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.

Investigating epidemiological distribution (temporality and intensity) of respiratory pathogens following COVID-19 de-escalation process in Catalonia, September 2016-June 2021: Analysis of regional surveillance data.

BACKGROUND: Following the low incidence rates of non-SARS-CoV-2 respiratory viruses registered during the strict lockdown enforced in the pandemic, a resurgence of several endemic viruses in Catalonia (Spain) was noted during the early summer of 2021. OBJECTIVES: In this study, we investigated whether the circulation of non-SARS-CoV-2 respiratory viruses in Catalonia, assessed by Microbiological Reporting System of Catalonia (MRSC) and the Epidemiological Surveillance Network of Catalonia, was affected by the strict lockdown measures, as well as, the implication of the Coronavirus Disease 19 (COVID-19) de-escalation process in the late season outbreaks registered during the 2020-2021 season. STUDY DESIGN: A retrospective comparison of epidemic patterns in the respiratory viruses' incidence, using regional public health surveillance data from MRSC, was performed between weeks 26/2016 to week 27/2021. Data were expressed as the weekly total number of test positivity for individual viruses. A segmented negative binomial regression model was conducted, with two parameters included (level and trend) for each segment of the time series (2020 pre-lockdown, 2020 post-lockdown and 2021). Results were reported as a unit changed in the strict lockdown. RESULTS: A total of 51588 confirmed cases of the different respiratory viruses were included in the analysis, the majority were influenza cases (63.7%). An immediate reduction in the weekly number of cases was observed in 2020 after the COVID-19 outbreak for human adenovirus virus (HAdV) (ß2 = -2.606; P <0.01), human parainfluenza virus (HPIV) (ß2 = -3.023; P <0.01), influenza virus (IFV) (ß2 = -1.259; P <0.01), but not for respiratory syncytial virus (RSV), where the number of cases remained unchanged. During 2020, a significant negative trend was found for RSV (ß3 = -0.170, P <0.01), and a positive trend for HAdV (ß3 = 0.075, P <0.01). During 2021, a significant reduction in the weekly number of cases was also observed for all respiratory viruses, and a borderline non-significant reduction for HPIV (ß3 = -0.027; P = 0.086). Moreover, significant positive trends were found for each viral pathogen, except for influenza during 2020-2021 season, where cases remained close to zero. The respiratory viruses increased activity and their late season epidemic start particularly affected children under 6 years old. CONCLUSIONS: Our data not only provides evidence that occurrence of different respiratory virus infections was affected by the strict lockdown taken against SARS-CoV-2 but it also shows a late resurgence of seasonal respiratory viruses' cases during the 2020-2021 season following the relaxation of COVID-19-targeted non-pharmaceutical interventions.

Costs and Factors Associated with Hospitalizations Due to Severe Influenza in Catalonia (2017-2020).

This study aimed to estimate the cost and factors associated with severe hospitalized patients due to influenza in unvaccinated and vaccinated cases. The study had a cross-sectional design and included three influenza seasons in 16 sentinel hospitals in Catalonia, Spain. Data were collected from a surveillance system of influenza and other acute respiratory infections. Generalized linear models (GLM) were used to analyze mean costs stratified by comorbidities and pregnancy. Multivariate logistic models were used to analyze bacterial coinfection, multi-organ failure, acute respiratory distress syndrome, death and ICU admission by season and by vaccination status. Costs of ICU, hospitalization and total mean costs were analyzed using GLM, by season and by vaccination status. All models were adjusted for age and sex. A total of 2742 hospitalized cases were included in the analyses. Cases were mostly aged ≥ 60 years (70.17%), with recommended vaccination (86.14%) and unvaccinated (68.05%). The ICU admission level was statistically significant higher in unvaccinated compared to vaccinated cases. Costs of cases with more than or equal to two comorbidities (Diff = EUR - 1881.32), diabetes (Diff = EUR - 1953.21), chronic kidney disease (Diff = EUR - 2260.88), chronic cardiovascular disease (Diff = EUR - 1964.86), chronic liver disease (Diff = EUR - 3595.60), hospitalization (EUR 9419.42 vs. EUR 9055.45), and total mean costs (EUR 11,540.04 vs. 10,221.34) were statistically significant higher in unvaccinated compared to vaccinated patients. The influenza vaccine reduces the costs of hospitalization. There is a need to focus strategies in recommended vaccination groups.

