Immunization

• All major authorities, including Advisory Committee on Immunization Practices, American Academy of Family Physicians (AAFP), American College of Obstetricians and Gynecologists, American College of Physicians, and US Preventive Services Task Force (USPSTF) --
• Individuals in groups at increased risk for HBV infection ( see Table 48.1) should be vaccinated with the hepatitis B vaccine. The USPSTF has also recommended routine immunization of all young adults not previously immunized. The AAFP recommends offering immunization to young adults to age 24 years who have no reliable history of HBV infection or previous immunization.

Prophylaxis

• All major authorities, including Advisory Committee on Immunization Practices, American College of Physicians (ACP), Canadian Task Force on the Periodic Health Examination, and US Preventive Services Task Force --
• HBIG should be used for prophylaxis of unimmunized or inadequately immunized adults exposed to percutaneous or mucosal contact with hepatitis B surface antigen (HBsAg)-positive blood or sexual contact with a person with acute HBV infection. ACP has also recommended HBIG use after sexual contact with an asymptomatic person who is HBsAg-positive.

1. Vaccine Types

Two types of recombinant-derived hepatitis B vaccines are currently licensed for use in the United States -- Recombivax HB® and Engerix-B®. These vaccines may be used interchangeably at any point in the vaccination schedule. Plasma-derived vaccine is no longer distributed in the United States.

2. Schedule

Both vaccines are given as a three-dose series, with the second and third doses administered 1 and 6 months after the first dose. If a three-dose series is interrupted after the first dose, administer the second dose as soon as possible. Separate administration of the second and third doses by at least 2 months. A four-dose series (at 0, 1, 2, and 12 months), which may induce immunity faster than a three-dose series, has been approved for Engerix-B ® vaccine but has not been shown to be advantageous in clinical trials. Upon completion, both the three- and four-dose regimens confer essentially the same level of immunity. For hemodialysis patients, the fourth dose of Engerix-B ® vaccine should be given 6 months (rather than 12 months) after the first dose. Patients in whom postvaccination testing shows inadequate antibody response after the initial vaccination series may receive one or more additional doses of vaccine.

3. Assessing Immunity

In adult populations at high risk for HBV infection, prevaccination antibody testing with hepatitis B core antibody (anti-HBc) and hepatitis B surface antibody (anti-HBs) may be cost-effective. The decision to undertake prevaccination testing should take into account the cost of vaccination, the cost of testing for susceptibility, and the expected number of immune individuals. Also consider the likelihood of patient follow-up and vaccine delivery after prevaccination testing.

Postvaccination testing is indicated for immunocompromised persons who are at continued risk of HBV infection (eg, dialysis patients), because their future medical management may depend on knowledge of their immune status. Persons at occupational risk with continued percutaneous/mucosal exposures (eg, sharp injuries, blood splashes) should be tested after vaccination, because knowledge of their antibody status is needed to determine proper postexposure prophylaxis. All health care workers who have contact with patients or blood (eg, physicians, nurses, operating room technicians, dentists, dental hygienists, emergency medical technicians, phlebotomists, laboratory technologists/technicians, physician assistants, nurse practitioners) should be tested. Health care personnel who were vaccinated as students should also undergo postvaccination testing. Postvaccination testing is not indicated for persons at low risk of continued mucosal or percutaneous exposures to blood (eg, public safety workers, health care workers without direct patient contact). Consider postvaccination testing of sexual partners of persons with chronic HBV infection. If such contacts are aware of their immune status, those who are vaccine nonresponders can use methods to prevent sexual transmission of HBV infection.

Perform postvaccination antibody testing between 1 and 2 months after completion of the vaccine series. Maximum antibody response occurs at approximately 6 weeks following the third dose of vaccine. Antibody has been shown to disappear within 6 months of vaccination in adults.

4. Dose and Administration

For adults older than 19 years of age, the recommended dose of both types of vaccine is 1 mL given intramuscularly. ( See Table 14.2 for recommended doses of hepatitis B vaccine for individuals 19 years of age and younger.) The proper injection site is the deltoid muscle; injection into the buttock results in decreased antibody response because of deposition of vaccine into fat. Hepatitis B vaccine may be given concurrently with HBIG and other vaccines but at different sites. Increase the dose for hemodialysis patients and those who are immunocompromised. The Advisory Committee on Immunization Practices recommends using either 1 mL of a special formulation of Recombivax HB ® containing 40 μ g or two 1-mL doses of Engerix-B ® given at the same site.

