Screening for Chronic Hepatitis B Among Asian/Pacific Islander Populations --- New York City, 2005

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Chronic hepatitis B virus (HBV) infection is the most common cause of cirrhosis and liver cancer worldwide. In Asian and western Pacific countries where HBV is endemic, estimated prevalence of chronic HBV infection ranges from 2.4%--16.0%, and liver cancer is a leading cause of mortality (1). Although population-based prevalence data for Asians/ Pacific Islanders (A/PIs) living in the United States are lacking, they are believed to constitute a sizeable percentage of persons with chronic HBV infection in the United States, a country of low endemicity (2). To assess the prevalence of chronic HBV infection among A/PI populations living in New York City, the Asian American Hepatitis B Program (AAHBP)* conducted a seroprevalence study among persons who participated in an ongoing hepatitis B screening, evaluation, and treatment program. The results indicated that approximately 15% of participants who had not been previously tested had chronic HBV infection; all were born outside the United States. Screening programs are needed in A/PI communities in the United States to identify persons with chronic HBV infection so that they can be referred for appropriate medical management to prevent cirrhosis and liver cancer and so that their susceptible household and sex contacts can receive hepatitis B vaccine.

The AAHBP is a collaboration of community groups and academic and community health centers in New York City that provides hepatitis B screening, vaccination, and treatment free of charge. AAHBP also provides educational programs to increase awareness of HBV infection among A/PI communities in New York City. AAHBP screening programs are held at 12 collaborating health-care centers and community sites that serve A/PI communities throughout New York City.

Beginning in 2005, participants in this study were offered free hepatitis B serologic testing at AAHBP screening events or on a drop-in basis at participating clinics. At the time of testing, demographic and epidemiologic information was collected using self-administered questionnaires in English, Chinese, or Korean, with the assistance of bilingual volunteers when necessary. Blood was collected by venipuncture and tested for hepatitis B surface antigen (HBsAg) and antibody to HBsAg (anti-HBs). Clinical evaluation and treatment were offered to persons infected with HBV. Hepatitis B vaccination was provided to persons susceptible to HBV infection.

Because AAHBP provided free treatment for chronic HBV infection to the uninsured, the screening program might have attracted a substantial number of persons seeking treatment for previously diagnosed chronic HBV infection. To avoid overestimation of prevalence, this analysis was restricted to 925 newly screened adult participants, defined as persons aged >20 years who reported no previous serologic testing for HBV. Chronic HBV infection was defined as a positive result of a test for HBsAg using commercially available test kits. Resolved HBV infection was defined as a positive result of a test for anti-HBs and a negative result of a test for HBsAg. Persons with negative results of tests for HBsAg and anti-HBs were considered susceptible to HBV infection. Data were analyzed in aggregate with all personal identifiers removed. The study was approved by the institutional review boards of New York University School of Medicine and the participating clinical centers.

During January 22--June 30, 2005, a total of 1,836 persons were tested for HBV infection through AAHBP. Among the 1,633 persons with complete demographic information, 1,614 (98.8%) identified a country in Asia or the western Pacific as their place of birth. Screening determined that 392 of 1,633 (24.0%; 95% confidence interval [CI] = 21.9%--26.1%) had chronic HBV infection, 791 (48.4%; CI = 46.0%--50.9%) had evidence of resolved HBV infection, and 450 (27.6%; CI = 25.4%--29.7%) were susceptible to HBV infection.

A total of 925 (56.6%) persons tested reported not having been screened previously for HBV infection. Median age was 45 years (range: 20--83 years), and 512 (55.4%) were male (Table). The majority of participants were born in China (566 [61.2%]) or South Korea (280 [30.3%]); 69 (7.4%) were born in other Asian countries (i.e., Bangladesh, Burma, Indonesia, Malaysia, or Vietnam). Among those providing such information, 50.6% (433 of 856) reported living in the United States for >10 years, 76.6% (650 of 849) lacked health insurance, and 13.3% (120 of 899) reported a family history of HBV infection.