COVID-19 vaccine effectiveness against hospitalization due to SARS-CoV-2: A test-negative design study based on Severe Acute Respiratory Infection (SARI) sentinel surveillance in Spain.

BACKGROUND: With the emergence of SARS-CoV-2, influenza surveillance systems in Spain were transformed into a new syndromic sentinel surveillance system. The Acute Respiratory Infection Surveillance System (SiVIRA in Spanish) is based on a sentinel network for acute respiratory infection (ARI) surveillance in primary care and a network of sentinel hospitals for severe ARI (SARI) surveillance in hospitals. METHODS: Using a test-negative design and data from SARI admissions notified to SiVIRA between January 1 and October 3, 2021, we estimated COVID-19 vaccine effectiveness (VE) against hospitalization, by age group, vaccine type, time since vaccination, and SARS-CoV-2 variant. RESULTS: VE was 89% (95% CI: 83-93) against COVID-19 hospitalization overall in persons aged 20 years and older. VE was higher for mRNA vaccines, and lower for those aged 80 years and older, with a decrease in protection beyond 3 months of completing vaccination, and a further decrease after 5 months. We found no differences between periods with circulation of Alpha or Delta SARS-CoV-2 variants, although variant-specific VE was slightly higher against Alpha. CONCLUSIONS: The SiVIRA sentinel hospital surveillance network in Spain was able to describe clinical and epidemiological characteristics of SARI hospitalizations and provide estimates of COVID-19 VE in the population under surveillance. Our estimates add to evidence of high effectiveness of mRNA vaccines against severe COVID-19 and waning of protection with time since vaccination in those aged 80 or older. No substantial differences were observed between SARS-CoV-2 variants (Alpha vs. Delta).

Effectiveness of complete primary vaccination against COVID-19 at primary care and community level during predominant Delta circulation in Europe: multicentre analysis, I-MOVE-COVID-19 and ECDC networks, July to August 2021.

IntroductionIn July and August 2021, the SARS-CoV-2 Delta variant dominated in Europe.AimUsing a multicentre test-negative study, we measured COVID-19 vaccine effectiveness (VE) against symptomatic infection.MethodsIndividuals with COVID-19 or acute respiratory symptoms at primary care/community level in 10 European countries were tested for SARS-CoV-2. We measured complete primary course overall VE by vaccine brand and by time since vaccination.ResultsOverall VE was 74% (95% CI: 69-79), 76% (95% CI: 71-80), 63% (95% CI: 48-75) and 63% (95% CI: 16-83) among those aged 30-44, 45-59, 60-74 and ≥ 75 years, respectively. VE among those aged 30-59 years was 78% (95% CI: 75-81), 66% (95% CI: 58-73), 91% (95% CI: 87-94) and 52% (95% CI: 40-61), for Comirnaty, Vaxzevria, Spikevax and COVID-19 Vaccine Janssen, respectively. VE among people 60 years and older was 67% (95% CI: 52-77), 65% (95% CI: 48-76) and 83% (95% CI: 64-92) for Comirnaty, Vaxzevria and Spikevax, respectively. Comirnaty VE among those aged 30-59 years was 87% (95% CI: 83-89) at 14-29 days and 65% (95% CI: 56-71%) at ≥ 90 days between vaccination and onset of symptoms.ConclusionsVE against symptomatic infection with the SARS-CoV-2 Delta variant varied among brands, ranging from 52% to 91%. While some waning of the vaccine effect may be present (sample size limited this analysis to only Comirnaty), protection was 65% at 90 days or more between vaccination and onset.

Surveillance of influenza B severe hospitalized cases during 10 seasons in Catalonia: Does the lineage make a difference?

