Chronic Hepatitis B Infection and Vaccine Coverage
Chronic Hepatitis B Infection and Vaccine Coverage
Abstract & Commentary
By Lin Chen, MD
Assistant Clinical Professor, Harvard Medical School; Director, Travel Resource Center, Mount Auburn Hospital, Cambridge, MA
Dr. Chen reports no financial relationship relevant to this field of study.
Synopsis: Chronic hepatitis B infection is prevalent among Asians and Pacific Islanders tested in New York City, and screening of these populations should be routine. Immunization of all susceptible persons should be encouraged.
Source: CDC. Screening for Chronic Hepatitis B Among Asian/Pacific Islander Populations—New York City, 2005. MMWR Morb Mortal Wkly Rep. 2006;55:505-509.
The Asian American Hepatitis B Program conducted a hepatitis B serological survey in New York residents who were born in Asia or the Pacific Islands. The program tested 1836 persons from January 22 to June 30, 2005, including 925 persons aged ≥ 20 years who reported no previous HBV tests. HBsAg positivity was considered chronic HBV, and positive anti-HBV, with negative HBsAg, was considered resolved HBV.
Participants were primarily born in China (61.2%) or South Korea (30.3%). Other Asian countries (Bangladesh, Burma, Indonesia, Malaysia, Vietnam) comprised 7.4%. Half the patients reported living in the United States for more than 10 years. The majority (76.6%) had no health insurance, and 13.3% had a family history of HBV.
Among the 925 newly tested individuals, 14.8% had chronic HBV. Among those tested, 53.6% had resolved HBV infection and 31.6% were susceptible. The prevalence was higher among males, persons aged 20-39 years, and those who arrived in the United States within 5 years. The prevalence of chronic HBV was highest among persons born in China (21.4%), followed by South Korea (4.6%) and other Asian countries (4.3%). The follow-up rate was high at > 90%.
Commentary
HBV is a DNA virus in the Hepadnaviridae family, and is transmitted through exposure to blood or body fluids. Following mucosal or percutaneous exposure, an individual can have symptomatic or asymptomatic infection, although the latter is more common in children.1 Serum markers can be detected after an incubation period of 4-10 weeks, but clinical symptoms usually present 2-5 months after exposure.1 Although acute HBV infection can be severe, chronic infection leads to the majority of serious sequelae, including cirrhosis and hepatocellular carcinoma.
Three hundred-fifty to 400 million persons worldwide are chronic HBV carriers, and one million persons die annually from cirrhosis and hepatocellular carcinoma.2 The World Health Organization recommended universal hepatitis B vaccination for infants in 1992. In the United States, 200,000-300,000 new cases of hepatitis B were reported annually before the initiation of the childhood hepatitis B immunization program in 1991, with an estimated 1-1.25 million chronic HBV carriers.3 The CDC reports a decline in the incidence of acute hepatitis B, which decreased from 8.5/100,000 in 1990 to 2.1/100,000 in 2004.4,5 Adults account for 95% of the 60,000 new infections in 2004, and the 18-49-year age group account for 80% of these infections.5 Among high-risk individuals in the 18-49-year age group, 45% had hepatitis B vaccine in 2004, an improvement from 30% in 2000.5 Coverage in the United States is highest in the 18-20-year age group, but declined with increasing age. This finding likely represents improved immunization due to school requirements or recommendations.
This report shows that the prevalence of chronic HBV infection in Asians and Pacific Islanders tested in NYC is 35 times that of the overall US rate.6 Acquisition is commonly from vertical (mother to child) transmission, or in early childhood in countries with high endemicity, and acquisition early in life leads to chronic liver disease, such as cirrhosis and hepatocellular carcinoma, in 15%-40% of infected individuals. Therefore, early screening, monitoring, and treatment are greatly beneficial. Furthermore, household contacts should be screened.4
Many foreign-born individuals are not routinely screened for HBV. Pre-travel screening for hepatitis B in Chinese immigrants seen in a Massachusetts travel clinic identified chronic HBV infection in 6% of the population that had had no previous testing.7 A pre-travel consultation provides an opportunity to screen individuals born in highly endemic countries.
High-risk adults, especially the age group of 18-49, should be targeted. Medical providers should routinely screen persons born in Asia and the Pacific Islands. Similarly, the HBV prevalence in other groups of foreign-born individuals reflects the prevalence in their countries of origin, and screening should be done routinely for individuals from countries with intermediate and high-endemicity.4 Finally, travel clinics can provide valuable services by screening immigrant travelers for chronic HBV and immunizing their susceptible patients.
Geographic Distribution of Chronic Hepatitis B Virus (HBV)
References
- Ganem D, Prince AM. Hepatitis B Virus Infection—Natural History and Clinical Consequences. N Engl J Med. 2004;350:1118-1129. Erratum in: N Engl J Med. 2004; 351:351.
- Kane M. Global Programme for Control of Hepatitis B Infection. Vaccine. 1995;13:S47-S49.
- Hepatitis B Virus: A Comprehensive Strategy for Eliminating Transmission in the United States Through Universal Childhood Vaccination. Recommendations of the Immunization Practices Advisory Committee (ACIP). MMWR Recomm Rep. 1991;40:1-25.
- Mast EE, et al. A Comprehensive Immunization Strategy to Eliminate Transmission of Hepatitis B Virus Infection in the Unites States: Recommendations of the Advisory Committee on Immunization Practices (ACIP) Part 1: Immunization of Infants, Children, and Adolescents. MMWR Morb Mortal Wkly Rep. 2005;54:1-31. Erratum in: MMWR Morb Mortal Wkly Rep. 2006;55:158-159.
- CDC. Hepatitis B Vaccination Coverage Among Adults—Unites States, 2004. MMWR Morb Mortal Wkly Rep. 2006;55:509-511.
- McQuillan GM, et al. Prevalence of Hepatitis B Virus Infection in the United States: The National Health and Nutrition Examination Surveys, 1976 Through 1994. Am J Public Health. 1999;89:14-18.
- Ooi WW, et al. Immunity to Hepatitis A and B in Indian and Chinese Immigrants Seen in a Travel Clinic in Massachusetts, USA. J Travel Med. in press.
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