Chapter 3Infectious Diseases Related To Travel
Hepatitis B is a disease caused by hepatitis B virus (HBV), a small, circular, partially double-stranded DNA virus in the Hepadnaviridae family.
HBV is transmitted by contact with contaminated blood, blood products, and other body fluids (such as semen). Activities associated with transmission include any that may increase the likelihood of contaminated blood or body fluid exposure. Travelers may be at increased risk due to engaging in casual and unprotected sex, having medical procedures in areas where blood may not be screened, or even through obtaining tattoos or having acupuncture.
An estimated 240 million people have chronic HBV infection globally (Map 3-04). Nevertheless, no data show the specific risk of infection with HBV among US travelers. Published reports of travelers acquiring hepatitis are rare, and the risk for travelers who do not have high-risk behaviors or exposures is low. The risk for HBV infection in travelers may be higher in countries where the prevalence of chronic HBV infection is high or intermediate; expatriates, missionaries, and long-term development workers may be at increased risk for HBV infection in such countries. All travelers should be aware of how HBV is transmitted and take measures to minimize their exposures.
Map 3-04. Prevalence of chronic hepatitis B virus infection among adults1,2
1 Used with permission from: Ott JJ, Stevens GA, Groeger J, Wiersma ST. Global epidemiology of hepatitis B virus infection: new estimates of age-specific seroprevalence and endemicity. Vaccine. 2012.30(12):2212–9.
2 This map shows the prevalence of chronic HBV infection among adults (aged 19–49 years) globally in 2005; because this analysis grouped countries together regionally, individual country prevalence may be higher or lower than reflected on the map.
HBV infection primarily affects the liver. Typically, the incubation period for hepatitis B is 90 days (range, 60–150 days). The usual signs and symptoms include malaise, fatigue, anorexia, nausea, vomiting, abdominal pain, and jaundice. In some cases skin rashes, joint pain, and arthritis may occur. Among people aged ≥5 years, 30%–50% will develop signs and symptoms during acute infection. In children aged <5 years and immunocompromised adults, acute HBV infection is typically asymptomatic. The overall case-fatality ratio of acute hepatitis B is approximately 1%.
Acute hepatitis B progresses to chronic HBV infection in 30%–90% of people infected as infants or young children and in <5% of people infected during adolescence or adulthood. Chronic infection with HBV may result in chronic liver disease, including cirrhosis and liver cancer.
Serologic markers specific for hepatitis B are necessary to diagnose HBV infection and to identify the stage of infection (Table 3-03). These markers can be used to differentiate between acute, resolving, and chronic infection.
Table 3-03. Interpretation of serologic test results for hepatitis B virus infection1
|HBsAg2||TOTAL ANTI-HBc||IgM ANTI-HBc||ANTI-HBs|
|+||–||–||–||Early acute infection; transient (up to 18 days) after vaccination|
|–||+||+||+ or -||Acute resolving infection|
|–||+||–||+||Recovered from past infection and immune|
|–||+||–||–||False-positive (susceptible); past infection; occult infection;3 or passive transfer of anti-HBc to infant born to HBsAg-positive mother|
|–||–||–||+||Immune if concentration is ≥10 mIU/mL after vaccine series completion; passive transfer after hepatitis B immune globulin administration|
Abbreviations: HBsAg, hepatitis B surface antigen; anti-HBc, antibody to hepatitis B core antigen; anti-HBs, antibody to hepatitis B surface antigen.
1From: 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 II: immunization of adults. MMWR Recomm Rep. 2006 Dec 8;55(RR-16):1–33.
2To ensure that an HBsAg-positive test result is not a false positive, samples with reactive HBsAg results should be tested with a licensed neutralizing confirmatory test, if recommended in the manufacturer’s package insert.
3People positive only for anti-HBc are unlikely to be infectious except under unusual circumstances in which they are the source for direct percutaneous exposure of susceptible recipients to large quantities of virus (such as blood transfusion or organ transplant).
