title: Respiratory virus infection and risk of invasive meningococcal disease in central Ontario, Canada.
abstract: BACKGROUND
  In temperate climates, invasive meningococcal disease (IMD) incidence tends to coincide with or closely follow peak incidence of influenza virus infection; at a seasonal level, increased influenza activity frequently correlates with increased seasonal risk of IMD.
  
  
  METHODS
  We evaluated 240 cases of IMD reported in central Ontario, Canada, from 2000 to 2006. Associations between environmental and virological (influenza A, influenza B and respiratory syncytial virus (RSV)) exposures and IMD incidence were evaluated using negative binomial regression models controlling for seasonal oscillation. Acute effects of weekly respiratory virus activity on IMD risk were evaluated using a matched-period case-crossover design with random directionality of control selection. Effects were estimated using conditional logistic regression.
  
  
  RESULTS
  Multivariable negative binomial regression identified elevated IMD risk with increasing influenza A activity (per 100 case increase, incidence rate ratio = 1.18, 95% confidence interval (CI): 1.06, 1.31). In case-crossover models, increasing weekly influenza A activity was associated with an acute increase in the risk of IMD (per 100 case increase, odds ratio (OR)  = 2.03, 95% CI: 1.28 to 3.23). Increasing weekly RSV activity was associated with increased risk of IMD after adjusting for RSV activity in the previous 3 weeks (per 100 case increase, OR = 4.31, 95% CI: 1.14, 16.32). No change in disease risk was seen with increasing influenza B activity.
  
  
  CONCLUSIONS
  We have identified an acute effect of influenza A and RSV activity on IMD risk. If confirmed, these finding suggest that influenza vaccination may have the indirect benefit of reducing IMD risk.
authors.affiliation: Dalla Lana School of Public Health, University of Toronto, Toronto, Canada.
authors.forename: Ashleigh R
authors.initials: AR
authors.lastname: Tuite
authors.forename: Laura M
authors.initials: LM
authors.lastname: Kinlin
authors.forename: Stefan P
authors.initials: SP
authors.lastname: Kuster
authors.forename: Frances
authors.initials: F
authors.lastname: Jamieson
authors.forename: Jeffrey C
authors.initials: JC
authors.lastname: Kwong
authors.forename: Allison
authors.initials: A
authors.lastname: McGeer
authors.forename: David N
authors.initials: DN
authors.lastname: Fisman
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002675:Child, Preschool; D015897:Comorbidity / Q000639:trends; D005260:Female; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D009980:Influenza A virus / Q000302:isolation & purification; D009981:Influenza B virus / Q000302:isolation & purification; D007251:Influenza, Human / Q000453:epidemiology* / Q000821:virology; D016015:Logistic Models; D008297:Male; D008589:Meningococcal Infections / Q000453:epidemiology*; D008875:Middle Aged; D015999:Multivariate Analysis; D016017:Odds Ratio; D009864:Ontario / Q000453:epidemiology; D012136:Respiratory Syncytial Viruses / Q000302:isolation & purification; D012141:Respiratory Tract Infections / Q000139:chemically induced / Q000453:epidemiology*; D012621:Seasons; D055815:Young Adult