“My wife and I are both hepatitis B carriers—can we have children?” “I’ve received two vaccine doses; what should I do if I’ve forgotten to get the third?”

“I got the hepatitis B vaccine, but tests show I have no antibodies. Could there be something wrong with the vaccine I received?”

“400 Jun,” who is on the front lines handling calls on the consultation hotline, frequently receives the aforementioned inquiries phrased with a tone of “anxiety.”

To address everyone’s concerns, Editor 400 has summarized information on hepatitis B. “10 Questions” , it summarizes and provides detailed solutions to the “accidents” that people most frequently encounter.

Q: If a child does not test positive for antibodies after receiving the hepatitis B vaccine, does this mean she/he has no immunity to the hepatitis B virus?

A: No vaccine can guarantee 100% efficacy. Due to vaccine-related factors or individual differences, some children may fail to develop detectable antibodies after receiving the hepatitis B vaccine.

Currently, the assays for detecting hepatitis B surface antibodies have relatively low sensitivity, so protective antibodies may already be present in the body yet remain undetectable. Furthermore, after the hepatitis B vaccine is administered, immunity is generated through two distinct immune pathways: first, humoral immunity produces protective antibodies; second, cellular immunity—mediated by macrophages, NK cells, and other effector cells—eliminates the hepatitis B virus. In other words, even in the absence of detectable antibodies, cellular immunity can still confer protection against the virus.

Moreover, even in the absence of antibody production, one can still benefit from “herd immunity.” Imagine that everyone around you has been vaccinated and is resistant to the hepatitis B virus—this creates an immune barrier, and those within it are naturally protected as well.

Q: How effective is the hepatitis B vaccine?

A: The hepatitis B vaccine is an effective, cost‑efficient, and safe measure for preventing hepatitis B.

Since 1982, thanks to the widespread use of the hepatitis B vaccine, by 2015 the global prevalence of chronic hepatitis B virus infection among children under five years of age had declined to an estimated level of 1.3% .[1]

In May 2012, China achieved the World Health Organization’s target of reducing the prevalence of hepatitis B surface antigen carriage among children under five years of age to Below 2% ”, and in 2017, it had already achieved the target of keeping it within Less than 1% The goal.

According to estimates, since 1992, at least… nationwide has been… 80 million people Being protected from hepatitis B virus infection has, at a minimum, safeguarded 19 million people Avoid becoming a carrier of the hepatitis B virus surface antigen. [2]

Q: Why is the antibody test still negative after receiving the hepatitis B vaccine?

A: We refer to the phenomenon of undetectable surface antibodies after hepatitis B vaccination as non‑response. Why do some individuals fail to mount a response? The underlying mechanisms are not yet fully elucidated, but the following major factors have been clearly identified:

(1) Heredity

Research has found that antibody production following hepatitis B vaccination is associated with human leukocyte antigen (HLA) types; HLA-DR7, HLA-DR3, and T‑cell deficiencies may all lead to non‑response or a low response after vaccination.

(2) Immunity

Some studies have shown that a reduction in the number and impaired function of certain immune cells can also affect antibody production, leading to an inadequate immune response.

(3) Hepatitis B virus mutation

The hepatitis B virus is prone to mutation, and these mutations can alter its biological characteristics. If the vaccine fails to effectively recognize the mutated virus, it will lose its efficacy.

(4) Already infected with the hepatitis B virus

If a person is already infected with a small amount of hepatitis B virus prior to vaccination, existing diagnostic methods may fail to detect surface antibodies. In such cases, the body remains in an immune-tolerant state and cannot mount a normal immune response to the hepatitis B vaccine.

(5) The detection method lacks sensitivity.

At present, the “hepatitis B surface antigen and antibody” assay used in the “two‑and‑a‑half” test has relatively low sensitivity. As a result, even if protective antibodies have already developed in the body, they may go undetected, leading to the erroneous conclusion that no antibodies are present.

