title: Partial protection of seasonal trivalent inactivated vaccine against novel pandemic influenza A/H1N1 2009: case-control study in Mexico City.
abstract: OBJECTIVE
  To evaluate the association of 2008-9 seasonal trivalent inactivated vaccine with cases of influenza A/H1N1 during the epidemic in Mexico.
  
  
  METHODS
  Frequency matched case-control study.
  
  
  METHODS
  Specialty hospital in Mexico City, March to May 2009.
  
  
  METHODS
  60 patients with laboratory confirmed influenza A/H1N1 and 180 controls with other diseases (not influenza-like illness or pneumonia) living in Mexico City or the State of Mexico and matched for age and socioeconomic status.
  
  
  METHODS
  Odds ratio and effectiveness of trivalent inactivated vaccine against influenza A/H1N1.
  
  
  RESULTS
  Cases were more likely than controls to be admitted to hospital, undergo invasive mechanical ventilation, and die. Controls were more likely than cases to have chronic conditions that conferred a higher risk of influenza related complications. In the multivariate model, influenza A/H1N1 was independently associated with trivalent inactivated vaccine (odds ratio 0.27, 95% confidence interval 0.11 to 0.66) and underlying conditions (0.15, 0.08 to 0.30). Vaccine effectiveness was 73% (95% confidence interval 34% to 89%). None of the eight vaccinated cases died.
  
  
  CONCLUSIONS
  Preliminary evidence suggests some protection from the 2008-9 trivalent inactivated vaccine against pandemic influenza A/H1N1 2009, particularly severe forms of the disease, diagnosed in a specialty hospital during the influenza epidemic in Mexico City.
authors.affiliation: Instituto Nacional de Salud Pública, Cuernavaca, Mor, Mexico.
authors.forename: Lourdes
authors.initials: L
authors.lastname: Garcia-Garcia
authors.forename: Jose Luis
authors.initials: JL
authors.lastname: Valdespino-Gómez
authors.forename: Eduardo
authors.initials: E
authors.lastname: Lazcano-Ponce
authors.forename: Aida
authors.initials: A
authors.lastname: Jimenez-Corona
authors.forename: Anjarath
authors.initials: A
authors.lastname: Higuera-Iglesias
authors.forename: Pablo
authors.initials: P
authors.lastname: Cruz-Hervert
authors.forename: Bulmaro
authors.initials: B
authors.lastname: Cano-Arellano
authors.forename: Antonio
authors.initials: A
authors.lastname: Garcia-Anaya
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Ferreira-Guerrero
authors.forename: Renata
authors.initials: R
authors.lastname: Baez-Saldaña
authors.forename: Leticia
authors.initials: L
authors.lastname: Ferreyra-Reyes
authors.forename: Samuel
authors.initials: S
authors.lastname: Ponce-de-León-Rosales
authors.forename: Celia
authors.initials: C
authors.lastname: Alpuche-Aranda
authors.forename: Mario Henry
authors.initials: MH
authors.lastname: Rodriguez-López
authors.forename: Rogelio
authors.initials: R
authors.lastname: Perez-Padilla
authors.forename: Mauricio
authors.initials: M
authors.lastname: Hernandez-Avila
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D004196:Disease Outbreaks / Q000517:prevention & control*; D005260:Female; D006801:Humans; D007223:Infant; D053118:Influenza A Virus, H1N1 Subtype; D007252:Influenza Vaccines; D007251:Influenza, Human / Q000150:complications / Q000453:epidemiology / Q000517:prevention & control*; D008297:Male; D008800:Mexico / Q000453:epidemiology; D008875:Middle Aged; D015995:Prevalence; D016896:Treatment Outcome; D015164:Vaccines, Inactivated
chemical_list: D007252:Influenza Vaccines; D015164:Vaccines, Inactivated