Vaccines

Understanding the Disease

Hepatitis B virus (HBV) is transmitted from one person to another through blood and body fluids, and primarily infects the liver. In the United States, it is most commonly spread through sexual contact or injection drug use. Health care workers and others exposed to infected blood or body fluids are also at high risk for infection. Worldwide, it is most commonly spread to infants by their infected mothers.

Approximately 30% of those who become infected with HBV have no known risk factors.

More than half of those infected with the disease show no signs or symptoms, although they may become chronic carriers of the disease and may develop liver disease or liver cancer later in life (usually by age 40). Symptoms of HBV infection vary and may include loss of appetite, fatigue, nausea, and jaundice (yellow eyes and skin), joint pain, and skin rashes.

Worldwide, over 350 million people have chronic HBV infection, and approximately 1 million HBV patients die annually. An estimated 1.25 million people in the U.S. have chronic HBV infection. Each year, approximately 4,000 to 5,000 children are infected with HBV in the United States. The younger the patient is when the disease is acquired, the more likely it is that he or she will develop chronic liver disease or liver cancer.

Approximately 90% of infants who are infected from their mothers at birth, and between 30 and 50% of those infected before age five, become chronic HBV carriers, while people who are newly infected as adults have only a 6 to 10% risk of chronic infection. For these reasons, hepatitis B immunizations are recommended for routine administration at birth. There are specific protocols to identify infected expectant mothers, for managing children born to infected mothers, and to manage children born to mothers with unknown HBV infection status.

Available Vaccines

The hepatitis B vaccine is available as:

• HBV Recombinant (alone)
• HBV in combination with Haemophilus influenzae type b (Hib) vaccine
• HBV in combination with DTaP (Diphtheria-Tetanus-acellular Pertussis) and inactivated polio vaccines
• HBV in combination with hepatitis A (HAV) vaccine

Product: Engerix-B® (HBV-Recombinant)
Manufacturer: GlaxoSmithKline
Year licensed: 1989

Product: Recombivax HB® (HBV-Recombinant)
Manufacturer: Merck
Year licensed: 1986

Product: Comvax® (HBV and Hib conjugate vaccine)
Manufacturer: Merck
Year licensed: 1996

Product: Twinrix® (HAV and HBV combination vaccine)
Manufacturer: GlaxoSmithKline
Year licensed: 2001

Product Name: Pediarix^TM (HBV, DTaP, and inactivated polio vaccines)
Manufacturer: GlaxoSmithKline
Year licensed: 2002

None of these formulations contain thimerosal preservative. For information on the thimerosal content in these vaccines, see:

• the Food and Drug Administration, or
• Johns Hopkins University’s Institute for Vaccine Safety at www.vaccinesafety.edu/thi-table.htm

History of the Vaccine

The current form of the hepatitis B vaccine has been used in the United States since 1986. To make the vaccine, researchers copy the genetic sequence of a protein contained in the virus into a yeast cell, which is then cultured, purified, and prepared into a vaccine. These recombinant vaccines are safe, induce an immune response, and are incapable of infecting recipients with the hepatitis B virus.

Prior to 1991, the vaccine was recommended only for people who were identified to be at a high risk for acquiring the infection.

In 1991, the recommendation was extended to include all infants as well. This new recommendation was made for several reasons, including:

• Approximately 30% of people who get hepatitis B do not have any identified risk factors, so people at high risk often were not immunized.
• When infants and children are infected with hepatitis B, the odds that they will develop chronic liver disease or cancer are at least three times higher than those infected as adults. Therefore, preventing infection in infants and children is very important.

In 2005, a comprehensive strategy to eliminate HBV transmission in the US was published. This includes the recommendation for

• Routine infant hepatitis B vaccination beginning at birth, before hospital discharge (except in rare cases).
• Enhanced programs for prevention of perinatal HBV infection.
• Routine immunization of all previously unvaccinated children and adolescents.
• Identification and vaccination of previously unvaccinated adults at increased risk for infection.
• In settings where a high proportion of adults are likely to have a risk factor, all unvaccinated adults should receive hepatitis B immunization.

Who Should and Should Not Receive the Vaccine

Who should receive the vaccine?

• Newborns should receive their first dose of vaccine at birth prior to discharge from the newborn nursery.
• Everyone 18 years and younger should receive the HBV vaccine.
• Adults over 18 who are at risk for hepatitis B should receive the HBV vaccine. Adults are at risk for hepatitis B virus infection if they have had more than one sex partner during a six month period; have been evaluated for a sexually transmitted disease; are health care personnel, or are otherwise exposed to infected blood or body fluids; are men who have sex with other men; or use injection drugs.
• People aged 18 and older who are at risk for both HAV and HBV may receive the hepatitis A and B combination vaccine. Adults are at risk for hepatitis A if they are poor; are of certain ethnicities, especially Native Americans, Alaskan Natives, and Mexican Americans; travel to or work where HAV is common; are men who have sex with men; use illicit drugs; work with HAV-infected primates, or HAV virus itself in a laboratory; receive clotting factor concentrates; are infected with other hepatitis viruses; have chronic liver disease and are not already immune to HAV; or have received, or are waiting to receive, a liver transplant.

