Observational Studies

Observational Studies

Observational studies focus on "observing and recording" events without intervening in their natural course.

In them, the researcher is a mere observer and descriptor of what happens. Data measurement can be done in different ways: over time (prospective and retrospective); they can be descriptive, when the intention is to "describe and record" what is observed, such as the behaviour of one or more variables in a group of subjects; or analytical, which are those that allow "comparing groups of subjects."



  • EPI RSV 022- Epidemiological study to assess the disease burden of acute respiratory infection (ARTI) associated with the respiratory syncytial virus (RSV) in adults over 50 years of age during two consecutive RSV seasons in the United States and Europe. Objective: Estudio epidemiológico para evaluar la carga de enfermedad de la infección respiratoria aguda (IRA) asociada al virus respiratorio sincitial (VRS) en adultos mayores de 50 años durante dos temporadas consecutivas de VRS en Estados Unidos y Europa.
  • Estimation of the loss of quality of life due to infection by the respiratory syncytial virus (RSV) in children under 2 years of age and their relatives in the Valencian Community and Catalonia. Objective: Objective: To analyze the loss of health-related quality of life (HRQL) due to RSV disease in children under 2 years of age and their families in the Valencian Community. (Multicenter study). See Study.
  • Needs for future pharmacoeconomic analysis of RSV vaccines: Assessing the burden of pediatric RSV disease and QALYs lost. (Phase I: prospective study). Objective: The main objective of the study is to estimate the quality-adjusted life years (QALY) lost due to infections caused by the Respiratory Syncytial Virus (RSV) in children under two years old and their families in Spain). See study.
  • Needs for future pharmacoeconomic analysis of RSV vaccines: Assessing the burden of pediatric RSV disease and QALYs lost. (Phase II: Retrospective study). Objective: Estimate RSV and ALRI rates among children less than 2 years of age in the Valencia Region using Real World Data). See Study.
  • The burden of Respiratory Syncytial Virus A and B, influenza, and RSV Whole- Genome Sequencing in adults: a hospital-based active-surveillance study in 6 consecutive seasons.


  • Risk factors for recurrent wheezing and asthma in association with age and severity of primary RSV infection: A population-based cohort study. Objectives: Analizar la asociación entre la bronquiolitis grave (VRS) y ambulatoria y el riesgo de sibilancias recurrentes y asma. See study.


  • Hospital-based, case-control study of the effectiveness of seasonal influenza vaccine in preventing a laboratory-confirmed influenza virus infection-associated admissions in subjects aged 18 years or older during the 2011-2015 seasons and respiratory virus disease burden in patients of any age admitted to the hospitals included in the study. See study
  • The retrospective database based, cohort study comparing the effects of flu vaccines used in three consecutive campaigns in people 65 years and older.
  • The validity of the Nominal Vaccine Registry to know the vaccination status against influenza in adults admitted to hospitals in the Valencian Community. CSISP-IVE (RVN) -2010-03.
  • Effectiveness of seasonal flu vaccine in preventing income associated with flu virus infection in subjects 18 years of age and older during the 2010-2011 season. Case study and negative controls in the hospital-based RT-PCR test. Spain.
  • Effectiveness of flu vaccines to prevent hospitalisations during the autumn 2009 pandemic wave in Castellón. See Poster.
  • Concordance between ICD discharge diagnosis codes and PCR results: a retrospective analysis using data generated through VAHNSI project from 2010/11 to 2017/18. Objetives: To explore the concordance between influenza ICD codes and LCI. To estimate the percentage of LCI, and not ICD-coded, as influenza.
  • Association between influenza and the risk of cardiovascular disease in the Valencian aging population using Real-World Data. Objective: The overall objective is to estimate the risk of CVD related with influenza in adults aged 50years or older in VR during a nine-year period (January 1st 2010 – December 31st 2018), usingElectronic Healthcare Databases (EHDs). See study.
  • Risk and impact of influenza on patients with diabetes: A population-based study using Real World Data, 2010-2018. Objetivo: The primary objective of the study is to assess the impact of influenza (including health care resources consumption) on the risk and severity of diabetes decompensation and associated complications in adults aged 50 years or older in the Valencia Region (January 1st 2010 to December 31st 2018) using Electronic Healthcare Databases (EHD).
  • Risk of hospitalization and complications associated with influenza among persons with medical chronic conditions. Objetivo: to estimate the seasonal incidence of laboratory confirmed influenza (LCI) associated hospitalizations and of influenza-related complications (IRC) in patients with and without specific chronic conditions (as well as by number of chronic conditions), overall, by age, sex, and influenza vaccination status, and to estimate the relative risk of LCI hospitalizations and IRC in patients with a specific chronic condition (as well as by number of chronic conditions) versus healthyadults (patients without any of the considered comorbidities).


