title: Sudden-Onset Sensorineural Hearing Loss after Immunization: A Case-Centered Analysis.
abstract: Case reports of sudden sensorineural hearing loss (SSHL) following vaccines have led to concerns that vaccines may rarely cause hearing loss. Because of this concern, we analyzed for an association between SSHL and vaccinations.
  
  
  
  We used a case-centered method, equivalent to a case control design using immunization dates from all matched members of the population to calculate exposure to vaccines, rather than sampling.
  
  
  
  Kaiser Permanente Northern California (KPNC), 2007 to 2013.
  
  
  
  We searched KPNC databases from 2007 to 2013 for all first-time diagnoses of SSHL. We used the date of any hearing- or ear-related visit in the 60 days prior to the first SSHL diagnosis as the onset date. Using only SSHL cases immunized in the prior 9 months, we compared the vaccine exposure in several risk intervals prior to onset with the exposure to the same vaccine during the same time period in all KPNC membership, matched to sex and age.
  
  
  
  During the study period, >20 million vaccines were administered at KPNC. In all risk intervals prior to onset of SSHL, we found no evidence of increased risk of immunization compared with matched controls. The odds ratios for vaccination 1 week prior to SSHL were 0.965 (95% confidence interval, 0.61-1.50) for trivalent inactivated influenza vaccine (TIV); 0.842 (0.39-1.62) for tetanus, reduced diphtheria, and reduced acellular pertussis; and 0.454 (0.08-1.53) for zoster vaccine.
  
  
  
  A large-scale analysis applying a case-centered method did not detect any association between SSHL and previous receipt of TIV or other vaccines.
authors.affiliation: Northern California Kaiser Permanente Vaccine Study Center, Oakland, California, USA roger.baxter@kp.org.
authors.forename: Roger
authors.initials: R
authors.lastname: Baxter
authors.affiliation: Northern California Kaiser Permanente Vaccine Study Center, Oakland, California, USA.
authors.forename: Ned
authors.initials: N
authors.lastname: Lewis
authors.affiliation: The Permanente Medical Group, Santa Rosa, California, USA.
authors.forename: Pamela
authors.initials: P
authors.lastname: Bohrer
authors.affiliation: CDC, Division of Healthcare Quality Promotion, Immunization Safety Office, Atlanta, Georgia, USA.
authors.forename: Theresa
authors.initials: T
authors.lastname: Harrington
authors.affiliation: Northern California Kaiser Permanente Vaccine Study Center, Oakland, California, USA.
authors.forename: Laurie
authors.initials: L
authors.lastname: Aukes
authors.affiliation: Northern California Kaiser Permanente Vaccine Study Center, Oakland, California, USA.
authors.forename: Nicola P
authors.initials: NP
authors.lastname: Klein
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D006319:Hearing Loss, Sensorineural / Q000209:etiology*; D003639:Hearing Loss, Sudden / Q000209:etiology*; D006801:Humans; D007252:Influenza Vaccines / Q000009:adverse effects*; D008297:Male
chemical_list: D007252:Influenza Vaccines
keywords: adverse event; hearing loss; immunization; influenza vaccine; sensorineural; vaccine