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Abstract & Commentary
Hepatitis B and C Screening
By Lin H. Chen, MD
Assistant Clinical Professor, Harvard Medical School and Director, Travel Medicine Center, Mt. Auburn Hospital, Cambridge, MA.
Dr. Chen has received research grants from the Centers for Disease Control and Prevention and Xcellerex.
Synopsis: Adults with private healthcare insurance in the US have suboptimal testing for chronic HBV and HCV. Clearly, increased awareness is needed regarding HBV and HCV infections, epidemiology, risk, and screening.
Source: Spradling PR, Rupp L, Moorman AC, et al. Hepatitis B and C virus infection among 1.2 million persons with access to care: Factors associated with testing and infection prevalence. Clin Infect Dis 2012;55(8):1047-55.
This observational cohort study was conducted among 1.25 million adults from 4 private US healthcare organizations (HCO): Geisinger Health System, Danville, Pennsylvania; Henry Ford Health System, Detroit, Michigan; Kaiser Permanente-Northwest, Portland, Oregon; Kaiser Permanente, Honolulu, Hawaii. The study included persons who had ≥1 clinical encounter during 2006-2008 and ≥12 months of follow-up before 2009. The data on infections from this cohort was compared with those from the National Health and Nutrition Examination Survey (NHANES).
Hepatitis B virus (HBV) testing was done on 18.8% of 866,886 persons without a previous diagnosis, resulting in a 1.4% positive rate. Hepatitis C virus (HCV) testing was done on 12.7% of 865,659 persons without previous diagnosis, resulting in 5.5% positive. Among persons with at least 2 abnormal serum alanine aminotransferase (ALT), less than half were tested for HBV or HCV. Tests found that Asians were most likely to be infected with HBV (adjusted OR 6.33 compared to whites) whereas persons aged 50-59 years were most likely to be infected with HCV (adjusted OR 6.04 compared to age <30 years). The investigators estimate from NHANES that nearly ½ of HCV and 1/5 of HBV infections still remain unidentified.
It is estimated that 1-2% of the US population has chronic HBV or HCV infection, about 3.5-5.3 million persons, or 3-5 times more frequent than HIV infection. Among them, about 800,000-1.4 million have chronic HBV while 2.7-3.9 million have chronic HCV.1 The last few years have brought advances in treatment for both HBV and HCV (for example, tenofovir, entecavir, telaprevir and boceprevir), and early therapy of chronically infected persons may provide sustained virologic response.
Both HBV and HCV are blood-borne infections. HBV can be transmitted vertically from infected mothers to infants during birth, as well as via sexual contact, sharing needles, and needle stick injuries. Foreign-born persons from endemic countries have an increased likelihood of being chronically infected. Asians and Pacific Islanders are the predominant groups of Americans with chronic HBV infection as well as having a disproportionately high incidence of hepatocellular carcinoma (HCC). However, African-American adults have the highest rate of acute infection, particularly in the South.1
HCV is usually transmitted via percutaneous blood exposure, including receipt of a blood transfusion before 1992 when testing for HCV became available, injection drug use, tattooing by unregulated shops, needle sticks, invasive procedures prior to universal precautions, and also sexual contact. African Americans and Hispanics have higher HCV infection rates than whites.1
Spradling and colleagues have demonstrated the low testing rates for HBV and HCV among large cohorts in the U.S. who have private health insurance. Their data substantiate the increased risk for HBV associated with Asian race. They also illustrate the low rate of HBV and HCV testing (14.9%) following determination of an elevated serum ALT, which only increases to 42-44% following a second elevated ALT.
Because more than half of new HBV infections diagnosed in the US were in foreign-born persons, the Centers for Disease Control and Prevention (CDC) expanded testing recommendations for HBV infection in 2008 to include persons born in countries with HBsAg prevalence of ≥2%. Despite this recommendation, and despite the demonstration of cost-effectiveness using 2% prevalence for screening chronic HBV, testing for HBV in the foreign-born has remained inconsistent. Many health care providers still lack knowledge about HBV infection, available tests, screening, and vaccination in these high-risk populations. The Boston Area Travel Medicine Network (BATMN), a research collaboration of 5 travel clinics in the greater Boston Area, found that only 25% of persons born in countries with HBV prevalence of ≥2% had been tested before their pre-travel consultations. An additional 11% of the at-risk travelers tested at the travel clinic visits led to new diagnosis of chronic HBV infection in 3.3%.9
Similarly, the CDC has recommended HCV testing for persons with possible exposures since 1998. However, risk-based testing strategy has yielded suboptimal results in identifying HCV-infected persons; a number of studies have found that providers lacked knowledge about HCV prevalence, natural history, diagnostic tests and treatment, and recommendations for testing. Moreover, only 55% of persons with HCV infection reported known exposure risk, and the remaining 45% reported no recognized exposure risk.10 In 2012, CDC also expanded routine screening for HCV infection to include persons born between 1945-1965.10
The Institute of Medicine has identified deficiencies in knowledge and awareness, surveillance, immunization, and services for viral hepatitis in the US, and recommended strategies to optimize prevention and control of HBV and HCV, policies fully endorsed by the Department of Health and Human Services and CDC.1,3,10 Early diagnosis of chronic HBV and HCV infections can lead to improved therapeutic response, lower viral loads, halt progression to cirrhosis, and prevent hepatocellular carcinoma. Immunization should also be recommended for non-immune persons at risk for HBV exposure, household members and sexual contacts of HBV-infected individuals.
Specialists in fields with expertise in hepatitis and who may evaluate patients for reasons such as international travel — including those in travel and tropical medicine, infectious diseases, and gastroenterology — can reach this broader population that needs to be screened. Through the collaboration of specialists with primary care providers, significantly improvement of screening in high-risk populations is achievable.