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Hepatitis B: The Vaccine
Is the vaccine safe and effective?
Over 1 billion doses of the Hepatitis B vaccine have already been administered since the vaccine was invented in 1982. The vaccine is very safe for both children and adults.
Furthermore, the WHO states “studies have shown that the vaccine is 95% effective in preventing children and adults from developing chronic infection if they have not yet been infected.”
Who should be vaccinated?
- Infants within 24 hours of birth
- Children and adolescents between ages 0-18
- Anybody (including adults) whose jobs or activities have a high risk of contact with HBV. It is important to avoid occupational blood exposures.
How does the vaccine work?
To provide maximum protection, the vaccine is given as a series of three doses over a period of four to six months. For children and adolescents, a monovalent HBV vaccine is manufactured by major pharmaceutical companies: Recombivax by Merck and Engerix-B by GlaxoSmithKline. Both of these can be used concurrently with hepatitis B immune globulin (HBIG), which is made from blood plasma and can prevent hepatitis B within 14 days of exposure to the virus.
Why should infants be vaccinated immediately following birth?
The CDC says perinatal transmission of HBV can be effectively prevented if the child of an HBV-positive mother immediately receives immunoprophylaxis, the prevention of disease by producing immunity in the body. This is done through vaccination. Doing this is crucial for infants born to uninfected mothers as well since newborns are most susceptible to hepatitis B infections in the first year of life. The earlier the shot is administered, the greater the possibility that their bodies can repel HBV attacks.
What is the vaccination schedule for newborn infants?
| Table 1: Hepatitis B vaccine schedules for newborn infants, by maternal hepatitis B surface antigen (HBsAg) status |
| Maternal HBsAg status |
Single-antigen vaccine
|
| |
Dose
|
Age
|
Positive
|
1
|
Birth (<12 hrs)
|
| |
HBIG
|
Birth (<12 hrs)
|
| |
2
|
1-2 mos
|
| |
3
|
6 mos
|
| |
|
|
Unknown
|
1
|
Birth (<12 hrs)
|
| |
2
|
1-2 mos
|
| |
3
|
6 mos
|
| |
|
|
Negative
|
1
|
Birth (before hospital discharge)
|
| |
2
|
1-2 mos
|
| |
3
|
6-18 mos
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What is a catch-up vaccination schedule?
The U.S. Centers for Disease Control and Prevention provides a catch-up immunization schedule for persons between 24 months and 18 years of age who start late: the second dose can be given a minimum of 4 weeks after the first, and the third can be given 8 weeks after the second dose but no less than 16 weeks after the first.
Should the vaccination series be restarted if there are interruptions between doses?
No. The second dose must be administered as soon as possible if only the first dose is interrupted. If the first two shots have already been given, the third dose may be administered at any time.
Does the Hepatitis B vaccine work for people who have already been infected?
The vaccine has not been shown to be effective for infected patients. However, it is also not harmful.
Because infection does not immediately set in, it can be prevented if appropriate action is taken within a certain time window after exposure to the virus. Regimens involving hepatitis B vaccine alone or hepatitis B immune globulin (HBIG) alone have a success rate of 70-75%. A combination immunization program is more effective in some circumstances.
What is the Hepatitis B Immune Globulin (HBIG)?
HBIG is administered to prevent development of an HBV infection within 14 days of exposure to the virus. It provides short-term protection for 3-6 months. HBIG is prepared from blood plasma containing high concentrations of anti-HBs.
How long can the Hepatitis B vaccine last for?
Immunity is estimated to be life-long. Since the vaccine first came out in 1982, we know it definitely provides protection for at least 23 years. Immune memory is indefinite. At this point, routine booster doses are not recommended.
Is post-vaccination testing necessary?
High-risk people such as health care personnel and immune-compromised patients should receive post-vaccination testing (the anti-HBs test) to confirm the presence of anti-HBs in concentrations greater than 10mlU/mL. If antibody levels are not detectable, repeat the 3-dose series according to the recommended schedule. 50% of vaccine non-responders will develop protective levels after repeating the immunization program. Over six doses of vaccine should not be administered. |
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