  • Epidemiological study of the prevalence of asymptomatic carriers of meningococcus B in young people and university students in Valencia. Objectives: To estimate the prevalence and risk factors of meningococcus B in young people and university students in Valencia, cross-sectional observational study.
  • Estimation of the impact of a vaccine against meningococcus B in the Region of Valencia. Epidemiological modelling using randomised networks. (Modelling).


  • Population-based seroepidemiological study of meningococcal disease C.
  • Analysis of the relevance of changing the vaccination pattern against Meningococcus C. Epidemiological modelling using randomised networks


  • Impact of the introduction of the quadrivalent human papillomavirus vaccine against genital warts in the Valencian Community.
  • Evaluation study of the acceptance of the vaccine against papillomavirus in the province of Valencia.
  • Estimation of the risk of seizures and syncopes after the administration of the human papillomavirus vaccine in adolescents in the Region of Valencia.
  • Prevalence of human papillomavirus (HPV) in the oral cavity in healthy subjects from 18 to 25 years old in Valencia.
  • HPV vaccines effectiveness to prevent genital warts in Valencia Region, Spain. Objetivo: estimar la efectividad de la vacuna frente VPH en la prevención de verrugas genitales en chicas de 14-19 años. See study.
  • Impact of socio-demographic factors on HPV vaccination in the Valencia Region, Spain: A spatio-temporal approach. Objectives: Analyse the spatio-temporal heterogeneity of HPV vaccination uptake in women born between 1994 and 2006 in the Valencia Region at different geographical levels.


  • Effectiveness of Rotavirus vaccine in preventing hospitalization for acute gastroenteritis in children under 36 months in Valencia, Spain: A retrospective cohort study based on computerized databases.
  • Safety of the rotavirus vaccine in children in the Valencia Region, with special attention to intussusception.
  • Impact of rotavirus vaccines on rotavirus-associated hospitalizations in the Valencia Region, Spain. See study
  • Spatial-temporal impact of Rotavirus vaccine coverage on Rotavirus hospitalizations in the Valencian Community. See Study. 
  • Impact of Rotavirus Vaccination on Acute Gastroenteritis outpatient, and emergency department visits, using “Real World Data” from the Valencia Region, Spain. See study.
  • Impact of rotavirus vaccines on seizures-associated hospitalizations in the Valencia Region, Spain. Objective: analizar el impacto de la vacunación frente a rotavirus en las convulsiones (hospitalizaciones). See study

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  • Use and evaluation of abucasis (SIA-GAIA) as an epidemiological research tool. Incidence of Herpes Zoster in adults. See the graph of the incidence in 2010.                                                                                
  • Analysis of the impact of different vaccination strategies against chickenpox. Pharmaco-economic analysis using randomised network modelling. Objective: To analyse the impact of three vaccination strategies in the Valencia Region: universal child vaccination, vaccination of risk groups and pre-adolescents, and individual non-systemic and pre-adolescent vaccination.

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  • Impact and Risk of Herpes Zoster in immunosuppressed subjects in the Region of Valencia. See Study. 
  • Impact and Risk of Herpes Zoster in diabetics in the Region of Valencia.

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  • Descriptive analysis of schizophrenia and other disorders of the schizophrenic spectrum and their treatment in the Valencian Community. See Study.

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  • Severe COVID-19 infections: automatic, or machine learning, another health care provider in the fight. Objectives:

    1. To study the risk of a specific individual or group developing symptoms of COVID-19 or complications requiring intensive care or dying.
    2. Analyse the benefit (1/risk) of various treatments that have been used compassionately to shorten hospitalisation and avoid mortality.
    3. Analyse the epidemiology of COVID-19 hospitalisations and associated risk factors.
    4. Predict how many patients may require admission to the ICU, how many may require ventilators, and how long patients are likely to stay in the hospital or ICU.