Influenza B viruses circulate in two lineages (B/Victoria and B/Yamagata). Although classically affecting children, recently it has shown a high rate of infection and increased hospitalization in the elderly. To describe and analyze the clinical and epidemiological characteristics of severe hospitalized laboratory-confirmed influenza B virus (SHLCI-B) cases in Catalonia associated with mismatch from Influenza B virus strain included in the trivalent influenza vaccine (TIV). SHLCI-B was registered by the influenza sentinel surveillance system of Catalonia (PIDIRAC) during ten surveillance seasons from 2010 to 2020. Variables age, comorbidities, and vaccination status were recorded. Vaccine effectiveness was estimated as (1-OR) for intensive care unit (ICU) admission. Statistical significance was established at p < 0.05. A total of 1159 SHLCI-B were registered, of these 68.2% (791) corresponded to the 2017-2018 season; 21.8% (253) were admitted to ICU and 13.8% (160) were exitus; 62.5% (725) cases occurred in those aged >64 years; most frequent risk factor was cardiovascular disease (35.1%, 407) followed by chronic pulmonary obstructive disease-COPD (24.6%, 285) and diabetes (24.1%, 279). In four seasons, the predominant circulating lineage was B/Victoria, in two seasons the B/Yamagata lineage and four seasons had no IBV activity. Four seasons presented discordance with the strain included within the TIV. Vaccine effectiveness (VE) to prevent ICU admission was 31% (95% confidence interval [CI]: 4%-51%; p = 0.03); being 29% (95% CI: -3% to 51%) in discordant and 43% (95% CI:-43% to 77%) in concordant seasons. Significant differences were observed in the number of affected aged > 64 years (odds ratio [OR] = 2.5; 95% CI: 1.9-3.4; p < 0.001) and in patients with heart disease (OR = 2.40 95% CI: 1.7-3.4; p < 0.001), COPD (OR = 1.6 95% CI: 1.1-2.3; p = 0.01), and diabetes (OR = 1.5 95% CI: 1.1-2.1; p = 0.04) between discordant and concordant seasons. The increase in hospitalization rate in people> 64 years of age and those presenting comorbidities in seasons with circulating influenza B virus belonging to a lineage discordant with the strain included in the TIV and the decrease of VE to prevent ICU admissions evidence the vital need to administer the quadrivalent influenza vaccine regardless of the findings of predominant circulation in the previous season.

Surveillance of SARS-CoV-2 virus circulation using Acute Respiratory Infections sentinel system of Catalonia (PIDIRAC) during the 2019-2020 season: A retrospective observational study.

BACKGROUND: In the context of COVID-19 pandemic in Catalonia (Spain), the present study analyses respiratory samples collected by the primary care network using Acute Respiratory Infections Sentinel Surveillance System (PIDIRAC) during the 2019-2020 season to complement the pandemic surveillance system in place to detect SARS-CoV-2. The aim of the study is to describe whether SARS-CoV-2 was circulating before the first confirmed case was detected in Catalonia, on February 25th, 2020. METHODS: The study sample was made up of all samples collected by the PIDIRAC primary care network as part of the Influenza and Acute Respiratory Infections (ARI) surveillance system activities. The study on respiratory virus included coronavirus using multiple RT-PCR assays. All positive samples for human coronavirus were subsequently typed for HKU1, OC43, NL63, 229E. Every respiratory sample was frozen at-80°C and retrospectively studied for SARS-CoV-2 detection. A descriptive study was performed, analysing significant differences among variables related to SARS-CoV- 2 cases comparing with rest of coronaviruses cases through a bivariate study with Chi-squared test and statistical significance at 95%. RESULTS: Between October 2019 and April 2020, 878 respiratory samples from patients with acute respiratory infection or influenza syndrome obtained by PIDIRAC were analysed. 51.9% tested positive for influenza virus, 48.1% for other respiratory viruses. SARS-CoV-2 was present in 6 samples. The first positive SARS-CoV-2 case had symptom onset on 2 March 2020. These 6 cases were 3 men and 3 women, aged between 25 and 50 years old. 67% had risk factors, none had previous travel history nor presented viral coinfection. All of them recovered favourably. CONCLUSION: Sentinel Surveillance PIDIRAC enhances global epidemiological surveillance by allowing confirmation of viral circulation and describes the epidemiology of generalized community respiratory viruses' transmission in Catalonia. The system can provide an alert signal when identification of a virus is not achieved in order to take adequate preparedness measures.

