Answer:

After hepatitis B vaccination, individuals can still contract the infection, though the rate is low. Vaccine effectiveness depends on factors such as health, age, immune status, and adherence to the vaccination schedule. Some people may still acquire hepatitis B if their body does not produce antibodies (AntiHBs, HBsAb) or produces low levels of antibodies after vaccination.

The risk of hepatitis B infection, even after vaccination, is higher for individuals with weakened immune systems, such as those undergoing cancer treatment, living with HIV/AIDS, or taking immunosuppressants. It is also elevated for people frequently exposed to high viral loads, those who have not completed the full vaccination course, or those who do not receive booster shots when antibody levels decline.

Doctor Mai advises a patient. Illustration: Tam Anh General Hospital

To determine if the body has sufficient immunity, individuals should undergo a blood test to check antibody levels (AntiHBs, HBsAb) approximately one to two months after vaccination. An antibody level of 10 mIU/mL or higher indicates protective antibodies against the hepatitis B virus.

For people living in high-prevalence hepatitis B endemic areas, healthcare workers, those living with hepatitis B virus-infected individuals, or those at risk of blood exposure, an AntiHBs (HBsAb) antibody level exceeding 100 mIU/mL indicates a strong immune response and sufficient protection. If levels are lower, additional booster doses or re-vaccination may be necessary, as advised by a doctor.

While hepatitis B vaccination helps reduce infection risk, you should combine it with other preventive measures to enhance protection. These include avoiding sharing personal items that might come into contact with blood, such as needles, razors, or toothbrushes, and practicing safe sex.

The hepatitis B virus is not transmitted through food or drink, including sharing beverages. To prevent HBV infection, you should proactively get health check-ups and blood tests to check antibody levels for yourself, your children, and family members. This allows for hepatitis B vaccination if antibody levels are insufficient.

Master, Doctor Nguyen Thi Tuyet Mai

Department of Gastroenterology - Hepatobiliary

Tam Anh General Clinic District 7