Factors associated to duration of hepatitis a outbreaks: implications for control

PLoS One. 2012;7(2):e31339. doi: 10.1371/journal.pone.0031339. Epub 2012 Feb 15.

Abstract

Even though hepatitis A mass vaccination effectiveness is high, outbreaks continue to occur. The aim of this study was to investigate the association between duration and characteristics of hepatitis A outbreaks. Hepatitis A (HA) outbreaks reported between 1991 and 2007 were studied. An outbreak was defined as ≥2 epidemiologically-linked cases with ≥1 case laboratory-confirmed by detection of HA immunoglobulin M (IgM) antibodies. Relationships between explanatory variables and outbreak duration were assessed by logistic regression. During the study period, 268 outbreaks (rate 2.45 per million persons-year) and 1396 cases (rate 1.28 per 10(5) persons-year) were reported. Factors associated with shorter duration were time to intervention (OR = 0.96; 95% CI: 0.94-0.98) and school setting (OR = 0.39; 95% CI: 0.16-0.92). In person-to-person transmission outbreaks only time to intervention was associated with shorter outbreak duration (OR = 0.96; 95% CI: 0.95-0.98). The only variables associated with shorter outbreak duration were early administration of IG or vaccine and a school setting. Timely reporting HA outbreaks was associated with outbreak duration. Making confirmed HA infections statutory reportable for clinical laboratories could diminish outbreak duration.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Child
  • Communicable Disease Control / organization & administration*
  • DNA, Viral / genetics
  • Disease Outbreaks / prevention & control*
  • Female
  • Hepatitis A / diagnosis*
  • Hepatitis A / epidemiology
  • Hepatitis A / transmission*
  • Hepatitis A Antibodies / blood
  • Hepatitis A Vaccines / therapeutic use
  • Hepatitis A virus / genetics
  • Hepatitis A virus / isolation & purification
  • Hepatitis A virus / pathogenicity*
  • Humans
  • Male
  • Population Surveillance
  • Risk Factors
  • Schools
  • Spain / epidemiology
  • Time Factors

Substances

  • DNA, Viral
  • Hepatitis A Antibodies
  • Hepatitis A Vaccines