SARS-CoV-2 seroprevalence in blood donors before and after the first wave in Catalonia (Spain).

BACKGROUND: Due to the COVID-19 pandemic, a national lockdown was applied in Spain from March to May 2020. It is uncertain when SARS-CoV-2 started to circulate in Catalonia, and only a few cases were diagnosed in this period. We assessed the SARS-CoV-2 seroprevalence in blood donors before and after the first wave and compared it with public health service (PHS) data. MATERIALS AND METHODS: Retrospective archive or prospective fresh blood samples were obtained from blood donors aged 18 to 70 and anonymized after demographic data had been recorded (gender, age, place of residence, blood collection date). Two CE-marked enzyme-linked immunosorbent assays were used to test for anti-SARS-CoV-2. A SARS-CoV-2 IgM test was additionally performed in positive samples. Individuals aged 18 to 70 from among the general population diagnosed as having SARS-CoV-2 by the PHS were included for comparison with blood donor results. RESULTS: A total of 10,170 blood donations were included in the first period, between 24 February and 9 March 2020, and 6,829 in the second period, between 16 May and 17 June 2020. The observed SARS-CoV-2 seroprevalence among blood donors rose from 0.27% (95% CI: 0.18-0.39) before the first wave to 5.55% (95% CI: 5.03-6.12) after it, and was even higher (6.90% [95% CI: 5.64-8.41]) among blood donors aged 18 to 29. The seroprevalence among blood donors was higher in more populated areas (Barcelona: 7.69%). A comparison of blood donor data with officially diagnosed cases showed a global 87.44% underestimation of SARS-CoV-2 in June 2020. DISCUSSION: We analyzed the explosive 3-month increase in blood donor SARS-CoV-2 seroprevalence (from 0.27% to 5.55%) and show that more than 87% of cases went undiagnosed, despite the unprecedented deployment of testing measures. SARS-CoV-2 IgM results suggest that the virus was circulating among blood donors in February 2020. Blood donors are definitively proven to be a valuable resource for emerging disease surveillance studies.

Lack of Prognostic Value of SARS-CoV2 RT-PCR Cycle Threshold in the Community.

The immense impact of the COVID-19 pandemic on health systems has motivated the scientific community to search for clinical prognostic factors for SARS-CoV-2 infection. Low cycle threshold values (Ct) of diagnostic real-time RT-PCR assays in hospitalized patients have been associated with a poor prognosis in several studies, whereas other studies did not find this association. We explored whether SARS-CoV-2 Ct values at diagnosis were associated with a poor outcome (admission to hospital and death) in 604 community patients diagnosed at primary health centers. Although lower Ct values were found in patients who died of COVID-19, the Ct value was not significantly associated with a worse outcome in a multivariate analysis, while age remained an independent prognostic factor. We did not find evidence to support the role of Ct values as a prognostic factor of COVID-19 in community cases.

Diagnostic Performance of Ag-RDTs and NAAT for SARS-CoV2 Identification in Symptomatic Patients in Catalonia.

The use of rapid antigenic tests (Ag-RDTs) to diagnose a SARS-CoV-2 infection has become a common practice recently. This study aimed to evaluate performance of Abbott PanbioTM Ag-RDTs with regard to nucleic acid amplification testing (NAAT) in the early stages of the disease. A cohort of 149,026 infected symptomatic patients, reported in Catalonia from November 2020 to January 2021, was selected. The positivity rates of the two tests were compared with respect to the dates of symptom onset. Ag-RDTs presented positivity rates of 84% in the transmission phases of the disease and 31% in the pre-symptomatic period, compared to 93% and 91%, respectively, for NAAT. The detection of many false negatives with Ag-RDTs during the pre-symptomatic period demonstrates the risk of virus dissemination with this diagnostic technique if used outside the symptomatic period.

