Selected and summarized by Ronald O. Valdiserri, MD, MPH, Professor, Department of Epidemiology, Rollins School of Public Health, Emory University, and Co-Chair of HepVu.
Dr. Valdiserri reviews significant articles on prevention, public health, and policy advances in viral hepatitis. This month, he highlights “Dismantling Barriers to Hepatitis B and Delta Screening, Prevention, and Linkage to Care among the PWUD Community in Philadelphia.” Zovich B, Freeland C, Moore H, Sapp K, Qureshi A, Holbert R et al. Viruses 2024; April 18; 16 (4), 628. PMID 38675969
What question(s) does this study address?
Blood borne infections are found at higher rates among persons who inject drugs (PWID) because of the scarcity of harm reduction services that can provide users with access to sterile injection equipment. Of the three most common blood borne viruses that occur at increased frequency among PWID (i.e., HCV, HIV, and HBV) only one is currently preventable through vaccination: the hepatitis B virus.
In general, rates of hepatitis B vaccine coverage among adults are low in the United States. Data from the 2021 National Health Interview Survey (NHIS) showed that well less than half (34.2%) of adults aged 19 years and older had ever received at least one dose of hepatitis B vaccine. Although PWID are at increased risk for hepatitis B infection as a result of their drug using practices, a variety of barriers—including insufficient resources and inadequate staffing –often preclude the provision of HBV vaccination at harm reduction sites and other venues that serve PWID.
Another important reason to provide HBV vaccination is to prevent the future acquisition of hepatitis D. Because HDV (also known as hepatitis delta) is an “incomplete” virus, it requires the presence of HBV to infect human cells. Therefore, people can acquire HDV at the same time they acquire hepatitis B virus infection or as a superinfection if they already have chronic HBV infection. In fact, persons infected with both HDV and HBV progress more rapidly to cirrhosis, liver cancer, and liver disease-related death than those with chronic hepatitis B infection alone (ibid.) And while there are drugs available to treat HBV infection, there are currently no treatments approved by the Food and Drug Administration (FDA) for HDV infection.
In this study Zovich and her colleagues aimed to a) determine the prevalence of HBV and HDV infection among persons seeking services at a harm reduction organization in Philadelphia and b) identify those who are susceptible to HBV infection (meaning that they are also susceptible to HDV infection) and facilitate their linkage to HBV vaccination.
What are the major findings of this report/article?
- Between August and September 2023, 498 persons recruited from a Philadelphia harm reduction organization participated in this study. All participants were tested for hepatitis B surface antigen (HBsAg), hepatitis B surface antibody (HBsAb), and hepatitis B core antibody (HBcAb).
- The study population was 61.4% male, 55% white, 23.9% Black, 11% Hispanic, and 6% multiracial. Participants’ ages ranged from 19 to 76 years with the median age being 40 years.
- 126 participants (25.3%) did not have immunity to hepatitis B virus. 52.6% of the sample (n = 262) had been previously vaccinated and 17.9% (89 participants) were immune due to previous infection. 10 participants (2%) were found to have current HBV infection and 11 participants had isolated HBcAb (which may represent resolved infection with waning immunity, continuing infection with low-level viral replication, or a false-positive test result) and required repeat testing.
- Reflex testing for hepatitis delta antibody was performed on all participants who were positive for HBsAg or were found to have isolated HBcAb. One participant was found to have HDV antibody, representing 10% of those testing positive for HBsAg.
- In general, HBV vaccine-derived immunity was more prevalent among participants who were born after 1991, when HBV vaccine was first recommended for all newborns in the U.S.
What are the implications for the prevention and control of viral hepatitis?
- Despite the availability of effective vaccines to prevent HBV infection, one quarter of study participants—all at high risk due to drug use—were found to be susceptible to infection. Participants without immunity to HBV were encouraged to return to the site on specific dates when the city health department would be providing HBV vaccines free of charge.
- Nearly 20% of participants (99 of 498) in this study had serologic evidence of past or present HBV infection. This rate is nearly five times higher than the 4.3% prevalence of past or present HBV infection documented using 2015—2018 data from the National Health and Nutrition Examination Survey (NHANES).
- The HBV/HDV coinfection rate of 10% found in this study is double the rate of 4.6% found among individuals with HBV who were identified within the All-Payer Claims Database (which represents about 80% of the U.S. population with health insurance).
- Individuals received financial compensation for participating in this study. Addition financial compensation was provided to incentivize return for the in-person review of test results, which proved very effective; only 11% of persons failed to return to learn their HBV test results.
- Sites providing harm reduction services to persons who use drugs (PWUD) are strategic locations for offering viral hepatitis screening, immunization, and linkage to care. But to be effective, service models must be low-threshold and tailored to the needs and preferences of PWUD, for example, offering the first dose of HBV vaccine to susceptible individuals on site and free of charge at the time they learn their test results.