No specific treatment is available for acute hepatitis B. Supportive treatment, including hospitalization, may be indicated for some people with severe clinical manifestations. Antiretroviral drugs are approved to treat chronic hepatitis B.
Indications for Use
Hepatitis B vaccination should be administered to all unvaccinated people traveling to areas with intermediate to high prevalence of chronic hepatitis B (HBV surface antigen prevalence ≥2%). Complete vaccination recommendations are available at www.cdc.gov/vaccines/hcp/acip-recs/vacc-specific/hepb.html. Vaccination may be considered for all international travelers, regardless of destination, depending on the traveler’s behavioral risk as determined by the provider and traveler.
Hepatitis B vaccine (see Table 3-04) is usually administered as a 3-dose series on a 0-, 1-, 6-month schedule to achieve immunity. The second dose should be given ≥1 month after the first dose; the third dose should be given ≥2 months after the second dose and ≥4 months after the first dose. The third dose should not be given before age 24 weeks. Exceptions to this schedule are available with specific licensed products in the United States; Recombivax HB (Merck & Co.) is licensed for a 2-dose schedule for children aged 11–15 years, and Engerix-B (GlaxoSmithKline) is licensed for a 4-dose schedule (0, 1, and 2 months, plus a 12-month booster). Combination vaccines including hepatitis B are available for children, and a combination hepatitis A and hepatitis B vaccine, Twinrix (GlaxoSmithKline), is also licensed in the United States. Consult the prescribing information when administering alternate schedules and formulations. Vaccination series started with one brand may be completed with another brand. Protection from the primary vaccination series is robust, and >95% of healthy people achieve immunity with the 3-dose series. Serologic testing and booster vaccination are not recommended before travel for immunocompetent adults who have been previously vaccinated.
Ideally, hepatitis B vaccination should begin ≥6 months before travel so the full vaccine series can be completed before departure. Because some protection is provided by 1 or 2 doses, the vaccine series should be initiated, if indicated, even if it cannot be completed before departure. Optimal protection, however, is not conferred until after the final vaccine dose is received, and travelers should be advised to complete the vaccine series. An approved accelerated vaccination schedule can be used for people traveling on short notice who face imminent exposure or for emergency responders to disaster areas. The accelerated vaccination schedule calls for vaccine doses administered at days 0, 7, and 21–30; a booster should be administered at 12 months to promote long-term immunity. A combined hepatitis A and hepatitis B vaccine can also be used on the same 3-dose schedule (0, 7, 21–30 days).
Vaccine Safety and Adverse Reactions
Hepatitis B vaccines are safe for people of all ages. Pain at the injection site (3%–29%) and fever (temperature >99.9°F [37.7°C]; 1%–6%) are the most frequently reported side effects among vaccine recipients. Hepatitis B vaccines should not be administered to people with a history of hypersensitivity to any vaccine component, including yeast. The vaccine contains a recombinant protein (hepatitis B surface antigen) that is noninfectious.
Limited data indicate no apparent risk of adverse events to the mother or the developing fetus when hepatitis B vaccine is administered to pregnant women. HBV infection affecting a pregnant woman can result in serious disease for the mother and chronic infection for the newborn. Neither pregnancy nor lactation should be considered a contraindication for vaccination.
Personal Protection Measures
As part of the pre-travel education process, all travelers should be counseled and given information about the risks for hepatitis B and other bloodborne pathogens from contaminated equipment or items used during medical, dental, or cosmetic procedures; blood products; injection drug use; any activities or procedures that involve piercing the skin or mucosa; or unprotected sexual activity, and should be informed about prevention measures. When seeking medical or dental care or cosmetic procedures (such as tattooing or piercing), travelers should be alert to the use of equipment that has not been adequately sterilized or disinfected, reuse of contaminated equipment, and unsafe injecting practices (such as reuse of disposable needles and syringes). HBV and other bloodborne pathogens can be transmitted if tools are not sterile or if personnel do not follow proper infection control procedures. Travelers should consider the health risks when receiving medical or dental care. The health risks should be strongly considered when deciding to obtain a tattoo or body piercing in areas where adequate sterilization or disinfection procedures might not be available or practiced.
