseases, there are still missing diagnoses of asthma, COPD and IHD that should be addressed.

[SARS-CoV-2 infection in occupational settings in Catalonia.] / Infección por SARS-CoV-2 en las distintas ocupaciones en Cataluña.

OBJECTIVE: The aim of this paper was to estimate the SARS-CoV-2 infection incidence regarding the occupation in Catalonia, globally and in the different waves of the pandemic. METHODS: We performed a retrospective cohort study. We included all people between 16 and 65 years old with an occupation identified from the sick leave recorded in the primary care electronic health records of the Institut Català de la Salut (ICS) (total n=2,199,745 people). The study period was from March 1st, 2020 to September 16th, 2021. RESULTS: Healthcare workers had the highest incidence, with an age and sex adjusted cumulative rate of 27.7% [95% CI: 27.3%-28.1%]: 29.4% in nursing assistants, 27.3% in medical professions and 26.3% in nursing professionals; followed by the elementary occupations group with an adjusted incidence of 16.9% [95% CI: 16.7%-17%], such as the agricultural laborers (23% [95% CI: 21%-25.1%]) and rural occupations (19.1% [95% CI: 18.3%-19.8%) -especially during the 2020 summer period-, the domestic employees (20.5% [95% CI: 18.9%-22.2%]) and cleaning professionals (17.5% [95% CI: 17.2%-17.9%]). CONCLUSIONS: Healthcare workers are the hardest hit during the pandemic. On the other hand, the less qualified professions have high incidences, highlighting the different inequities in access to telework, working conditions and other social determinants of health.

OBJETIVO: El objetivo de este estudio fue estimar la incidencia de la infección por SARS-CoV-2 según la ocupación en Cataluña, tanto de forma global como en distintos periodos de la pandemia de COVID-19. METODOS: Se realizó un estudio retrospectivo de una cohorte. Se incluyeron todas las personas entre 16 y 65 años con una ocupación identificada a partir de las bajas laborales registradas en la historia clínica informatizada de Atención Primaria del Institut Català de la Salut (ICS) (N total=2.199.745 personas). El periodo de estudio fue del 1 de marzo de 2020 al 16 de septiembre de 2021. RESULTADOS: Las ocupaciones sanitarias fueron las que más incidencia tuvieron, con una tasa acumulada ajustada por edad y sexo del 27,7% [IC 95%: 27,3%-28,1%]: un 29,4% en auxiliares de enfermería, un 27,3% en profesionales de medicina y un 26,3% en profesionales de enfermería. Éstas fueron seguidas por el grupo de ocupaciones elementales con una incidencia ajustada de un 16,9% [IC 95%: 16,7 -17%], destacando en este grupo los peones agropecuarios (23% [IC 95%: 21%-25,1%]) y agrícolas (19,1% [IC 95%: 18,3%-19,8%]) ­especialmente en el periodo del verano de 2020­, los empleados domésticos (20,5% [IC 95%: 18,9%-22,2%) y los profesionales de limpieza (17,5% [IC 95%: 17,2%-17,9%]). CONCLUSIONES: Las ocupaciones sanitarias son las más afectadas durante la pandemia. Por otro lado, las ocupaciones menos cualificadas presentan también incidencias elevadas, poniendo de manifiesto las distintas inequidades en el acceso al teletrabajo, en las condiciones laborales y en otros determinantes sociales de la salud.

Respiratory Syncytial Virus Infections in Young Children Presenting to Primary Care in Catalonia During the COVID-19 Pandemic.

We observed an unusual pattern of respiratory syncytial virus (RSV) in children under 5 years in Catalonia (Spain). We observed a near absence of RSV during winter months and a subsequent surge during the late spring. Primary care electronic health records combined with hospital RSV laboratory confirmation could be used to monitor trends of respiratory pathogens.

Comparative effectiveness and safety of homologous two-dose ChAdOx1 versus heterologous vaccination with ChAdOx1 and BNT162b2.

