People who inject drugs and are positive for hepatitis C antibodies are more susceptible to hepatitis A virus and hepatitis B virus infections due to low vaccine coverage, according to a study published in Public Health Reports.
The aim of this study was to assess hepatitis A virus and hepatitis B virus vaccine coverage for people who live in Wisconsin, inject drugs, and had a positive hepatitis C virus antibody test. Data were collected from the syringe services program, to identify people who had a positive hepatitis C virus antibody test and who use or have used injection drugs, as well as from the Wisconsin Immunization Registry, to identify vaccination history. Participants were matched between the registries using an exact match of first and last name and birth date.
Of the 204 people included in this study, the median age was 31 years old, 54.4% were men, 83.3% were white, 80.9% reported injecting drugs within the past 6 months, and 86.8% reported a history of incarceration. Overall, 72.1% had received ≥1 dose of either vaccine, 32.4% had received ≥1 dose of hepatitis A vaccine, 22.5% had received 2 doses of hepatitis A vaccine, 56.4% had received 3 doses of hepatitis B vaccine, and 16.7% had completed both vaccine series. For hepatitis A vaccine, the median age at completion was 29 years and for hepatitis B vaccine, the median age at completion was 11 years.
For the hepatitis A vaccine, the study population and the general population had similar coverage rated for people aged 20 to 29 years, but the study population had higher rates of coverage for people aged 30 to 49 compared with the general population. For the hepatitis B vaccine, coverage rates were similar between the study population and the general population, but coverage decreased with an increase in age, from 88% in people aged 20 to 24 years to 30.3% in people aged 35 to 39 years.
Limitations of this study included a potential bias by only including people with positive hepatitis C virus antibody tests, by not assessing immunity to hepatitis A virus and hepatitis B virus infections, and potentially missing data from the Wisconsin Immunization Registry that could lead to underestimates.
The researchers concluded, “that most persons who inject drugs in Wisconsin are susceptible to [hepatitis A virus] infection and that most persons aged ≥35 who inject drugs are susceptible to [hepatitis B virus] infection.”
Koepke R, Sill DN, Akhtar WZ, et al. Hepatitis A and hepatitis B vaccination coverage among persons who inject drugs and have evidence of hepatitis C infection [published online Sept. 20, 2019]. Public Health Rep. doi: 10.1177/0033354919874088