CDC website: www.cdc.gov/hepatitis/HBV
Table 3-04. Vaccines to prevent hepatitis B
|VACCINE||TRADE NAME (MANUFACTURER)||AGE (Y)||DOSE||ROUTE||SCHEDULE||BOOSTER|
|Hepatitis B vaccine, recombinant1||Engerix-B (GlaxoSmithKline)||
0.5 mL (10 μg HBsAg)
0.5 mL (10 μg HBsAg)
1.0 mL (20 μg HBsAg)
1.0 mL (20 μg HBsAg)
1.0 mL (20 μg HBsAg)
0, 1, 6 mo
|Hepatitis B vaccine, recombinant1||Recombivax HB (Merck & Co., Inc.)||
0.5 mL (5 μg HBsAg)
1.0 mL (10 μg HBsAg)
1.0 mL (10 μg HBsAg)
0, 1, 6 mo
|Combined hepatitis A and B vaccine||Twinrix (GlaxoSmithKline)||
1.0 mL (720 ELU HAV + 20 μg HBsAg)
same as above
0, 1, 6 mo
0, 7, 21–30 d
Abbreviations: HBsAg, hepatitis B surface antigen; IM, intramuscular; ELU, ELISA units of inactivated HAV; HAV, hepatitis A virus.
1Consult the package insert for differences in dosing for hemodialysis and other immunocompromised patients.
- CDC. Recommended adult immunization schedule—United States, 2012. MMWR. 2012;61(4):1–7.
- CDC. Updated US Public Health Service guidelines for the management of occupational exposures to HBV, HCV, and HIV and recommendations for postexposure prophylaxis. MMWR Recomm Rep. 2001 Jun 29;50 (RR-11):1–42.
- Connor BA, Patron DJ. Use of an accelerated immunization schedule for combined hepatitis A and B protection in the corporate traveler. J Occup Environ Med. 2008 Aug;50(8):945–50.
- Croughs M, Van Gompel A, de Boer E, Van Den Ende J. Sexual risk behavior of travelers who consulted a pretravel clinic. J Travel Med. 2008 Jan–Feb;15(1):6–12.
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- Lok AS, McMahon BJ. Chronic hepatitis B: update of recommendations. Hepatology. 2004 Mar;39(3):857–61.
- Mast EE, Margolis HS, Fiore AE, Brink EW, Goldstein ST, Wang SA, et al. 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. MMWR Recomm Rep. 2005 Dec 23;54 (RR-16):1–31.
- Mast EE, Weinbaum CM, Fiore AE, Alter MJ, Bell BP, Finelli L, et al. 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 II: immunization of adults. MMWR Recomm Rep. 2006 Dec 8;55 (RR-16):1–33.
- Ott JJ, Stevens GA, Groeger J, Wiersma ST. Global epidemiology of hepatitis B virus infection: new estimates of age-specific HBsAg seroprevalence and endemicity. Vaccine. 2012 Mar 9;30(12):2212–9.
- Simonsen L, Kane A, Lloyd J, Zaffran M, Kane M. Unsafe injections in the developing world and transmission of bloodborne pathogens: a review. Bull World Health Organ. 1999;77(10):789–800.
- Sonder GJ, van Rijckevorsel GG, van den Hoek A. Risk of hepatitis B for travelers: is vaccination for all travelers really necessary? J Travel Med. 2009 Jan–Feb;16(1):18–22.
- Van Damme P, Ward J, Shouval D, Wiersma S, Zanetti A. Hepatitis B vaccines. In: Plotkin SA, Orenstein WA, Offit PA, editors. Vaccines. 6th ed. Philadelphia: Saunders Elsevier; 2012. p. 205–34.
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