Hepatitis A seroprevalence and risk factors among homeless adults in San Francisco: should homelessness be included in the risk-based strategy for vaccination?
OBJECTIVE
Homeless adults have an increased risk of infectious diseases due to sexual and drug-related behaviors and substandard living conditions. We investigated the prevalence and risk factors for presence of hepatitis A virus (HAV) antibodies among homeless and marginally housed adults.


METHODS
We analyzed serologic and questionnaire data from a study of marginally housed and homeless adults in San Francisco from April 1999 to March 2000. We tested seroprevalance for total antibodies to HAV (anti-HAV) and analyzed data using Chi-square tests and logistic regression.


RESULTS
Of the 1,138 adults in the study, 52% were anti-HAV positive. The anti-HAV prevalence in this study population was 58% higher than the expected prevalence based on age-specific prevalence rates from the general population. Number of years of homelessness (< or =1, 2-4, and > or =5 years) was associated with anti-HAV prevalence (46%, 50%, and 61%, respectively, p < 0.001). We found other differences in anti-HAV prevalence (p < 0.05) for ever having injected drugs (63% vs. 42% for non-injectors), being foreign-born (75% vs. 51% among U.S.-born), race/ethnicity (72%, 53%, and 45% for Hispanic, white, and black people, respectively), and increasing age (38%, 49%, and 62% among those aged <35, 35-45, and >45 years, respectively). These variables all remained significant in a multivariate model.


CONCLUSIONS
We found overall anti-HAV prevalence elevated in this San Francisco homeless population compared with the general U.S. population. These data show that anti-HAV was associated with homelessness independent of other known risk factors, such as being foreign-born, race/ethnicity, and injection drug use. This increase indicates an excess risk of HAV infection and the potential need to offer hepatitis A vaccination as part of homeless services.
Hennessey
Karen A
KA
Centers for Disease Control and Prevention, Division of Viral Hepatitis, Atlanta, GA 30333, USA. keh7@cdc.gov
Bangsberg
David R
DR
Weinbaum
Cindy
C
Hahn
Judith A
JA
D000328:Adult; D005260:Female; D006506:Hepatitis A / Q000453:epidemiology* / Q000517:prevention & control; D035922:Hepatitis A Antibodies / Q000097:blood; D006703:Ill-Housed Persons / Q000706:statistics & numerical data; D006801:Humans; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D012309:Risk-Taking; D012495:San Francisco / Q000453:epidemiology; D016036:Seroepidemiologic Studies; D014611:Vaccination
D035922:Hepatitis A Antibodies