5. Contraindications/Precautions

The only contraindication to hepatitis B vaccination is prior anaphylaxis or severe hypersensitivity to the vaccine or its components. Pregnancy and lactation are not contraindications to vaccination.

6. Adverse Reactions

The side effects of hepatitis B vaccination are relatively minor and include pain at the injection site (3% to 29% of patients) and temperature higher than 37.7 ° C (100 ° F) (1% to 6% of patients). The reported rate of occurrence of Guillain-Barré syndrome is very low (0.5 cases per 100,000 population) among adults receiving plasma-derived HBV vaccine. No such association has been found with the use of recombinant hepatitis vaccines, although insufficient data are available from which to draw firm conclusions on this issue. The estimated incidence of anaphylaxis is low (one case per 600,000 doses distributed). Very rarely hepatitis B vaccine may cause a life-threatening hypersensitivity reaction in certain individuals.

Any adverse side effects should be reported to the Vaccine Adverse Events Reporting System (VAERS). See Table B.4 for a detailed listing of adverse events. VAERS forms and instructions are available in the FDA Drug Bulletin (Food and Drug Administration) and the Physician's Desk Reference or by calling the 24-hour VAERS information recording at (800)822-7967. Refer to Appendix B for details.

7. Patient Education

The US Department of Health and Human Services has developed vaccine information statements about hepatitis B vaccination (see Patient Resources). These statements must be available to patients in facilities where federally purchased vaccines are used, and their availability in other settings is encouraged.

8. Vaccine Storage and Handling

Store vaccine at 2 ° to 8 ° C (36 ° to 46 ° F); freezing the vaccine will destroy its potency. Do not use vaccine that has been frozen. Handle all vaccine preparations according to manufacturers' instructions.

1. Indications

According to the Advisory Committee on Immunization Practices (ACIP), all susceptible sexual partners of persons with acute HBV infection should receive a dose of HBIG if prophylaxis can begin within 14 days of the last sexual exposure; the HBV vaccine series should also be started. HBIG is not recommended for sexual contacts of persons with chronic HBV infection. For postexposure prophylaxis of persons not previously vaccinated, ACIP recommends use of hepatitis B vaccine in addition to HBIG. An alternative treatment for exposed individuals who would not routinely be considered at high risk and in need of vaccination is to administer one dose of HBIG (without vaccine) and retest the sex partner's HBsAg status 3 months later. If the sex partner has become HBsAg-negative, no further treatment is needed. If the sex partner is still HBsAg-positive, a second dose of HBIG should be given and a vaccination series begun. Adult household contacts of individuals with acute HBV infection do not need prophylaxis with HBIG unless they have had identifiable blood exposure, such as that which occurs by sharing a toothbrush or razor with the infected individual. Patients with such exposures should be treated in the same manner as patients with sexual exposure. If the index patient becomes a HBV carrier, all household contacts should receive hepatitis B vaccine. The recommendations of ACIP for HBV prophylaxis following percutaneous or mucosal exposure to blood and for sexual contacts of persons with acute HBV infection are given in Table 48.2.

2. Schedule

Administer HBIG as soon as possible after exposure to infection. HBIG may be given as late as 14 days after exposure, but the effectiveness of HBIG is uncertain if it is given 7 days or more after exposure. If the patient is known to have been nonresponsive to a primary HBV vaccination series (by anti-HBsAg level), give a second injection of HBIG 1 month later in lieu of a vaccine booster dose.

3. Dose and Administration

The recommended dose of HBIG is 0.06 mL/kg given intramuscularly. The preferred site for administration in adults is the deltoid muscle. If the gluteal region is used, administer the vaccine only to the upper, outer quadrant. Before injection, draw back the plunger to verify that injection into a vein or artery will not occur. HBIG and hepatitis B vaccine may be given concurrently but at different sites.

4. Contraindications/Precautions

Use HBIG with caution in patients with a history of hypersensitivity to human immune globulin (IG) preparations or thimerosal.

5. Adverse Reactions

The main side effects of HBIG injection are pain and swelling at the injection site. Urticaria, angioedema, and very rarely, anaphylaxis can occur. HIV is not known to be transmitted by HBIG injection.