title: HBV immunization and vaccine coverage among hospitalized children in Cameroon, Central African Republic and Senegal: a cross-sectional study.
abstract: BACKGROUND
  Hepatitis B is a major health concern in Africa. The vaccine against hepatitis B virus (HBV) was introduced into the Expanded Programme on Immunization (EPI) of Cameroon and Senegal in 2005, and of CAR (Central African Republic) in 2008. A cross-sectional study was conducted to assess HBV immunization coverage following the vaccine's introduction into the EPI and factors associated with having been vaccinated.
  
  
  METHODS
  All hospitalized children, regardless of the reasons for their hospitalization, between 3 months and 6 years of age, for whom a blood test was scheduled during their stay and whose condition allowed for an additional 2 mL blood sample to be taken, and who provided the parent's written consent were included. All children anti-HBs- and anti-HBc + were tested for HBsAg. Vaccination coverage was assessed in three different ways: immunization card, maternal recall and serologic anti-HBs profile.
  
  
  RESULTS
  1783 children were enrolled between April 2009 and May 2010. An immunization card was only available for 24 % of the children. The median age was 21 months. Overall HBV immunization coverage based on immunization cards was 99 %, 49 % and 100 % in Cameroon, CAR and Senegal, respectively (p < 0,001). The immunization rate based on maternal recall was 91 %, 17 % and 88 % in Cameroon, CAR and Senegal, respectively (p < 0,001). According to serology (anti-HBs titer ≥ 10 mUI/mL and anti-HBc-), the coverage rate was 68 %, 13 % and 46 % in Cameroon, CAR and Senegal, respectively (p < 0,001). In Senegal and Cameroon, factors associated with having been vaccinated were: mother's higher education (OR = 2.2; 95 % CI [1.5-3.2]), no malnutrition (OR = 1.6; 95 % CI [1.1-2.2]), access to flushing toilets (OR = 1.6; 95 % CI [1.1-2.3]), and < 24 months old (OR = 2.1; 95 % CI [1.3-3.4] between 12 and 23 months and OR = 2.7; 95 % CI [1.6-4.4] < 12 months). The prevalence of HBV-infected children (HBsAg+) were 0.7 %, 5.1 %, and 0.2 % in Cameroon, CAR and Senegal, respectively (p < 0.001).
  
