title: Persistence of seroprotection 10 years after primary hepatitis A vaccination in an unselected study population.
abstract: Hepatitis A vaccines have been demonstrated to be highly immunogenic. Mathematical models have predicted antibodies to persist for at least 20-25 years. Most of these studies have been conducted in young and healthy study populations. We aimed to evaluate long-term immunity 10 years following complete primary immunization according to a 3-dose schedule (Havrix 720 El.U at months 0, 1, 6-12) in an adult and unselected study population. In total, 999 (98.3%) of 1016 vaccinees (mean age 54.7+/-S.D. 13.0), tested 10 years after primary vaccination, still had protective antibody levels (> or = 10 mIU/ml) as measured by ELISA. An anti-HAV titer cut off level of 11,400 mIU/ml was calculated to differentiate between vaccine-induced and infection-induced titer levels. The vaccine-induced geometric mean titer (GMT) was 406.1 mIU/ml (95% CI: 369.2-446.7 mIU/ml), showing an age-related trend, the 10-years seroprotection rate (SPR) was 97.9%. Females exhibited significantly higher GMTs than male vaccinees (p<0.001). The only parameter predicting a titer below 10 mIU/ml 10 years after vaccination was the body mass index (p=0.001). This study confirms that protection following primary hepatitis A vaccination persists for more than 10 years.
authors.affiliation: Department of Specific Prophylaxis and Tropical Medicine, Center for Physiology and Pathophysiology, Medical University Vienna, Vienna, Austria.
authors.forename: Pamela
authors.initials: P
authors.lastname: Rendi-Wagner
authors.forename: Maria
authors.initials: M
authors.lastname: Korinek
authors.forename: Birgit
authors.initials: B
authors.lastname: Winkler
authors.forename: Michael
authors.initials: M
authors.lastname: Kundi
authors.forename: Herwig
authors.initials: H
authors.lastname: Kollaritsch
authors.forename: Ursula
authors.initials: U
authors.lastname: Wiedermann
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D005260:Female; D035922:Hepatitis A Antibodies / Q000097:blood*; D022362:Hepatitis A Vaccines / Q000276:immunology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012737:Sex Factors; D013997:Time Factors; D014611:Vaccination
chemical_list: D035922:Hepatitis A Antibodies; D022362:Hepatitis A Vaccines