Although more than 70 million people in the United States have been vaccinated against hepatitis B virus (HBV), more than 800,000 people are still estimated to be living with HBV across the country, according to results from the latest National Health and Nutrition Examination Survey (NHANES). The findings, recently published in the journal Hepatology, also show that nearly half of Americans affected today are of Asian descent, and that more than 70 percent of those affected by hep B are foreign-born, aidsmap reports.

Hep B can be effectively treated with interferon and antivirals, but these generally do not lead to a long-term cure. However, a preventive vaccine against hep B has been available worldwide since the early 1980s, and is now part of the routine childhood immunization series in many countries.

According to the NHANES, about 25 percent of the U.S. population has been vaccinated against hep B in the past 30 years, with up to 90 percent of young children today having vaccine-induced immunity. Nonetheless, the survey showed overall hep B prevalence has essentially remained the same nationwide since the late ’90s, largely due to increased immigration from places like East Asia and parts of Africa, where hep B is endemic.

Currently, hep B prevalence in the United States is about 0.3 percent. However, among black Americans, chronic HBV rates are reportedly 2- to 3-fold greater than that of the overall population. Among Asians, hep B rates are nearly 10 times higher, currently accounting for a prevalence of nearly 3 percent across the subpopulation.

Study authors said the findings help support recent recommendations from the U.S. Centers for Disease Control and Prevention and other federal agencies suggest that screening and vaccination programs for hep B should focus more extensively on foreign-born populations. The report also helps to explain why, despite a widespread vaccination push, overall hep B rates are still slow to fall in the United States.