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News
Despite decades of available vaccines, fewer than 4 in 10 US adults are immune to hepatitis A and fewer than 3 in 10 to hepatitis B — and high-risk groups are faring even worse. A large cross-sectional study found that roughly two-thirds of US adults fall into at least one high-risk category, yet immunity rates remain dangerously low. Clinicians are urged not to assume patients are protected just because vaccines exist.
Despite decades of vaccine availability, a new study published in JAMA Internal Medicine reveals that serologic immunity to hepatitis A virus (HAV) and hepatitis B virus (HBV) remains alarmingly low among US adults. Using National Health and Nutrition Examination Survey (NHANES) data from over 13,500 adults — representing roughly 226 million people nationwide — researchers found that only 39.5% had HAV immunity and just 27.1% had HBV immunity, with vaccine-derived HBV immunity at 25.2%.
What's especially concerning: about two-thirds of US adults belong to at least one high-risk group (including those with chronic liver disease, diabetes, chronic kidney disease, or who are pregnant or immunosuppressed), yet immunity in most of these groups was even lower than in the general population. Notably, patients with advanced chronic kidney disease and pregnant individuals showed comparatively higher immunity — likely due to more structured healthcare access and vaccination protocols.
By the Numbers:
Why it matters: With recent policy shifts — including a December 2025 move to shared clinical decision-making for low-risk infants on HBV vaccination — achieving population-level protection is becoming harder, not easier. Experts are calling for EHR reminders, standing vaccination orders, and better linkage with state vaccine registries to close these dangerous immunity gaps.