Who should not receive the vaccine?

• Those who have had a serious allergic reaction to a previous dose of the vaccine should not receive additional doses.
• People who are moderately or severely ill should consult with their physician before receiving any vaccine.

This vaccine is recommended by:

• Advisory Committee on Immunization Practices of the Centers for Disease Control and Prevention
• American Academy of Pediatrics
• American Academy of Family Physicians
• American Thoracic Society

The complete childhood immunization schedule can be found at the CDC Web site.

The summary of adolescent/adult immunization recommendations can be found at the CDC Web site.

Dose Schedule

Most people should get three doses of the hepatitis B vaccine. All newborns should receive a dose of hepatitis B vaccine at birth. For children between the ages of six weeks and seven years, HBV in combination with the DTaP and inactivated polio vaccines (Pediarix^TM1, GlaxoSmithKline) may be given. Or, HBV and Hib conjugate vaccine (Comvax®, Merck) may be given to children between 6 weeks and 15 months. Dialysis patients and immunocompromised people may require additional doses

Receiving combination vaccines from different manufacturers, which may include different component vaccines, can make the dose schedule more complex. However, since giving combination vaccines means fewer shots overall for a child, healthcare providers will usually choose to administer them. Healthcare professionals should attempt to select vaccines for their patients, especially children who have been seen by other practices, based on what they have already been given.

First Dose:

• All newborns should receive a dose of hepatitis B vaccine (not a combination vaccine).
• An infant whose mother is infected with the virus should receive the vaccine (and hepatitis B immune globulin) within 12 hours of birth.
• Older children, adolescents, or adults can receive the hepatitis B vaccine (not hepatitis B vaccine combined with other vaccines) at any time, although it is preferable to give the vaccine by 11 to 12 years of age to previously unimmunized children.

Second Dose:

• Child of an infected mother: between one and two months of age (at least one month after the first dose)
• Child of an uninfected mother: between one and four months of age (at least one month after the first dose)
• Older child, adolescent or adult: one to two months after first dose

Third Dose:

• Child of an infected mother: at six months of age (at least two months after the second dose, and at least four months after the first dose)
• Child of an uninfected mother: between 6 and 18 months of age
• Older child, adolescent, or adult: four to six months after first dose

The hepatitis A and B combination vaccine (Twinrix®, GlaxoSmithKline) is approved for people 18 years and older, and is given on a 0-, 1-, and 6-month schedule.

• 1. NNii uses vaccine trade names only for clarity in our presentation of immunization recommendations. NNii does not recommend specific vaccine brands over others.

Effectiveness of the Vaccine

The series of immunizations with recombinant hepatitis B vaccines are 95% effective at inducing sero-immunity. Because the vaccine has only been in use 20 years, that is how long immunity is known to last. Immunity is probably lifelong.

Known Side Effects

The majority of people who receive the hepatitis B vaccine (65%) do not experience any reactions to it.

About 3% of those immunized will develop pain and tenderness where the shot was given; low-grade fever occurs in about 1% to 6% of vaccine recipients.

Serious reactions are extremely rare. In far less than 1 out of 10,000 shots given, or about .001%, serious allergic reactions including anaphylaxis (a rapid life-threatening allergic response affecting more than one part of the body; it can also be a systemic, whole-body response that causes the airway to swell, close off, and prevent the intake of oxygen) may occur.

Related Issues

The hepatitis A and B combination vaccine has been shown to be as safe and effective as HAV and HBV vaccines given separately.

Allegations that the hepatitis B vaccine causes multiple sclerosis have been made. All scientific research conducted to date disproves this claim. For more information refer to:

• Institute of Medicine. (2002). Immunization Safety Review: Hepatitis B Vaccine and Demyelinating Neurological Disorders. Washington, DC: National Academy Press.
• National Multiple Sclerosis Society. (2001, February). Reports indicate no association between vaccines and MS [Research Report]. New York: Author.

Key References and Sources of Additional Information

• Centers for Disease Control and Prevention (CDC). A comprehensive Immunization strategy to eliminate transmission of hepatitis B virus infection in the United States: Recommendations of the Advisory Committee on Immunization Practices (ACIP). Part 1: Immunization of infants, children and adolescents. Morbidity and Mortality Weekly Reports 54 (RR-16); 1-32.
• American Academy of Pediatrics, Committee on Infectious Diseases. (2003). Hepatitis B. In LK Pickering (Ed.), Red Book: Report of the Committee on Infectious Diseases (26th ed., pp. 318-336). Elk Grove Village, IL: Author.
• Centers for Disease Control and Prevention (CDC). (2000). Hepatitis B vaccine: What you need to know [Vaccine Information Statement (VIS)].
• CDC. (2006). Viral hepatitis B [Online fact sheet].

CDC Information

http://www.cdc.gov/nip/publications/VIS/vis-hep-b.pdf