Small trials have suggested that heterologous vaccination with first-dose ChAdOx1 and second-dose BNT162b2 may generate a better immune response than homologous vaccination with two doses of ChAdOx1. In this cohort analysis, we use linked data from Catalonia (Spain), where those aged <60 who received a first dose of ChAdOx1 could choose between ChAdOx1 and BNT162b2 for their second dose. Comparable cohorts were obtained after exact-matching 14,325/17,849 (80.3%) people receiving heterologous vaccination to 14,325/149,386 (9.6%) receiving homologous vaccination by age, sex, region, and date of second dose. Of these, 464 (3.2%) in the heterologous and 694 (4.8%) in the homologous groups developed COVID-19 between 1st June 2021 and 5th December 2021. The resulting hazard ratio (95% confidence interval) is 0.66 [0.59-0.74], favouring heterologous vaccination. The two groups had similar testing rates and safety outcomes. Sensitivity and negative control outcome analyses confirm these findings. In conclusion, we demonstrate that a heterologous vaccination schedule with ChAdOx1 followed by BNT162b2 was more efficacious than and similarly safe to homologous vaccination with two doses of ChAdOx1. Most of the infections in our study occurred when Delta was the predominant SARS-CoV-2 variant in Spain. These data agree with previous phase 2 randomised trials.

Transmissibility, hospitalization, and intensive care admissions due to omicron compared to delta variants of SARS-CoV-2 in Catalonia: A cohort study and ecological analysis.

Purpose: We aim to compare the severity of infections between omicron and delta variants in 609,352 SARS-CoV-2 positive cases using local hospitalization, vaccination, and variants data from the Catalan Health Care System (which covers around 7. 8 million people). Methods: We performed a substitution model to establish the increase in transmissibility of omicron using variant screening data from primary care practices (PCP) and hospital admissions. In addition, we used this data from PCP to establish the two periods when delta and omicron were, respectively, dominant (above 95% of cases). After that, we performed a population-based cohort analysis to calculate the rates of hospital and intensive care unit (ICU) admissions for both periods and to estimate reduction in severity. Rate ratios (RR) and 95% confidence intervals (95% CI) were calculated and stratified by age and vaccination status. In a second analysis, the differential substitution model in primary care vs. hospitals allowed us to obtain a population-level average change in severity. Results: We have included 48,874 cases during the delta period and 560,658 during the omicron period. During the delta period, on average, 3.8% of the detected cases required hospitalization for COVID-19. This percentage dropped to 0.9% with omicron [RR of 0.46 (95% CI: 0.43 to 0.49)]. For ICU admissions, it dropped from 0.8 to 0.1% [RR 0.25 (95% CI: 0.21 to 0.28)]. The proportion of cases hospitalized or admitted to ICU was lower in the vaccinated groups, independently of the variant. Omicron was associated with a reduction in risk of admission to hospital and ICU in all age and vaccination status strata. The differential substitution models showed an average RR between 0.19 and 0.50. Conclusion: Both independent methods consistently show an important decrease in severity for omicron relative to delta. The systematic reduction happens regardless of age. The severity is also reduced for non-vaccinated and vaccinated groups, but it remains always higher in the non-vaccinated population. This suggests an overall reduction in severity, which could be intrinsic to the omicron variant. The fact is that the RR in ICU admission is systematically smaller than in hospitalization points in the same direction.

Corrigendum: Transmissibility, hospitalization, and intensive care admissions due to omicron compared to delta variants of SARS-CoV-2 in Catalonia: A cohort study and ecological analysis.

[This corrects the article DOI: 10.3389/fpubh.2022.961030.].

Individual prevention and containment measures in schools in Catalonia, Spain, and community transmission of SARS-CoV-2 after school re-opening.

BACKGROUND: Despite their clear lesser vulnerability to COVID-19, the extent by which children are susceptible to getting infected by SARS-CoV-2 and their capacity to transmit the infection to other people remains inadequately characterized. We aimed to evaluate the role of school reopening and the preventive strategies in place at schools in terms of overall risk for children and community transmission, by comparing transmission rates in children as detected by a COVID-19 surveillance platform in place in Catalonian Schools to the incidence at the community level. METHODS AND FINDINGS: Infections detected in Catalan schools during the entire first trimester of classes (September-December 2020) were analysed and compared with the ongoing community transmission and with the modelled predicted number of infections. There were 30.486 infections (2.12%) documented among the circa 1.5M pupils, with cases detected in 54.0% and 97.5% of the primary and secondary centres, respectively. During the entire first term, the proportion of "bubble groups" (stable groups of children doing activities together) that were forced to undergo confinement ranged between 1 and 5%, with scarce evidence of substantial intraschool transmission in the form of chains of infections, and with ~75% of all detected infections not leading to secondary cases. Mathematical models were also used to evaluate the effect of different parameters related to the defined preventive strategies (size of the bubble group, number of days of confinement required by contacts of an index case). The effective reproduction number inside the bubble groups in schools (R*), defined as the average number of schoolmates infected by each primary case within the bubble, was calculated, yielding a value of 0.35 for primary schools and 0.55 for secondary schools, and compared with the outcomes of the mathematical model, implying decreased transmissibility for children in the context of the applied measures. Relative homogenized monthly cumulative incidence ([Formula: see text]) was assessed to compare the epidemiological dynamics among different age groups and this analysis suggested the limited impact of infections in school-aged children in the context of the overall community incidence. CONCLUSIONS: During the fall of 2020, SARS-CoV-2 infections and COVID-19 cases detected in Catalan schools closely mirrored the underlying community transmission from the neighbourhoods where they were set and maintaining schools open appeared to be safe irrespective of underlying community transmission. Preventive measures in place in those schools appeared to be working for the early detection and rapid containment of transmission and should be maintained for the adequate and safe functioning of normal academic and face-to-face school activities.

