title: Primary Hepatitis A vaccination failure is a rare although possible event: results of a retrospective study.
abstract: A case of Hepatitis A occurred in a traveller in spite of a complete course of immunization with a combined HAV and HBV vaccine [Taliani G, Sbaragli S, Bartoloni A, Santini MG, Tozzi A, Paradisi F. Hepatitis A vaccine failure: how to treat the threat. Vaccine 2003;21(31):4505-6]. A retrospective study was performed to evaluate whether the failure was primary or could be attributed to a specific lot of vaccine or to its inadequate handling and/or storage. Two distinct populations of vaccinees were selected in a 1:2 proportion. The case group (N=31) included subjects who were vaccinated in the same period and with the same lot and batch of vaccine as the case. The control group (N=62) included subjects who received different lot and batch of the same vaccine as the case group. A persisting antibody response to HAV vaccine was found among all subjects (anti-HAV >20mIU/ml). The overall anti-HBs seropositivity rate (anti-HBs >10mIU/ml) was 74%, without significant difference between the case (77%) and the control group (73%; P>0.05). The reported Hepatitis A case can be attributed to a rare primary vaccine failure rather than to inefficacy of a specific lot of vaccine or to inappropriate vaccine handling or storage. Our study supports the indications for use of combined Hepatitis A+B immunization in travellers at risk for both infections, but stresses the need for information on correct hygienic behaviours while abroad.
authors.affiliation: Department of Public Health, University of Florence, Firenze, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Bonanni
authors.forename: Angela
authors.initials: A
authors.lastname: Bechini
authors.forename: Giovanna
authors.initials: G
authors.lastname: Pesavento
authors.forename: Rosalba
authors.initials: R
authors.lastname: Guadagno
authors.forename: Maria Grazia
authors.initials: MG
authors.lastname: Santini
authors.forename: Simonetta
authors.initials: S
authors.lastname: Baretti
authors.forename: Alessandro
authors.initials: A
authors.lastname: Bartoloni
authors.forename: Gloria
authors.initials: G
authors.lastname: Taliani
mesh_terms: D016022:Case-Control Studies; D006506:Hepatitis A / Q000209:etiology; D035922:Hepatitis A Antibodies / Q000097:blood*; D022362:Hepatitis A Vaccines / Q000592:standards*; D017957:Hepatitis A Virus, Human / Q000276:immunology*; D006510:Hepatitis B Antibodies / Q000097:blood*; D017325:Hepatitis B Vaccines / Q000592:standards*; D006801:Humans; D012189:Retrospective Studies
chemical_list: D035922:Hepatitis A Antibodies; D022362:Hepatitis A Vaccines; D006510:Hepatitis B Antibodies; D017325:Hepatitis B Vaccines