Impact of an oral anticoagulation self-monitoring and self-management program in patients with mechanical heart valve prosthesis.

Objective: To analyze impact of implementation of an oral anticoagulation self-monitoring and self-management program among patients with mechanical valve prosthesis. Materials & methods: Observational and retrospective study performed in Hospital Moises Broggi, Barcelona, Spain. The program started on June 2019. The study compared 6-month period before and after the implementation of the program. Results: The study included 44 patients. There was a numerical increase of time in therapeutic range from 53.6 ± 21.3% to 57.1 ± 15.7% (p = 0.30). Proportion of patients with international normalized ratio (INR) >5 significantly decreased from 3.9 to 2.0% (p = 0.04). No significant differences were observed in thromboembolic or bleeding complications. Visits to emergency department decreased from (29.5 to 22.7%; p = 0.41). Conclusion: Oral anticoagulation self-monitoring and self-management program seems an appropriate approach that could provide additional benefits in selected patients with mechanical valve prosthesis.

Impact of prescription patterns of antithrombotic treatment on atrial fibrillation-related ischemic stroke.

OBJECTIVE: To analyze the temporal trends of atrial fibrillation (AF)-related ischemic stroke (IS) and their relationship with the prescription patterns of antithrombotic treatment from 2013 to 2019 in the Health Assistance Area of a regional hospital. METHODS: First, a retrospective ecological study of aggregate data to analyze the annual incidence of IS between 2013 and 2019 was performed. Second, we selected those patients diagnosed with AF between 2013 and 2019 and performed a retrospective longitudinal study to assess the role of antithrombotic therapy in the development of AF-related IS. RESULTS: During this period, whereas the annual incidence of IS remained stable (from 1.3 in 2013 to 1.2 cases per 1000 inhabitants in 2019; adjusted P for trend .829), the annual incidence of AF-related IS decreased over time (from 23.8 to 18.8 cases per 1000 inhabitants, respectively; adjusted P for trend .001). Among AF patients, the use of direct oral anticoagulants increased from 5.5% to 46.8%, while the prescription of antiplatelets and vitamin K antagonists decreased from 21.9% to 6.0% and from 63.8% to 36.1%, respectively. Overall, the use of oral anticoagulants increased from 69.3% to 82.9%; p < .001. Patients under antiplatelet agents had a higher probability of presenting IS than those patients taking oral anticoagulants, either vitamin K antagonists or direct oral anticoagulants (adjusted OR 1.89; 95% CI 1.52-2.37; p < .001). CONCLUSIONS: The prescription of oral anticoagulants, particularly direct oral anticoagulants, has increased from 2013 to 2019 in our Health Assistance Area. This increase might partially explain the reduction in AF-related IS.

Mejorar la atención médica mediante un modelo integrado de asistencia para pacientes con cardiopatía isquémica o fibrilación auricular / Improving medical attention through an integral care model for patients with ischemic heart disease or atrial fibrillation

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Assessment of two complementary influenza surveillance systems: sentinel primary care influenza-like illness versus severe hospitalized laboratory-confirmed influenza using the moving epidemic method.

