Open Access Open Badges Research article

Factors associated with hepatitis B vaccine series completion in a randomized trial for injection drug users reached through syringe exchange programs in three US cities

Sarah Bowman12, Lauretta E Grau3, Merrill Singer45, Greg Scott6 and Robert Heimer3*

Author Affiliations

1 Yale University School of Public Health, New Haven, CT, USA

2 Current address: Department of Emergency Medicine, Rhode Island Hospital, Providence, RI, USA

3 Department of Epidemiology of Microbial Diseases and the Center for Interdisciplinary Research on AIDS, Yale University School of Public Health, New Haven, CT, USA

4 Hispanic Health Council, Hartford, CT, USA

5 Current address: Department of Anthropology, University of Connecticut, Storrs, CT, USA

6 Department of Sociology, DePaul University, Chicago, IL, USA

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BMC Public Health 2014, 14:820  doi:10.1186/1471-2458-14-820

Published: 9 August 2014



Hepatitis B virus (HBV) is a vaccine preventable infection yet vaccination rates are low among injection drug users (IDUs) despite the high risk of infection and longstanding recommendations to promote vaccination. We sought to improve vaccination rates by reaching IDUs through syringe exchange programs (SEPs) in three U.S. cities.


IDUs were randomized in a trial comparing the standard HBV vaccination schedule (0, 1, and 6 months) to an accelerated schedule (0, 1, and 2 months) and participation data were analyzed to identify determinants of completion of the three-dose vaccine series. Independent variables explored included sociodemographics, injection and syringe access behaviors, assessment of health beliefs, HBV-associated knowledge, and personal health status.


Covariates associated with completion of the three-dose vaccine series were accelerated vaccine schedule (aOR 1.92, 95% CI 1.34, 2.58, p = <0.001), older age (aOR 1.05, 95% CI 1.03, 1.07, p = <0.001), and poorer self-rated health score (aOR 1.26, 95% CI 1.05, 1.5, p = 0.02). Completion was less likely for those getting syringes from SEP customers than for SEP customers (OR 0.33, 95% CI 0.19, 0.58, p = <0.001).


SEPs should offer hepatitis vaccination in a manner that minimizes time between first and last visits by accelerating the dosing schedule. Public health interventions should target younger, less healthy, and non-SEP customer participants. Other health interventions at SEPs may benefit from similar approaches that reach out beyond regular SEP customers.

Hepatitis B; Vaccination; Syringe exchange programs; Injection drug users