title: Incidence rates and risk factors for owner-reported adverse events following vaccination of dogs that did or did not receive a Leptospira vaccine.
abstract: OBJECTIVE
  To determine incidence rates (IRs) and potential risk factors for owner-reported adverse events (AEs) following vaccination of dogs that did or did not receive a Leptospira vaccine.
  
  
  METHODS
  Observational, retrospective cohort study.
  
  
  METHODS
  130,557 dogs.
  
  
  METHODS
  Electronic records of mobile veterinary clinics from June 2012 to March 2013 were searched to identify dogs that received ≥ 1 vaccine in a given visit. Signalment data, vaccinations received, medications administered, and owner-reported clinical signs consistent with AEs that developed ≤ 5 days after vaccination were recorded. Associations between potential risk factors and owner-reported AEs were evaluated by logistic regression analysis.
  
  
  RESULTS
  The IR/10,000 dogs for owner-reported postvaccination AEs was 26.3 (95% CI, 23.6 to 29.2), whereas that for dogs that received a Leptospira vaccine alone or with other vaccines was 53.0 (95% CI, 42.8 to 64.9). Significant factors for increasing or decreasing risk of AEs were as follows: receiving a Leptospira vaccine (adjusted OR, 2.13), age at vaccination 1 to < 7 or ≥ 7 years (vs a referent of < 6 months; adjusted OR, 0.54 and 0.44, respectively), and weight 13.6 to < 22.7 kg (30 to < 50 lb) and 22.7 to < 45.5 kg (50 to 100 lb [vs a referent of < 4.5 kg {10 lb}]; adjusted OR, 0.48 and 0.55, respectively). Hypersensitivity reactions were rare (IR, 6.5/10,000 dogs), and IRs for these events did not differ significantly between dogs vaccinated with or without a Leptospira component.
  
  
  CONCLUSIONS
  The overall IR for owner-reported postvaccination AEs was low. Results suggested vaccination against Leptospira (an organism that can cause fatal disease) is safe in the majority of cases, slightly increasing the risk of owner-reported AEs but not associated with a significant increase in hypersensitivity reactions, compared with other vaccinations administered.
authors.forename: Peng Ju
authors.initials: PJ
authors.lastname: Yao
authors.forename: Nicole
authors.initials: N
authors.lastname: Stephenson
authors.forename: Janet E
authors.initials: JE
authors.lastname: Foley
authors.forename: Chuck R
authors.initials: CR
authors.lastname: Toussieng
authors.forename: Thomas B
authors.initials: TB
authors.lastname: Farver
authors.forename: Jane E
authors.initials: JE
authors.lastname: Sykes
authors.forename: Katryna A
authors.initials: KA
authors.lastname: Fleer
mesh_terms: D000818:Animals; D001428:Bacterial Vaccines / Q000008:administration & dosage / Q000009:adverse effects*; D004283:Dog Diseases / Q000139:chemically induced* / Q000453:epidemiology; D004285:Dogs; D005260:Female; D007919:Leptospira / Q000276:immunology*; D008297:Male; D016017:Odds Ratio; D012189:Retrospective Studies; D012307:Risk Factors; D014481:United States / Q000453:epidemiology
chemical_list: D001428:Bacterial Vaccines