title: [Flu vaccine effectiveness: a metaanalysis].
abstract: BACKGROUND
  Seasonal influenza is a disease of great interest in public health due to its high rates of infection and big costs, especially in high-risk population. This situation has motivated studies related to development of control measures necessary to mitigate its impact. Immunization constitutes a key role in providing the necessary interventions; however, little information is available about its effectiveness as public health measure in tropical countries.
  
  
  OBJECTIVE
  The vaccine effectiveness was evaluated by means of published results in the scientific literature.
  
  
  METHODS
  Meta-analysis techniques were used to summarize the results of epidemiological analytical studies. A critical evaluation was undertaken for each study to identify the potential biases and methodological limitations.
  
  
  RESULTS
  Two hundred and fifty-seven relevant studies were located, of which 28 were included in the analysis. The pooled estimator of the vaccine effectiveness for hospitalization was 0.74 [95% CI 0.68-0.81] in older adults (65 years and older) in cases-control studies. For cohort studies, the obtained estimator was 0.80 [95% CI 0.68-0.91].
  
  
  CONCLUSIONS
  Other conclusions were analyzed, and in general, a protective effect was demonstrated in the vaccine. About 1,200,000 were involved, 530,000 of them were vaccinated. Geographically, the analyzed studies came from developed countries in Europe, America and Asia.
authors.affiliation: Grupo de Epidemiología, Subdirección de Investigaciones, Instituto Nacional de Salud, Bogotá D.C., Colombia. josemorenomontoya@gmail.com
authors.forename: José
authors.initials: J
authors.lastname: Moreno
authors.forename: Fernando
authors.initials: F
authors.lastname: De la Hoz
authors.forename: Alejandro
authors.initials: A
authors.lastname: Rico
authors.forename: Karol
authors.initials: K
authors.lastname: Cotes
authors.forename: Alexandra
authors.initials: A
authors.lastname: Porras
mesh_terms: D000367:Age Factors; D000368:Aged; D016022:Case-Control Studies; D015331:Cohort Studies; D005069:Evaluation Studies as Topic; D005260:Female; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D007223:Infant; D007252:Influenza Vaccines; D007251:Influenza, Human / Q000453:epidemiology / Q000517:prevention & control*; D008297:Male
chemical_list: D007252:Influenza Vaccines