Construction and validation of a scoring system for the selection of high-quality data in a Spanish population primary care database (SIDIAP).

BACKGROUND: Computerised databases of primary care clinical records are widely used for epidemiological research. In Catalonia, the Information System for the Development of Research in Primary Care (SIDIAP) aims to promote the development of research based on high-quality validated data from primary care electronic medical records. OBJECTIVE: The purpose of this study is to create and validate a scoring system (Registry Quality Score, RQS) that will enable all primary care practices (PCPs) to be selected as providers of researchusable data based on the completeness of their registers. METHODS: Diseases that were likely to be representative of common diagnoses seen in primary care were selected for RQS calculations. The observed/expected cases ratio was calculated for each disease. Once we had obtained an estimated value for this ratio for each of the selected conditions we added up the ratios calculated for each condition to obtain a final RQS. Rate comparisons between observed and published prevalences of diseases not included in the RQS calculations (atrial fibrillation, diabetes, obesity, schizophrenia, stroke, urinary incontinence and Crohn's disease) were used to set the RQS cutoff which will enable researchers to select PCPs with research-usable data. RESULTS: Apart from Crohn's disease, all prevalences were the same as those published from the RQS fourth quintile (60th percentile) onwards. This RQS cut-off provided a total population of 1 936 443 (39.6% of the total SIDIAP population). CONCLUSIONS: SIDIAP is highly representative of the population of Catalonia in terms of geographical, age and sex distributions. We report the usefulness of rate comparison as a valid method to establish research-usable data within primary care electronic medical records.

Impact of the COVID-19 pandemic and related control measures on cancer diagnosis in Catalonia: a time-series analysis of primary care electronic health records covering about five million people.

OBJECTIVE: Cancer care has been disrupted by the response of health systems to the COVID-19 pandemic, especially during lockdowns. The objective of our study is to evaluate the impact of the pandemic on the incidence of cancer diagnoses in primary care. DESIGN: Time-series study of malignant neoplasms and diagnostic procedures, using data from the primary care electronic health records from January 2014 to September 2020. SETTING: Primary care, Catalonia, Spain. PARTICIPANTS: People older than 14 years and assigned in one of the primary care practices of the Catalan Institute of Health with a new diagnosis of malignant neoplasm. MAIN OUTCOME MEASURES: We obtained the monthly expected incidence of malignant neoplasms using a temporary regression, where the response variable was the incidence of cancer from 2014 to 2018 and the adjustment variables were the trend and seasonality of the time series. Excess or lack of malignant neoplasms was defined as the number of observed minus expected cases, globally and stratified by sex, age, type of cancer and socioeconomic status. RESULTS: Between March and September 2020 we observed 8766 (95% CI 4135 to 13 397) fewer malignant neoplasm diagnoses, representing a reduction of 34% (95% CI 19.5% to 44.1%) compared with the expected. This underdiagnosis was greater in individuals aged older than 64 years, men and in some types of cancers (skin, colorectal, prostate). Although the reduction was predominantly focused during the lockdown, expected figures have not yet been reached (40.5% reduction during the lockdown and 24.3% reduction after that). CONCLUSIONS: Reduction in cancer incidence has been observed during and after the lockdown. Urgent policy interventions are necessary to mitigate the indirect effects of the COVID-19 pandemic and related control measures on other diseases and some strategies must be designed in order to reduce the underdiagnosis of cancer.