title: Impact of Statins on Influenza Vaccine Effectiveness Against Medically Attended Acute Respiratory Illness.
abstract: BACKGROUND
  Statins have antiinflammatory effects that may impact vaccine-induced immune responses. We investigated the impact of statin therapy on influenza vaccine effectiveness (VE) against medically attended acute respiratory illness (MAARI).
  
  
  METHODS
  We conducted a retrospective cohort study over nine influenza seasons using research databases of a large managed care organization in the United States. Influenza vaccination and statin prescription statuses of cohort members and MAARI cases were ascertained on a per-season basis. Incidence rate ratios (IRRs) of MAARI were estimated using Poisson regression and stratified by statin use. Using a ratio of ratios approach, we compared IRRs from periods during to IRRs from periods before influenza circulation and then used relative IRRs to compute VE.
  
  
  RESULTS
  After adjustment for multiple prespecified covariates, the influenza VE against MAARI was lower among statin users than nonusers during periods of local (14.1% vs 22.9%; mean difference, 11.4%; 95% confidence interval [CI], -1.7% to 26.1%) and widespread (12.6% vs 26.2%; mean difference, 18.4%; 95% CI, 2.9%-36.2%) influenza circulation.
  
  
  CONCLUSIONS
  In this study, statin therapy was associated with reduced influenza VE against MAARI. Since many cases of MAARI are not caused by influenza, studies of the impact of statins on influenza VE against laboratory-confirmed influenza are needed.
authors.affiliation: Hubert Department of Global Health Department of Epidemiology, Rollins School of Public Health Department of Pediatrics Emory Vaccine Center, Emory University, Atlanta, Georgia.
authors.forename: Saad B
authors.initials: SB
authors.lastname: Omer
authors.affiliation: Division of Infectious Diseases, School of Medicine.
authors.forename: Varun K
authors.initials: VK
authors.lastname: Phadke
authors.affiliation: Hubert Department of Global Health Emory Vaccine Center, Emory University, Atlanta, Georgia.
authors.forename: Robert A
authors.initials: RA
authors.lastname: Bednarczyk
authors.affiliation: Department of Epidemiology, Rollins School of Public Health.
authors.forename: Allison T
authors.initials: AT
authors.lastname: Chamberlain
authors.affiliation: Department of Epidemiology, Rollins School of Public Health.
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Brosseau
authors.affiliation: Hubert Department of Global Health Department of Pediatrics Emory Vaccine Center, Emory University, Atlanta, Georgia.
authors.forename: Walter A
authors.initials: WA
authors.lastname: Orenstein
mesh_terms: D000208:Acute Disease; D000368:Aged; D000893:Anti-Inflammatory Agents / Q000009:adverse effects*; D004347:Drug Interactions; D005260:Female; D006801:Humans; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors / Q000009:adverse effects*; D007252:Influenza Vaccines / Q000276:immunology*; D007251:Influenza, Human / Q000453:epidemiology / Q000276:immunology / Q000517:prevention & control*; D008297:Male; D008875:Middle Aged; D012141:Respiratory Tract Infections / Q000453:epidemiology / Q000276:immunology*; D012189:Retrospective Studies
chemical_list: D000893:Anti-Inflammatory Agents; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors; D007252:Influenza Vaccines
keywords: inflammation; influenza; medically attended acute respiratory illness; statin; vaccine effectiveness