Hepatitis B virus under an electron microscope

March 8, 2017

Compared to the U.S.-born population, immigrants from many Asian countries, in which hepatitis B is endemic, are more likely to be exposed to and infected with hepatitis B, a viral infection that attacks the liver. A recent study by Dr. Sunmin Lee, associate professor in the Department of Epidemiology and Biostatistics, Dr. Hee-Soon Juon, professor at Thomas Jefferson University, and colleagues investigated the prevalence of hepatitis B infection and exposure among 600 foreign-born Chinese, Korean, and Vietnamese Americans in the Baltimore-Washington Metropolitan Area. The results were based on multiple hepatitis B screening tests, which have rarely been reported in previous studies in this population.

Specifically, three hepatitis B screening tests were administered, including tests for the hepatitis B surface antigen (HBsAg), hepatitis B surface antibody (anti-HBs), and total hepatitis B core antibody (anti-HBc). The hepatitis B surface antigen test indicates whether an individual is infected with the hepatitis B virus, the hepatitis B surface antibody test indicates whether an individual has developed immunity from having been exposed to the hepatitis B virus, and the total hepatitis B core antibody test indicates whether an individual with immunity from the hepatitis B virus had a previous or has an ongoing hepatitis B infection.

Among participants, 5.5% had a hepatitis B infection, 28% were immune due to a natural infection, 27.7% were immune due to vaccination, 28.5% were unprotected and susceptible to infection, and 10.3% had unclear hepatitis B screening results. Possible explanations for the unclear results offered by the authors are a resolved hepatitis B infection, false-positive total hepatitis B core antibody (anti-HBc) test, low chronic of infection, or resolving acute infection. Significant ethnic differences in hepatitis B exposure were found with Vietnamese Americans having the highest exposure (53.2%), then Korean Americans (43.4%), and lastly Chinese Americans (34.8%). 

The authors emphasize the importance of having these multiple hepatitis B screening tests given that “having information on anti-HBc allows us to identify past infection or vaccination history, so that we can assess the population’s current status or need and so that we can help public health professionals plan for educational programs or behavioral interventions.” As indicated by the positive total hepatitis B core antibody (anti-HBc) results, 44% of participants were found to have been exposed to the hepatitis B virus, which is about seven times higher than an estimate of 6% based on nationally representative data from the 2011-2012 National Health and Nutrition Examination Survey (NHANES). 

The authors suggest that “as the number of immigrants from Asia grows, it is important to recognize the HBV [hepatitis B virus] prevalence and HBV exposure among foreign-born Asian Americans, and to deploy early detection and follow-up efforts to treat chronic HBV infection in order to reduce liver cancer disparities caused by HBV infection."

 

Article Link: 
Hepatitis B Virus Infection and Exposure among Foreign-Born Asian Americans in the U.S.
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Sunmin Lee