BACKGROUND: Monitoring seasonal influenza epidemics is the corner stone to epidemiological surveillance of acute respiratory virus infections worldwide. This work aims to compare two sentinel surveillance systems within the Daily Acute Respiratory Infection Information System of Catalonia (PIDIRAC), the primary care ILI and Influenza confirmed samples from primary care (PIDIRAC-ILI and PIDIRAC-FLU) and the severe hospitalized laboratory confirmed influenza system (SHLCI), in regard to how they behave in the forecasting of epidemic onset and severity allowing for healthcare preparedness. METHODS: Epidemiological study carried out during seven influenza seasons (2010-2017) in Catalonia, with data from influenza sentinel surveillance of primary care physicians reporting ILI along with laboratory confirmation of influenza from systematic sampling of ILI cases and 12 hospitals that provided data on severe hospitalized cases with laboratory-confirmed influenza (SHLCI-FLU). Epidemic thresholds for ILI and SHLCI-FLU (overall) as well as influenza A (SHLCI-FLUA) and influenza B (SHLCI-FLUB) incidence rates were assessed by the Moving Epidemics Method. RESULTS: Epidemic thresholds for primary care sentinel surveillance influenza-like illness (PIDIRAC-ILI) incidence rates ranged from 83.65 to 503.92 per 100.000 h. Paired incidence rate curves for SHLCI -FLU / PIDIRAC-ILI and SHLCI-FLUA/ PIDIRAC-FLUA showed best correlation index' (0.805 and 0.724 respectively). Assessing delay in reaching epidemic level, PIDIRAC-ILI source forecasts an average of 1.6 weeks before the rest of sources paired. Differences are higher when SHLCI cases are paired to PIDIRAC-ILI and PIDIRAC-FLUB although statistical significance was observed only for SHLCI-FLU/PIDIRAC-ILI (p-value Wilcoxon test = 0.039). CONCLUSIONS: The combined ILI and confirmed influenza from primary care along with the severe hospitalized laboratory confirmed influenza data from PIDIRAC sentinel surveillance system provides timely and accurate syndromic and virological surveillance of influenza from the community level to hospitalization of severe cases.

Epidemiology of congenital Chagas disease 6 years after implementation of a public health surveillance system, Catalonia, 2010 to 2015.

BackgroundChagas disease is endemic in Latin America and affects 8 million people worldwide. In 2010, Catalonia introduced systematic public health surveillance to detect and treat congenital Chagas disease.AimThe objective was to evaluate the health outcomes of the congenital Chagas disease screening programme during the first 6 years (2010-2015) after its introduction in Catalonia.MethodsIn a surveillance system, we screened pregnant women and newborns and other children of positive mothers, and treated Chagas-positive newborns and children. Diagnosis was confirmed for pregnant women and children with two positive serological tests and for newborns with microhaematocrit and/or PCR at birth or serology at age 9 months.ResultsFrom 2010 to 2015, the estimated screening coverage rate increased from 68.4% to 88.6%. In this period, 33,469 pregnant women were tested for Trypanosoma cruzi and 937 positive cases were diagnosed. The overall prevalence was 2.8 cases per 100 pregnancies per year (15.8 in Bolivian women). We followed 82.8% of newborns until serological testing at age 9-12 months and 28 were diagnosed with Chagas disease (congenital transmission rate: 4.17%). Of 518 siblings, 178 (34.3%) were tested and 14 (7.8%) were positive for T. cruzi. Having other children with Chagas disease and the heart clinical form of Chagas disease were maternal risk factors associated with congenital T. cruzi infection (p < 0.05).ConclusionThe increased screening coverage rate indicates consolidation of the programme in Catalonia. The rate of Chagas disease congenital transmission in Catalonia is in accordance with the range in non-endemic countries.

Impact of an integral assistance model between primary care and cardiology on the management of patients with ischemic heart disease or atrial fibrillation.

AIM: To analyze the impact of implementing a program integrating cardiology and primary care in clinical practice. METHODS: In the integrated care model, every cardiologist was assigned to each primary care center. RESULTS & CONCLUSION: The implementation of the new care model was associated with a significant reduction of 31.2% in requests of first visits. In addition, the delay to the cardiologist consultation significantly decreased by 54.5% for the first visits, and by 57.1% for the follow-up visits. The proportion of patients that achieved recommended low density lipoprotein-cholesterol goals significantly increased from 20.8 to 29.6%. The proportion of patients submitted to anticoagulant therapy significantly increased from 69.3 to 74.2%, as well as the proportion of patients taking direct oral anticoagulants (from 7.9 to 28.4%).

Descriptive study of severe hospitalized cases of laboratory-confirmed influenza during five epidemic seasons (2010-2015).