Among the 925 newly screened participants, 137 had chronic HBV infection, yielding a prevalence of 14.8% (CI = 12.5%--17.1%), which was lower than the 40.7% (CI = 36.7%--44.7%) prevalence of chronic HBV infection among 237 of 582 participants who knew they had been tested previously. A total of 496 (53.6%; CI = 50.4%--56.8%) newly screened participants had evidence of resolved HBV infection, and 292 (31.6%; CI = 28.6%--34.6%) were susceptible to HBV infection. The prevalence of chronic HBV infection was higher among males compared with females (19.7% versus 8.7%; p<0.01), persons aged 20--39 years compared with those aged >40 years (23.2% versus 9.6%; p<0.01), and among persons who had been living in the United States for <5 years compared with those who had been living in the United States for >5 years (21.6% versus 13.5%; p<0.01) (Table). Prevalence of chronic HBV infection varied by country of birth, from 21.4% among those born in China, to 4.6% among those born in South Korea, to 4.3% among those born in other Asian countries; none of the 10 participants born in the United States had chronic HBV infection.

Among all 1,836 persons who participated in the screening program, 1,717 (93.5%) returned for their test results, including 397 (90.8%) of the 437 total participants with chronic HBV infection. Among the 397 participants, a total of 329 (82.9%) were referred to an AAHBP-affiliated clinic, and 34 (8.6%) were referred to their personal physician; referral information was not available for 34 (8.6%) persons. Of the 329 with chronic HBV infection referred to AAHBP-affiliated clinics, 274 (83.3%) completed an initial evaluation visit. A total of 505 (27.5%) participants were susceptible to HBV infection. The 1-, 2-, and 3-dose vaccination coverage rates for these 505 were 89.3%, 78.8%, and 69.3%, respectively.

Reported by: H Pollack, MD, K Wan, MPH, R Ramos, MPA, M Rey, MD, New York Univ School of Medicine, Center for the Study of Asian American Health; A Sherman, MD, H Tobias, MD, PhD, New York Univ School of Medicine, Dept of Medicine; T Tsang, MD, A Tso, MD, Charles B. Wang Community Health Center; P Korenblit, MD, Gouverneur Healthcare Svcs; S Son, PhD, Korean Community Svcs; E Poon, MD, New York Downtown Hospital, New York City. S Bialek, MD, B Bell, MD, Div of Viral Hepatitis, National Center for HIV, Viral Hepatitis, STDs, and Tuberculosis Prevention (proposed), CDC.

Editorial Note:

The findings in this report on a screening program conducted among a predominantly immigrant Asian population indicate that approximately 15% of newly tested persons living in New York City had chronic HBV infection. The prevalence among participants in the screening program was approximately 35 times that of the overall U.S. population (2). Half of those with chronic HBV infection had been living in the United States for more than 10 years. These persons likely acquired their infections in their countries of origin, where HBV infection is endemic and infections usually are acquired at birth or during early childhood. The majority of infected participants were successfully referred for medical evaluation and follow-up.

Although this study was limited to New York City, screening programs in Atlanta, Chicago, New York City, Philadelphia, and California have reported similar prevalences of chronic HBV infection (10%--15%) among A/PI immigrants to the United States (3--5). A smaller proportion of those born in South Korea, compared with those born in China, were documented with chronic HBV infection (3--5). In addition, hepatitis B serologic testing in other settings, including routine public health surveillance among pregnant women and in other clinical settings, has demonstrated the disproportionate burden of chronic HBV infection among A/PI and other immigrant populations (6,7; CDC, unpublished data, 2004).

Perinatal and child-to-child transmission are the most common modes of HBV transmission in Asia and other countries where HBV is endemic. Of persons who acquire chronic HBV infection at early ages, an estimated 15%--40% will subsequently have chronic liver disease, including cirrhosis and liver cancer. Therefore, persons with chronic HBV infection need to be identified so that they can receive counseling and appropriate medical management to reduce their risk for chronic liver disease (8). Some will benefit from treatment or screening to detect liver cancer at an early stage. To prevent spread of HBV infection, household and sex contacts should be tested for HBV infection and offered hepatitis B vaccination, where indicated (8).