  
  CONCLUSIONS
  Assessing immunization coverage based on immunization cards, maternal recall or administrative data could be usefully reinforced by epidemiological data combined with immunological profiles. Serology-based studies should be implemented regularly in African countries, as recommended by the WHO. Malnutrition, lack of maternal education and poverty are factors associated with vaccine non-compliance. The countries' vaccination programs should actively address these problems.
authors.affiliation: Laboratoire des Virus Oncogènes, Institut Pasteur de Bangui, rue Pasteur, BP 923, Bangui, République Centrafricaine. claudinebekondi@yahoo.fr.
authors.forename: Claudine
authors.initials: C
authors.lastname: Bekondi
authors.affiliation: Unité d'Epidémiologie des Maladies Emergentes, Institut Pasteur, 25-28 rue du Docteur Roux, 75015, Paris, France. zanchi.roberta@gmail.com.
authors.forename: Roberta
authors.initials: R
authors.lastname: Zanchi
authors.affiliation: Laboratoire de Biologie Médicale, Institut Pasteur de Dakar, 36 Avenue Pasteur, Dakar, Sénégal. seck@pasteur.sn.
authors.forename: Abdoulaye
authors.initials: A
authors.lastname: Seck
authors.affiliation: Institut Pasteur de Madagascar, BP 1274, Antananarivo, Madagascar. benoit.garin@pasteur.fr.
authors.forename: Benoit
authors.initials: B
authors.lastname: Garin
authors.affiliation: Unité d'Epidémiologie des Maladies Emergentes, Institut Pasteur, 25-28 rue du Docteur Roux, 75015, Paris, France. tamara.giles-vernick@pasteur.fr.
authors.forename: Tamara
authors.initials: T
authors.lastname: Giles-Vernick
authors.affiliation: Services des soins intensifs, Complexe Pédiatrique, BP 911, Bangui, République Centrafricaine. jcgody@hotmail.com.
authors.forename: Jean Chrysotome
authors.initials: JC
authors.lastname: Gody
authors.affiliation: Complexe Pédiatrique, BP 911, Bangui, République Centrafricaine. petubata@yahoo.fr.
authors.forename: Petulla
authors.initials: P
authors.lastname: Bata
authors.affiliation: Centre Mère-Enfant, Fondation Chantal Biya, Yaoundé, Cameroun. pondyangele@yahoo.fr.
authors.forename: Angèle
authors.initials: A
authors.lastname: Pondy
authors.affiliation: Centre Hospitalier d'Essos, Yaoundé, Cameroun. ndiangsuzie@yahoo.fr.
authors.forename: Suzie Moyo
authors.initials: SM
authors.lastname: Tetang
authors.affiliation: Hôpital Albert Royer, Dakar, Sénégal. madouba@gmail.com.
authors.forename: Mamadou
authors.initials: M
authors.lastname: Ba
authors.affiliation: Centre Hospitalier d'Essos, Yaoundé, Cameroun.
authors.forename: Chantal Same
authors.initials: CS
authors.lastname: Ekobo
authors.affiliation: Laboratoire de Virologie, Institut Pasteur Guyane, 23 avenue Pasteur, BP 6010, 97306, Cayenne, France. drousset@pasteur-cayenne.fr.
authors.forename: Dominique
authors.initials: D
authors.lastname: Rousset
authors.affiliation: Département de virologie, Hôpital Saint Louis, Paris, France. jmsire@chi-poissy-st-germain.fr.|Institut National de la Santé et de la Recherche Médicale, Faculté de Médecine Paris-Diderot, Paris, France. jmsire@chi-poissy-st-germain.fr.
authors.forename: Jean-Marie
authors.initials: JM
authors.lastname: Sire
authors.affiliation: Service de Microbiologie CHU St Louis, 75010, Paris, France. sarah.maylin@sls.aphp.fr.
authors.forename: Sarah
authors.initials: S
authors.lastname: Maylin
authors.affiliation: Unité d'Epidémiologie des Maladies Emergentes, Institut Pasteur, 25-28 rue du Docteur Roux, 75015, Paris, France. chartierloic2000@yahoo.fr.
authors.forename: Loïc
authors.initials: L
authors.lastname: Chartier
authors.affiliation: Service de Virologie, Centre Pasteur du Cameroun, P.O.Box 1274, Yaoundé, Cameroun. njouom@pasteur-yaounde.org.
authors.forename: Richard
authors.initials: R
authors.lastname: Njouom
authors.affiliation: Unité d'Epidémiologie des Maladies Emergentes, Institut Pasteur, 25-28 rue du Docteur Roux, 75015, Paris, France. muriel.vray@pasteur.fr.
authors.forename: Muriel
authors.initials: M
authors.lastname: Vray
mesh_terms: D000328:Adult; D000349:Africa / Q000453:epidemiology; D002648:Child; D002673:Child, Hospitalized; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D005260:Female; D006509:Hepatitis B / Q000453:epidemiology* / Q000517:prevention & control; D006510:Hepatitis B Antibodies / Q000097:blood; D006514:Hepatitis B Surface Antigens / Q000097:blood; D017325:Hepatitis B Vaccines / Q000627:therapeutic use*; D006515:Hepatitis B virus / Q000276:immunology; D006801:Humans; D017589:Immunization Programs; D007223:Infant; D008297:Male; D009035:Mothers; D015995:Prevalence; D014611:Vaccination / Q000706:statistics & numerical data
chemical_list: D006510:Hepatitis B Antibodies; D006514:Hepatitis B Surface Antigens; D017325:Hepatitis B Vaccines