CDC Travelers' Health Information on Hepatitis, Viral, Type B Hepatitis, Viral, Type B Description Hepatitis B is a viral infection with clinical manifestations that include anorexia, abdominal discomfort, nausea, and vomiting, and often progresses to jaundice. Severity ranges from inapparent infections detectable only by elevated liver function tests to fulminating, fatal cases of acute hepatic necrosis. Hepatitis B virus (HBV) is transmitted primarily through activities that involve contact with blood or blood-derived fluids. The most frequent mode of transmission is through sexual activity, either heterosexual or homosexual, between an infected and a susceptible person. Principal activities that can result in blood exposure include working in health care fields (medical, dental, laboratory, or other) that entail direct exposure to human blood; receiving blood transfusions that have not been screened for HBV; and having dental, medical, or other exposure to needles (for example, acupuncture, tattooing, or injecting drug use) that are contaminated with HBV. In addition, open skin lesions in children or adults, due to factors such as impetigo, scabies, and scratched insect bites, can play a role in disease transmission if direct exposure to wound exudates occurs. Occurrence The prevalence of chronic HBV infection is high (>8%) in all socioeconomic groups in certain areas (see Map 3-3): all of Africa; Southeast Asia, including China, Korea, Indonesia, and the Philippines; the Middle East, except Israel; south and western Pacific islands; the interior Amazon River basin; and certain parts of the Caribbean (that is, Haiti and the Dominican Republic). The prevalence of chronic HBV infection is intermediate (2% to 7%) in south central and southwest Asia, Israel, Japan, eastern and southern Europe, Russia, most areas surrounding the Amazon River basin, Honduras, and Guatemala. In northern and western Europe, North America, Australia, New Zealand, Mexico, and southern South America, chronic HBV infection prevalence is low (<2%) in the general population. Map 3-3--Geographic Distribution of Hepatitis B Prevalence, 2000. Hepatitis B Surface Antigen Prevalence >8% — High 2-7% — Intermediate <2% — Low Risk for Travelers The risk of HBV infection for international travelers is generally low, except for certain travelers in countries with intermediate or high HBV endemicity. Factors to consider in assessing risk include (1) the prevalence of chronic HBV infection in the local population; (2) the extent of direct contact with blood or secretions, or of sexual contact with potentially infected people; and (3) the duration of travel. Preventive Measures Vaccine HBV vaccination is currently recommended for all people who work in health care fields (medical, dental, laboratory, or other) that entail exposure to human blood. HBV vaccination should be considered for travelers who plan to reside for 6 months or longer in areas with intermediate to high levels of endemic HBV transmission (that is, with HBV surface antigen [HbsAg] prevalence >2%) and who will have any of the previously discussed types of contact with the local populations. In particular, travelers who anticipate sexual contact or who will have daily physical contact with the local population; or who are likely to seek medical, dental, or other treatment in local facilities; or any combination of these activities during their stay should be advised to receive the vaccine. Those who will be traveling for less than 6 months should also be vaccinated if they will have direct contact with blood, or sexual contact with residents of areas with intermediate to high levels of endemic HBV transmission. Two types of HBV vaccines have been licensed in the United States. One, which was manufactured from the plasma of people with chronic HBV infection, is no longer produced in the United States. The remaining available type of vaccine is produced through recombinant deoxyribonucleic acid (DNA) technology by common baker's yeast into which the gene for HbsAg has been inserted. This type of HBV vaccine has been shown to be very safe when given to people of all ages. The usual schedule of primary vaccination consists of three intramuscular doses of vaccine. The recommended dose varies by product and the recipient's age (Table 3-7). The vaccine is usually administered as a three-dose series on a 0-, 1-, and 6-month schedule. The second dose should be given 1 month after the first dose; the third dose should be given at least 2 months after the second does and at least 4 months after the first dose. Alternatively, the vaccine produced by GlaxoSmith-Kline licensed to be administered on a four-dose schedule at 0, 1, 2, and 12 months. There is also a two-dose schedule for a vaccine produced by Merck & Co., Inc. that has been licensed for children and adolescents 11 through 15 years of age. Using the two-dose schedule, the adult dose of Recombivax-HB® is administered, with the second dose given 4 to 6 months after the first dose. Table 3-7.--Recommended Doses of Currently Licensed Hepatitis B Vaccines.GroupDose Recombivax-HB®*Engerix-B®* All infants (regardless of mother’s HBsAg status), children, adolescents, and adults, birth through 19 years of age.5 µg10 µg Adults 20 years of age or older.