Although members of A/PI communities in the United States generally are aware that HBV infection is associated with increased risk for liver cancer, fewer than half recognize that HBV infection is endemic among persons born in Asia (9,10). Hepatitis B screening programs in U.S. A/PI communities can be an effective means of identifying persons with chronic HBV infection and motivating them to seek medical care. An evaluation of a hepatitis B screening program for A/PI in California determined that 67% of those with chronic HBV infection sought follow-up with their medical providers (5). Approximately 71% of participants in the California program reported that, before participating in the screening program, testing for HBV had not been recommended, although 89% had a regular family physician.

The findings in this report are subject to at least two limitations. First, the participants, primarily Chinese and South Korean, might not be representative of the overall Asian population in New York City. However, the diverse demographics suggest that the screening program attracted a range of local Asian immigrant populations living in the neighborhoods where screenings were conducted. Second, the study was conducted only in New York City, and results only reflect the ethnic composition of the local Asian populations that participated in the screening program. Because HBV infection prevalence varies among Asian countries, the findings likely are generalizable only to populations with the same countries of origin.

In collaboration with state and local partners, CDC supports programs to prevent HBV infection in U.S. A/PI communities. Local health departments in New York City and San Francisco, two cities with large A/PI populations, conduct enhanced viral hepatitis surveillance for both acute and chronic hepatitis B. The Asian Liver Center of Stanford University^† has developed educational programs for A/PI youth and practitioners of traditional Chinese medicine. State and local health departments have successfully implemented vaccination strategies (e.g., achieving high vaccination coverage among children and adolescents and high rates of HBsAg screening among pregnant women) recommended by the Advisory Committee on Immunization Practices in 1991 to eliminate HBV transmission in the United States. Since 1991, acute hepatitis B incidence has declined sharply among U.S. A/PI populations, eliminating major health disparities in acute HBV infection (8). Additional information regarding acute and chronic HBV infection and prevention activities is available from CDC at http://www.cdc.gov/ncidod/diseases/hepatitis/index.htm.

U.S. A/PI populations are at disproportionately high risk for hepatitis B-related chronic liver disease and liver cancer. Public health agencies and medical providers who serve U.S. A/PI populations and other communities with high proportions of persons born in countries where HBV infection is endemic should promote educational campaigns and screening programs. Such programs should identify persons with chronic HBV infection so that they can receive appropriate counseling and treatment to prevent cirrhosis and liver cancer and so that their contacts can be screened and given treatment, counseling, or vaccination as appropriate. Programs such as the comprehensive, community-based screening and evaluation program described in this report can effectively reach persons at risk for chronic HBV infection.

This report is based, in part, on contributions by M-D Chang, PhD, L Ma, American Cancer Society; C Cho, W Bateman, MD, E Davis, J Aberg, MD, S Fuller, D Chen, PhD, J Charles, T Jasper, R Boyd, R Barclay, M Brown, J Donnelly, PhD, R Boorstein, MD, L Martin, MS, B Dixon, MBA, G Beltran, Bellevue Hospital; C Lee, S Seto-Yee, E Tse, D Hong, C Ham Ching Lin, R Lee, P Kwok, MD, B Cheng, Charles B. Wang Community Health Center; K Wells, ND, CM Abate, JD, M Chen, G Leacock, MD, Community Healthcare Network; J Park, Korean Community Svcs; Korean American Internal Medicine Doctor's Group; Korean American Nurse Assn of New York; L Yiu, L Chiang, S Wade, S Shi, MD, Gouverneur Healthcare Svcs; W Wang, W Chung, C Ho, J Guo, New York Downtown Hospital Chinese Community Partnership for Health; Y Chen, PhD, H Lupatkin, MD, G Villanueva, MD, G Rochford, A Fidelia, New York Univ School of Medicine; J Nolan, P Baker, R Luo, J Bute, D Hana Yi, H Ho-Asjoe, MPS, C Trinh-Shevrin, DrPH, MX Zhan, MD, New York Univ School of Medicine, Center for the Study of Asian American Health; S Friedman, MD, JR Zucker, MD, I Weisfuse, MD, K Mahoney, New York City Dept of Health and Mental Hygiene; and the New York City Council.

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