A Different Booster: HBV Vaccines among PLWHA

Because of the shared transmission vectors between HIV and Hepatitis B (HBV), the rate of co-infection is about 10% in the United States, according to the Centers for Disease Control and Prevention (CDC). As a result, people living with HIV (PLWHA) are more likely to experience adverse health impacts including cirrhosis and certain types of liver cancers. A small study conducted in Chile took a look at the recommended HBV vaccine schedule among adults living with HIV and HBV antibody uptake and potentially finding cause for a “high dose” fourth shot to be added into the series for PLWHA.

A giant asterisk belongs on the study’s findings, labeled “deserves further study consideration”. Despite being double-blinded, the study’s greatest weakness included participant pool size (right around 100 participants) and clinical selection criteria (which remains an issue in clinical trial work, generally speaking). In order to be considered for the study, participants generally had to present with an undetectable HIV viral load and no other comorbidities, ruling out application of the resulting data to most PLWHA and especially most long-term survivors or people experiencing barriers to care or medication adherence concerns – or those most likely to be impacted by HIV and HBV co-infection.

The study sought to examine the need for revaccination among PLWHA. Of note, the CDC’s “Pink Book” on HBV does not recommend “boosters” unless a particular “low” threshold of HBV antibodies is met, nor does the publication recommend for routinized serological testing among people who have previously received a vaccine. Therein lies a program and policy problem. We’ll get to that in a moment.

As a result of selection bias favoring those with more ideal circumstances, few participants dropped out of the trial. The study itself found that a fourth and “stronger” dose of vaccine improved antibody responses among people with “well controlled” HIV with an improved HBV antibody response from 50.9% in the low-dose arm of the study to 72% among the high-dose arm of the trial. After a one-year follow up, 80% of participants of the high-dose arm still had sufficient antibody titers, whereas only 39% of the standard-dose arm still had sufficient antibodies for protection.

While Ryan White and CDC funded clinical care programs for PLWHA require HBV monitoring and vaccination efforts as part of their grant funding, few entities necessarily do and almost no private providers do. Federally-funded providers may screen upon intake or initial labs but maintenance screening is not a priority in terms of clinical data collected on a given patient. Even on-site audits from these funders can sometimes look like reviewing particular case files and discussing details but the HBV conversation is not pressing. Rather, a review of intake data can suffice depending on the clinical auditor/consultant (site-visits and audits are often conducted under the supervision of the funding agency but only actually audited by consultants, including staff from other funded clinics).

Public funders aiming to end HBV and the unjust circumstances in which PLWHA are not educated by their providers on the other risks to their health should shift some focus to emphasize the need for preventative care – especially vaccines. Provider education for these publicly funded clinics should include the need to routinize HBV antibody monitoring not just as a concern on behavioral risk factors continuing in a client’s life but because HBV immunity is clearly not necessarily a given, regardless of prior vaccination history.

While the study suggests the need for investigating further, with regard to efficacy of HBV vaccines among PLWHA, the larger question - given the nation-wide rush for another vaccine (and boosters) - creating more robust standards of care among a population known to have immunological “memory-loss” due to the particular cells “attacked” by HIV seems to be in order. Part and parcel to that is tying this level of necessary education to funding and licensure could improve the quality of care PLWHA receive, especially those of low-income and otherwise marginalized identities.