title: Impact of Hepatitis A vaccination with a two-dose schedule in Panama: Results of epidemiological surveillance and time trend analysis.
abstract: OBJECTIVE
  In April 2007, Panama introduced Hepatitis A universal vaccination using a two-dose schedule (Havrix(®)junior; GSK Vaccines, Belgium). We assessed the impact of this hepatitis A vaccine three years after it was recommended for universal mass vaccination in Panama.
  
  
  METHODS
  Hepatitis A vaccination impact was assessed using two different approaches. The first approach used retrospective data (incidence and number of cases for all age groups), collected from the passive surveillance of the Epidemiologic Surveillance System of the Ministry of Health of hepatitis A and unspecified hepatitis before (2000-2006) and after (2008-2010) introduction of hepatitis A vaccine. The second approach was a prospective hospital-based active surveillance for hepatitis cases conducted in subjects (0-14 years) during 2009-2011 at three sentinel hospitals in Panama.
  
  
  RESULTS
  Overall, the annual incidence of hepatitis A and unspecified hepatitis in 2008, 2009 and 2010 were 13.1, 7.9 and 3.7 per 100,000 subjects, lower than the baseline incidence of 51.1 per 100,000 subjects. In comparison to the mean baseline period (2000-2006), there was an 82% mean reduction in the overall hepatitis-related outcomes (hepatitis A and unspecified hepatitis) after vaccine introduction (2008-2010) in all age groups. In the hospital-based surveillance (2009-2011), of the 42 probable viral hepatitis A cases, nine cases were confirmed as acute hepatitis A (8 in 2009, 1 in 2010). Of these confirmed cases, two belonged to the targeted vaccine group (1-4 years) but were not vaccinated.
  
  
  CONCLUSIONS
  Our study suggests that the introduction of two-dose hepatitis A vaccines in Panama has contributed to the reduction in the incidence of overall hepatitis-related outcomes for all age groups, suggesting herd protection. Additional monitoring is required to document a sustained long-term effect.
authors.affiliation: Hospital del Niño Panama, Panama City, Panama. Electronic address: destripeaut@gmail.com.
authors.forename: Dora
authors.initials: D
authors.lastname: Estripeaut
authors.affiliation: Instituto Conmemorativo Gorgas de Estudios de la Salud, Panama City, Panama.
authors.forename: Rodolfo
authors.initials: R
authors.lastname: Contreras
authors.affiliation: Instituto de Investigaciones Científicas y Servicios de Alta Tecnología (INDICASAT), Panama City, Panama.
authors.forename: Olga
authors.initials: O
authors.lastname: Tinajeros
authors.affiliation: GSK Vaccines, CARICAM ANDINA, Panama City, Panama.
authors.forename: Maria Mercedes
authors.initials: MM
authors.lastname: Castrejón
authors.affiliation: GSK Pharmaceuticals Limited, Bangalore, India.
authors.forename: Fakrudeen
authors.initials: F
authors.lastname: Shafi
authors.affiliation: GSK Vaccines, LATAM, Panama City, Panama.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Ortega-Barria
authors.affiliation: GSK Vaccines, LATAM, Bogotá, Colombia.
authors.forename: Rodrigo
authors.initials: R
authors.lastname: DeAntonio
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D062665:Epidemiological Monitoring; D005260:Female; D006506:Hepatitis A / Q000453:epidemiology / Q000517:prevention & control*; D022362:Hepatitis A Vaccines / Q000008:administration & dosage* / Q000276:immunology; D006801:Humans; D032521:Immunity, Herd; D007115:Immunization Schedule; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D010176:Panama / Q000453:epidemiology; D011446:Prospective Studies; D012189:Retrospective Studies; D013997:Time Factors; D000637:Transaminases / Q000097:blood; D014611:Vaccination / Q000706:statistics & numerical data* / Q000639:trends
chemical_list: D022362:Hepatitis A Vaccines; D000637:Transaminases; C019798:branched-chain-amino-acid transaminase
keywords: Havrix(®)junior; Hepatitis A virus; NCT01159925, NCT01159951 (www.clinicaltrials.gov); Panama; Vaccination