Social-cognitive determinants of vaccination behavior against hepatitis B: an assessment among men who have sex with men John B.F. de Wit, Ph.D. a, * , Raymond Vet M.Sc. a , Merel Schutten, M.Sc. b , Jim van Steenbergen, Ph.D. c a Department of Social and Organisational Psychology, Utrecht University, PO Box 80.140, 3508 TC Utrecht, The Netherlands b Addiction Research Institute Foundation, Rotterdam, The Netherlands c National Coordinator Infectious Disease Control and Amsterdam Municipal Health Service, The Netherlands Available online 5 November 2004 Abstract Background. Many individuals who are at risk for infection with the hepatitis B virus (HBV), including men who have sex with men (MSM), are not vaccinated. This study assessed social-cognitive determinants of obtaining vaccination against HBV. Methods. A targeted survey was conducted among 432 MSM by means of a written questionnaire that contained assessments of social- cognitive determinants of vaccination behavior derived from the Health Belief Model (HBM) and the Theory of Planned Behavior. Vaccination behavior was anonymously linked to questionnaire data for which informed consent was obtained. Results. Of the 290 men eligible for vaccination, 248 (86%) had obtained vaccination. Multivariate logistic regression analysis showed that these men were younger, more often were in a steady relationship, and had fewer sex partners. In addition, significant effects were also found for central factors proposed by the Health Belief Model. Notably, men who obtained vaccination against HBV perceived more personal threat from HBV. None of the Theory of Planned Behavior variables were related to obtaining vaccination. Conclusions. Findings suggest that health education interventions that address perceived susceptibility and severity are likely to contribute to increased uptake of HBV vaccination among MSM. Influencing perceived susceptibility in particular is important, more so than increasing perceived severity by scare tactics. D 2004 Elsevier Inc. All rights reserved. Keywords: Homosexual men; Hepatitis B virus; Vaccination; Social-cognitive determinants; Health behavior; Prevention Introduction Hepatitis B infection is a viral sexually transmitted disease (STD) that is caused by the hepatitis B virus (HBV), which nestles itself in the liver cells of the body and can be transmitted through blood contact and sperm [1]. Hepatitis B infection mostly recovers by itself, but it is possible that the infection becomes chronic and occasionally death can occur as a result from lasting damage to the liver [1]. About 10% of the infected individuals remain infected for the rest of their lives (so-called bcarriersQ) and are infectious to others [1]. Because recovering from HBV is difficult and not always possible, prevention of infection is of crucial importance. Elimination strategies include prevention of perinatal transmission, routine infant vaccination, catch-up vaccination of children in high-risk groups at any age, catch- up vaccination of all children at 11–12 years of age, and vaccination of adolescents and adults in high-risk groups [2]. Vaccination against the virus can offer protection for more than 15 years, and therefore appears to be the most effective way of preventing infection [3]. In the US and Europe, substantial progress has been made in implementing routine infant hepatitis B [4,5], and by the mid-1990s, more than half of the reported acute infections in the US occurred among young adults in high- risk groups [4]. Among the bclassic risk groupsQ for infection with HBV are intravenous drug users and heterosexuals with multiple sex partners, including sex 0091-7435/$ - see front matter D 2004 Elsevier Inc. All rights reserved. doi:10.1016/j.ypmed.2004.09.026 * Corresponding author. Fax: +31 30 2534718. E-mail address: j.b.f.dewit@fss.uu.nl (J.B.F. de Wit). Preventive Medicine 40 (2005) 795 – 802 www.elsevier.com/locate/ypmed