The hepatitis B vaccine is an active immunization agent used to prevent hepatitis B virus infection. Its primary purpose is to stimulate the human immune system to produce antibodies, enabling vaccine recipients to effectively block infection upon exposure to the virus. This vaccine is suitable for all age groups, especially high-risk populations (such as healthcare workers, household contacts, and patients with chronic illnesses) to provide long-term protection.
The development of the hepatitis B vaccine is based on the hepatitis B surface antigen (HBsAg), which effectively induces T-cell and B-cell responses, forming immunological memory. The World Health Organization (WHO) recommends integrating it into childhood immunization programs to prevent vertical transmission and community spread of the virus.
This vaccine is a recombinant DNA vaccine produced using genetic engineering techniques to generate the viral surface antigen protein, which does not contain live virus or viral nucleic acids, thus posing no pathogenic risk. After vaccination, the antigen components are captured by antigen-presenting cells, further activating helper T cells and B cells, leading to the production of anti-HBs antibodies and the formation of active immune memory.
The vaccine is typically administered via intramuscular injection. About 90% of healthy adults will develop sufficient antibody titers within 6 months post-vaccination. The immune response can last for decades, with some studies indicating protection lasting over 20 years.
Primarily for individuals of all ages who are uninfected and lack antibodies, including:
Additionally, the vaccine is used for emergency prophylaxis after accidental blood exposure, usually in conjunction with immunoglobulin. Candidates should be screened to exclude those with existing chronic hepatitis B or acute infection.
The standard vaccination schedule involves three doses, with dosages adjusted according to age and weight:
The injection site is usually the deltoid muscle of the upper arm; for children, the anterior thigh may be chosen. After completing the primary series, it is recommended to test antibody titers 1-2 months after the last dose to confirm immune response.
Main benefits include:
Compared to immunoglobulin, the vaccine provides long-lasting active immunity, whereas immunoglobulin offers only short-term passive protection. The antibody persistence post-vaccination surpasses that of other similar viruses, such as the human papillomavirus (HPV) vaccine.
Common local reactions include pain, redness, or induration at the injection site, occurring in about 25-30% of recipients, usually resolving within 2-3 days. Systemic reactions such as fever and fatigue occur in approximately 5-10% of cases, generally mild in severity.
Serious allergic reactions are extremely rare, with an incidence of less than 1 in 1,000,000: symptoms may include difficulty breathing, hives, or hypotension. Those with known allergies to yeast or other vaccine components should avoid vaccination.
Contraindications include:
Pregnant or breastfeeding women can safely receive the vaccine, as its components do not affect the fetus or infant. Prior to vaccination, individuals should inform their healthcare provider of any allergies or current health conditions to assess suitability.
Currently, no known direct interactions with other vaccines exist, but it is recommended to space at least 4 weeks between vaccinations. Concurrent use with immunosuppressants (such as corticosteroids) may reduce antibody response and should be managed under medical supervision.
When administered with tetanus or pertussis vaccines, it is advisable to inject at separate sites to facilitate reaction monitoring. Patients should inform their healthcare provider of any medications they are using, especially those affecting the immune system.
Third-generation vaccines have a protection rate of up to 95%, with neonatal vaccination reducing chronic infection rates from 90% to nearly zero. Global health statistics show that in countries with high vaccination coverage, hepatitis B prevalence has decreased by over 70%.
Long-term follow-up studies indicate that individuals with antibody levels below 10 mIU/mL can regain protection after booster doses, with over 90% responding positively. The vaccine is effective against all genotypes of hepatitis B virus, including the predominant Asian strains B and C.
Currently, no other vaccines can fully replace the hepatitis B vaccine. However, in cases of emergency exposure, hepatitis B immunoglobulin can be used to provide immediate passive immunity, ideally administered concurrently with the vaccine for optimal protection.
If unvaccinated individuals are infected, antiviral treatment (such as entecavir) may be necessary, but such therapy requires lifelong administration and cannot eradicate the virus, making vaccination the preferred preventive measure.
Is it normal to experience redness, swelling, or fever at the injection site after vaccination? How should it be handled?
Local redness or mild fever (below 38°C) after vaccination are common reactions and usually resolve within 2-3 days. Applying cold compresses can help reduce redness and swelling. Avoid scratching the injection site; if the temperature exceeds 38.5°C or symptoms persist beyond 48 hours, seek medical evaluation for further management.
If I still get hepatitis B infection after vaccination, does it mean the vaccine is ineffective?
The vaccine offers over 90% protection, but a very small number of individuals may have an inadequate immune response due to personal differences. If infection occurs post-vaccination, blood tests should be conducted to determine whether the vaccination schedule was completed, timing was sufficient, or if immune deficiency is involved. In such cases, the healthcare provider may adjust the vaccination strategy or monitor antibody levels.
Are there any dietary restrictions or activities to avoid during hepatitis B vaccination?
No specific dietary restrictions are necessary post-vaccination, but it is advisable to avoid excessive alcohol intake, as alcohol can impair immune response. Strenuous exercise should be avoided on the day of vaccination to reduce injection site discomfort, but normal daily activities (such as walking or light work) are generally unaffected.
How long after completing hepatitis B vaccination should I have an antibody test?
It is recommended to perform an anti-HBs antibody test 1-2 months after completing the full vaccination series to confirm adequate protection (antibody concentration ≥10 mIU/mL). If antibody levels are insufficient, the healthcare provider may suggest additional doses or booster immunizations to ensure long-term protection.
How long does the protection from hepatitis B vaccination last? Is booster vaccination necessary?
The antibodies generated by the vaccine usually last over 10 years, but protection duration varies among individuals. High-risk groups (such as healthcare workers and household contacts) are advised to check antibody levels every 5 years. Generally, if antibody testing shows adequate protection, immediate revaccination is not required. Immunocompromised individuals may need more frequent monitoring and booster doses.
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