†10 µg20 µg Dialysis patients and other immunocompromised people.40 µg§40 µg¶ µg = microgram. * Both vaccines are routinely administered in a three-dose series. Engerix-B® also has been licensed for a four-dose series administered at 0, 1, 2, and 12 months. † Recombivax-HB® is now approved in a two-dose schedule for 11- through 15-year-olds (see “Preventive Measures”). § Special formulation (40 µg in 1.0 milliliters). ¶ Two 1.0 milliliter doses given at one site, in a four-dose schedule at 0, 1, 2, 6 months. Vaccination should ideally begin at least 6 months before travel so the full vaccine series can be completed prior to departure. Because some protection is provided by one or two doses, the vaccine series should be initiated, if indicated, even if it cannot be completed prior to departure. However, optimal protection is not conferred until after the final vaccine dose. There is no evidence of interference between HBV vaccine and other simultaneously administered vaccine(s) or with immune globulin. The optimum site of injection in adults is the deltoid muscle; vaccination in the buttocks results in poorer antibody response. Long-term studies of healthy adults and children indicate that immunologic memory remains intact for at least 15 years and confers protection against chronic HBV infection, even though HBV surface antibody (anti-HBVs) levels can become low or decline below detectable levels. For children and adults whose immune status is normal, booster doses of vaccine are not recommended, nor is serologic testing to assess antibody levels necessary for most vaccinees. (See Vaccine Recommendations for Infants and Children for a discussion of the HBV immunization schedule for infants who will be traveling.) Adverse Reactions Pain at the injection site (3% to 29%) and elevated temperature >37.7° Celsius (>99.9° Fahrenheit) (1% to 6%) are the most frequently reported side effects among vaccine recipients. In placebo-controlled studies, these side effects were reported no more frequently among people receiving HBV vaccine than among people receiving placebo. Among children receiving both HBV vaccine and diphtheria-tetanus-pertussis (DTP) vaccine, these mild side effects have been observed no more frequently than among children receiving DTP vaccine alone. A low rate of anaphylaxis has been observed in vaccine recipients based on reports to the Vaccine Adverse Event Reporting System (VAERS) (with an estimated incidence of 1 case in 600,000 vaccine doses distributed); 2 anaphylaxis cases were in children. None of the people who developed anaphylaxis died; however, anaphylaxis can be fatal and HBV vaccine can, in very rare instances, cause a life-threatening hypersensitivity reaction in certain individuals. Therefore, further vaccination with HBV vaccine is contraindicated in people with a history of anaphylaxis after a previous dose of vaccine. In the United States, surveillance of adverse events has shown a possible association between Guillain-Barré syndrome (GBS) and receipt of the first vaccine dose of plasma-derived HBV vaccine in adults. However, analysis of GBS reported to the Centers for Disease Control and Prevention (CDC), U.S. Food and Drug Administration (FDA), and vaccine manufacturers for the estimated 2.5 million adults who received one or more doses of recombinant HBV vaccine from 1986 to 1990 did not demonstrate an association between receipt of recombinant vaccine and GBS. Case reports of other rare adverse events following HBV vaccination that have been published in the medical literature have included multiple sclerosis, optic neuritis, rheumatoid arthritis, type I diabetes, autoimmune disease, and alopecia. Most of these reported adverse events have been in adults and no studies have compared the frequency of occurrence of the purported vaccine-associated disease or syndrome with the frequency of occurrence in an unvaccinated population. Analysis of reports to the VAERS has not found an increased frequency of adverse events among children since implementation of routine infant HBV vaccination. Any presumed risk of adverse events associated with HBV vaccination must be balanced with the expected 5,000 deaths from HBV-related liver disease that would occur in the United States each year without immunization, assuming a 5% lifetime risk of HBV infection. Surveillance for vaccine-associated adverse events will continue to be an important part of HBV vaccination programs in spite of the current record of safety. Precautions and Contraindications On the basis of limited data, there is no apparent risk of adverse events to the developing fetus when HBV vaccine is administered to pregnant women. The vaccine contains noninfectious HBsAg particles and should cause no risk to the fetus. HBV infection affecting a pregnant woman can result in serious disease for the mother and chronic infection for the newborn. Therefore, neither pregnancy nor lactation should be considered a contraindication for vaccination. Other Behavioral preventive measures are similar to those for human immunodeficiency virus and acquired immunodeficiency syndrome (see "Acquired Immunodeficiency Syndrome (AIDS)"). For more information on hepatitis B, see: http://www.cdc.gov/ncidod/diseases/hepatitis/b/fact.htm