From the Guidelines
This 18-year-old male requires hepatitis B vaccination due to his inadequate immunity, as indicated by a hepatitis B surface antibody level of 0.36 IU/L, which is below the protective level of ≥10 IU/L 1. Given his history of hepatitis B treatment and current low antibody level, he is at risk of reinfection, which could lead to more severe liver damage.
- His normal liver function tests (AST, ALT, GGT) and inflammatory markers (CRP) do not negate the need for vaccination, as the primary concern is preventing future infection.
- The hepatitis B vaccine is safe and highly effective, with protection rates over 95% in young adults who complete the full series 1.
- He should receive a complete hepatitis B vaccination series consisting of three doses: the initial dose, followed by a second dose 1 month later, and a third dose 6 months after the first.
- After completing the series, antibody levels should be checked 1-2 months later to confirm immunity, as some individuals may not respond to the vaccine and require additional doses or alternative approaches 1.
- It is essential to note that, according to the Advisory Committee on Immunization Practices (ACIP), persons who do not respond to a primary 3-dose vaccine series may respond to an additional vaccine dose or a 3-dose revaccination series, but more than two vaccine series are not recommended in nonresponders 1.
From the FDA Drug Label
Antibody titers ≥10 mIU/mL against HBsAg are recognized as conferring protection against hepatitis B. The patient's hepatitis B surface antibody is 0.36 IU/L, which is below the protective level of ≥10 mIU/mL.
- The patient is not protected against hepatitis B.
- Booster vaccination may be necessary to achieve protective antibody levels 2, 2.
From the Research
Hepatitis B Surface Antibody Levels
- The patient's hepatitis B surface antibody level is 0.36 IU/L, which is considered low 3.
- A study from 1985 found that isolated anti-HBs levels were low and did not persist, and the immunologic specificity and protective value of anti-HBs, especially when levels are low, remain questionable 3.
- Another study from 2014 found that viral clearance can be achieved for high anti-HBV antibody levels, but the mechanism of protection is complex and depends on various factors, including the rate of synthesis of hepatitis B subviral particles and the rate of anti-HBV antibody production 4.
Protective Levels of Hepatitis B Surface Antibody
- A study from 2020 found that the prevalence of protective levels of hepatitis B surface antibody (anti-HBs) among adults at high risk of HBV infection was around 23.4%, and the prevalence increased from 2003-2006 to 2007-2010, but no change occurred from 2007-2010 to 2011-2014 5.
- The same study found that factors associated with positive anti-HBs serology included young age and higher education 5.
- A study from 2023 found that hepatitis B vaccination in patients after HBsAg seroclearance increased the anti-HBs seroconversion rate and significantly increased antibody levels, with good safety 6.
Clinical Significance of Antibody to Hepatitis B Surface Antigen
- A study from 2025 found that anti-HBs is recognized as a protective immune marker, both for HBV infection clearance and following vaccination, and it is also considered an important indicator of functional cure for CHB 7.
- The same study found that the restoration of HBV-specific B cell function, along with the induction of an anti-HBs antibody response, is regarded as pivotal for terminating chronic HBV infection and achieving functional cure 7.