OBJECTIVE: The Plan of Information on Acute Respiratory Infections in Catalonia (PIDIRAC) included the surveillance of severe hospitalized cases of laboratory-confirmed influenza (SHCLCI) in 2009. The objective of this study was to determine the clinical, epidemiological and virological features of SHCLCI recorded in 12 sentinel hospitals during five influenza seasons. RESULTS: From a sample of SHCLCI recorded during the 5 influenza epidemics seasons from 2010-2011 to 2014-2015, Cases were confirmed by PCR and/or viral isolation in cell cultures from respiratory samples. A total of 1400 SHCLCI were recorded, 33% required ICU admission and 12% died. The median age of cases was 61 years (range 0-101 years); 70.5% were unvaccinated; 80.4% received antiviral treatment (in 79.6 and 24% of cases within 48 h after hospital admission and the onset of symptoms, respectively); influenza virus A [37.9% A (H1N1)pdm09, 29.3% A (H3N2)] was identified in 87.7% of cases. Surveillance of SHCLCI provides an estimate of the severity of seasonal influenza epidemics and the identification and characterization of at-risk groups in order to facilitate preventive measures such as vaccination and early antiviral treatment.

Real-time predictive seasonal influenza model in Catalonia, Spain.

Influenza surveillance is critical to monitoring the situation during epidemic seasons and predictive mathematic models may aid the early detection of epidemic patterns. The objective of this study was to design a real-time spatial predictive model of ILI (Influenza Like Illness) incidence rate in Catalonia using one- and two-week forecasts. The available data sources used to select explanatory variables to include in the model were the statutory reporting disease system and the sentinel surveillance system in Catalonia for influenza incidence rates, the official climate service in Catalonia for meteorological data, laboratory data and Google Flu Trend. Time series for every explanatory variable with data from the last 4 seasons (from 2010-2011 to 2013-2014) was created. A pilot test was conducted during the 2014-2015 season to select the explanatory variables to be included in the model and the type of model to be applied. During the 2015-2016 season a real-time model was applied weekly, obtaining the intensity level and predicted incidence rates with 95% confidence levels one and two weeks away for each health region. At the end of the season, the confidence interval success rate (CISR) and intensity level success rate (ILSR) were analysed. For the 2015-2016 season a CISR of 85.3% at one week and 87.1% at two weeks and an ILSR of 82.9% and 82% were observed, respectively. The model described is a useful tool although it is hard to evaluate due to uncertainty. The accuracy of prediction at one and two weeks was above 80% globally, but was lower during the peak epidemic period. In order to improve the predictive power, new explanatory variables should be included.

Influenza vaccine effectiveness assessment through sentinel virological data in three post-pandemic seasons.

Influenza vaccination aims at reducing the incidence of serious disease, complications and death among those with the most risk of severe influenza disease. Influenza vaccine effectiveness (VE) through sentinel surveillance data from the PIDIRAC program (Daily Acute Respiratory Infection Surveillance of Catalonia) during 2010-2011, 2011-2012, and 2012-2013 influenza seasons, with three different predominant circulating influenza virus (IV) types [A(H1N1)pdm09, A(H3N2) and B, respectively] was assessed. The total number of sentinel samples with known vaccination background collected during the study period was 3173, 14.7% of which had received the corresponding seasonal influenza vaccine. 1117 samples (35.2%) were positive for IV. A retrospective negative case control design was used to assess vaccine effectiveness (VE) for the entire period and for each epidemic influenza season. An overall VE of 58.1% (95% CI:46.8-67) was obtained. Differences in VE according to epidemic season were observed, being highest for the 2012-2013 season with predominance of IV type B (69.7% ;95% CI:51.5-81) and for the 2010-2011 season, with predominance of the A(H1N1)pdm09 influenza virus strain (67.2% ;95%CI:49.5-78.8) and lowest for the 2011-2012 season with A(H3N2) subtype predominance (34.2% ;95%CI:4.5-54.6). Influenza vaccination prevents a substantial number of influenza-associated illnesses. Although vaccines with increased effectiveness are needed and the search for a universal vaccine that is not subject to genetic modifications might increase VE, nowadays only the efforts to increase vaccination rates of high-risk population and healthcare personnel let reduce the burden of influenza and its complications.