title: Factors associated to duration of hepatitis a outbreaks: implications for control.
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.
authors.affiliation: Department of Health. Generalitat of Catalonia. Barcelona, Spain. nuria.torner@gencat.cat
authors.forename: Nuria
authors.initials: N
authors.lastname: Torner
authors.forename: Sonia
authors.initials: S
authors.lastname: Broner
authors.forename: Ana
authors.initials: A
authors.lastname: Martinez
authors.forename: Cecilia
authors.initials: C
authors.lastname: Tortajada
authors.forename: Patricia
authors.initials: P
authors.lastname: Garcia de Olalla
authors.forename: Irene
authors.initials: I
authors.lastname: Barrabeig
authors.forename: MariaRosa
authors.initials: M
authors.lastname: Sala
authors.forename: Neus
authors.initials: N
authors.lastname: Camps
authors.forename: Sofia
authors.initials: S
authors.lastname: Minguell
authors.forename: Josep
authors.initials: J
authors.lastname: Alvarez
authors.forename: Gloria
authors.initials: G
authors.lastname: Ferrús
authors.forename: Roser
authors.initials: R
authors.lastname: Torra
authors.forename: Pere
authors.initials: P
authors.lastname: Godoy
authors.forename: Angela
authors.initials: A
authors.lastname: Dominguez
mesh_terms: D002648:Child; D003140:Communicable Disease Control / Q000458:organization & administration*; D004279:DNA, Viral / Q000235:genetics; D004196:Disease Outbreaks / Q000517:prevention & control*; D005260:Female; D006506:Hepatitis A / Q000175:diagnosis* / Q000453:epidemiology / Q000635:transmission*; D035922:Hepatitis A Antibodies / Q000097:blood; D022362:Hepatitis A Vaccines / Q000627:therapeutic use; D030041:Hepatitis A virus / Q000235:genetics / Q000302:isolation & purification / Q000472:pathogenicity*; D006801:Humans; D008297:Male; D011159:Population Surveillance; D012307:Risk Factors; D012574:Schools; D013030:Spain / Q000453:epidemiology; D013997:Time Factors
chemical_list: D004279:DNA, Viral; D035922:Hepatitis A Antibodies; D022362:Hepatitis A Vaccines