(6) Other

Age, sex, body weight, smoking status, alcohol consumption, vaccine type, injection site, dose, interval between doses, and maternal serum viral load are all associated with non-response. Furthermore, conditions such as malnutrition, HIV infection, organ transplantation, and hemodialysis that impair immune function can also lead to non-response.

Q: I’m a pregnant woman in my seventh month, and both my husband and I are hepatitis B carriers. In this situation, how should we prevent hepatitis B transmission after the baby is born?

A: To maximize protection for newborns, hepatitis B vaccination and a 100 IU dose of hepatitis B immune globulin should be administered as soon as possible within 24 hours after birth, followed by completion of the full hepatitis B vaccination series at 1 month and 6 months of age.

Q: During the primary vaccination series with the hepatitis B vaccine, if the manufacturers or vaccine types of the three doses differ, what issues might arise? Is the vaccination still effective?

A: Switching between different manufacturers, vaccine types, or doses generally does not affect efficacy. However, it is preferable to use hepatitis B vaccines from the same brand and in the same formulation.

Q: After a newborn has completed the full three-dose hepatitis B vaccination series, when can antibody levels be tested?

A: After completing the full three-dose hepatitis B vaccination series, routine antibody (anti‑HBs) testing is generally not required for the general population. However, if the mother is HBsAg‑positive, antibody testing is recommended for the newborn; blood can be drawn one month after completion of the full vaccination course. If anti‑HBs levels are < 10 mIU/mL, a booster dose should be administered.

Q: Can the hepatitis B vaccine be administered simultaneously with other vaccines?

A: According to the “National Immunization Program Vaccination Schedule and Instructions for Children (2016 Edition),” all vaccines included in the National Immunization Program—including the hepatitis B vaccine—may be administered simultaneously. When the hepatitis B vaccine is given concurrently with other vaccines, it should be injected at separate sites.

Q: How long does the protection provided by the hepatitis B vaccine last?

A: The antibody levels induced by hepatitis B vaccination gradually decline over time. Higher antibody titers tend to persist for a longer duration. Typically, after receiving the three-dose vaccine series, peak antibody levels are observed 1–3 months post‑vaccination. 97% All individuals can detect hepatitis B surface antibody (anti‑HBs); at one year, the antibody level remains stable, but the seroconversion rate gradually declines, dropping to approximately 74% by the third year after vaccination, with antibody titers also declining over time. Current extensive data indicate that, following hepatitis B vaccination, the protective efficacy among those who mount an antibody response generally persists for at least… 20 years . [3]

Q: After infection with the hepatitis B virus, what is the likelihood of progressing to chronic hepatitis, cirrhosis, and hepatocellular carcinoma?

A:

★ Within 1 year old Infection, approximately 90% It may progress to chronic infection;

★ 1–4 years old Infection, 20%～50% It may progress to chronic infection;

★ Less than 10% of adults who become infected progress to chronic infection;

★Among patients with chronic HBV infection, there are 15%–25% It may progress to cirrhosis or hepatocellular carcinoma, leading to premature death;

★ Worldwide, approximately 80% Of the hepatocellular carcinoma cases, [2] were attributable to HBV infection.

Q: Who is at high risk of contracting the hepatitis B virus?

A: Humans are the only natural host of the hepatitis B virus, and the virus is universally susceptible in the human population. High-risk groups for hepatitis B virus infection can be divided into two categories:

★ Newborns and children without immunity, especially those whose mothers are positive for hepatitis B surface antigen;

★ Other high-risk groups: healthcare workers; individuals who frequently come into contact with blood or bodily fluids; staff at childcare and early‑education facilities; spouses, family members, or close contacts of hepatitis B patients and HBV carriers; organ transplant recipients; persons who regularly receive blood transfusions or blood products; individuals with compromised immune function; those prone to trauma; people with multiple sexual partners or engaged in high‑risk sexual behavior; and intravenous drug users, among others.