Serologic Immunity to Hepatitis A and B Remains Low Among US Adults

Despite the availability of effective vaccines, fewer than half of US adults have serologic evidence of immunity to hepatitis A virus (HAV), and little more than one-quarter have evidence of immunity to hepatitis B virus (HBV), according to a cross-sectional study published in JAMA Internal Medicine.¹

The findings identify persistent opportunities for pharmacists and other clinicians to assess vaccination histories, recommend indicated vaccines, and connect patients with preventive care.

National Analysis Identifies Broad Immunity Gaps

Researchers analyzed National Health and Nutrition Examination Survey data collected from January 2017 through August 2023. The analysis included 13,514 adults aged 20 years or older with available HAV and HBV serologic results, representing approximately 226.1 million US adults after weighting.¹

Overall, 39.5% of adults demonstrated serologic immunity to HAV, corresponding to approximately 89.4 million people. Approximately 27.1%, or 61.3 million adults, had serologic immunity to HBV, while 25.2% had immunity attributed specifically to vaccination.¹

The researchers defined HAV immunity through hepatitis A antibody positivity. HBV immunity was based on hepatitis B surface antibody positivity, with vaccine-derived immunity identified by surface antibody positivity without hepatitis B core antibodies.

Immunity differed across demographic groups. HAV immunity was highest among Asian adults at 79%, Mexican American adults at 75%, and other Hispanic adults at 65%. HBV immunity was highest among Asian adults at 46%, Black adults at 32%, and other Hispanic adults at 27%. Adults born outside the United States had higher HAV and HBV immunity than the overall population, at 77% and 31%, respectively.¹

Older adults demonstrated a particularly pronounced HBV immunity gap. Among individuals aged 65 years or older, approximately 39% had HAV immunity, whereas only 13.5% had serologic HBV immunity.

Low Immunity Persists in High-Risk Populations

Suboptimal immunity was also observed among groups at increased risk of acquiring viral hepatitis or experiencing serious complications. HAV and HBV immunity prevalence was approximately 39% and 22%, respectively, among adults with dysglycemia or diabetes; 36% and 20% among those with immunosuppression; and 38% and 23% among patients with chronic liver disease without advanced fibrosis.¹

Among patients with advanced liver fibrosis, HAV and HBV immunity prevalence was approximately 37% and 18%, respectively. Corresponding estimates were 41% and 14% among adults with chronic kidney disease, 34% and 22% among individuals with significant alcohol use, and 47% and 39% among pregnant individuals.¹

These findings are clinically important because existing CDC recommendations prioritize several of these populations. Hepatitis A vaccination is recommended for unvaccinated adults at increased risk of infection or severe disease, including people with chronic liver disease, HIV, homelessness, or drug use, as well as international travelers and any individual requesting protection.²

Hepatitis B vaccination is recommended routinely for adults aged 19 through 59 years. Adults aged 60 years or older with HBV risk factors should also receive vaccination, and those without identified risk factors may receive it.³

Pharmacists Can Address Missed Vaccination Opportunities

The researchers described the findings as evidence of missed preventive opportunities, noting that many at-risk patients may never receive hepatology-directed services. Pharmacists can help close this gap by incorporating immunization assessment into medication reviews, chronic disease management, hospital discharge services, and encounters involving diabetes, kidney disease, liver disease, or immunosuppressive therapy.

CDC data further indicate that adult HBV vaccination uptake has remained limited. Among adults born before the 1991 universal childhood vaccination recommendation, vaccination coverage was 32.5% in 2023. Fewer than half knew they were eligible, and only 30% reported receiving a vaccination recommendation from a health care professional.⁴

The study may also provide a baseline for evaluating the effects of subsequent vaccine-policy changes. In December 2025, the CDC adopted individual-based decision-making for the HBV birth dose among infants born to mothers who test negative for HBV. Infants born to mothers with positive or unknown HBV status should continue to receive vaccine within 12 hours of birth.⁵

Study limitations included the exclusion of institutionalized populations and people experiencing homelessness, potentially limiting estimates among groups with elevated infection risk. Additionally, hepatitis B surface antibody concentrations can decline over time even when immune memory persists. Consequently, serologic testing may underestimate protection in some previously vaccinated individuals.

These results demonstrate substantial gaps in detectable population-level immunity and reinforce the importance of systematic screening, strong clinician recommendations, and accessible vaccination services.

References

1. Roldan GA, Fletcher J, Davie T, Leventhal TM, Lake JR, Udompap P. Serologic Immunity to Hepatitis A and B in US Adults and High-Risk Populations. JAMA Intern Med. Published online August 17, 2026. doi:10.1001/jamainternmed.2026.3831

2. Centers for Disease Control and Prevention. Hepatitis A vaccine administration. Published January 31, 2025. Accessed August 18th, 2026. https://www.cdc.gov/hepatitis-a/hcp/vaccine-administration/index.html

3. Centers for Disease Control and Prevention. Hepatitis B vaccine. https://www.cdc.gov/hepatitis-b/vaccination/index.html

4. Centers for Disease Control and Prevention. Hepatitis B vaccination coverage among adults in the United States, 2023. PublishedFebruary 26, 2026. Accessed August 18th, 2026. https://www.cdc.gov/adultvaxview/publications-resources/adult-hepb-vaccination-coverage-2023.html

5. Centers for Disease Control and Prevention. CDC adopts individual-based decision-making for hepatitis B immunization. Published December 16, 2025. Accessed August 18th, 2026. https://www.cdc.gov/media/releases/2025/2025-hepatitis-b-immunization.html