Viral Hepatitis Surveillance United States, 2014
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Viral Hepatitis Surveillance United States, 2014 Revised 9/26/16: The counts and rates for acute hepatitis B have been updated. Surveillance for Viral Hepatitis — United States, 2014 Contents SUMMARY ................................................................................................................................................. 3 BACKGROUND ........................................................................................................................................... 3 Sources of Information.......................................................................................................................... 8 Adjustments to Reported Cases from the National Notifiable Diseases Surveillance System ............. 8 Investigation of Healthcare-Associated Outbreak Cases .................................................................... 11 HEPATITIS A ............................................................................................................................................. 12 HEPATITIS B ............................................................................................................................................. 24 Acute Hepatitis B ................................................................................................................................ 24 Chronic Hepatitis B ............................................................................................................................. 35 HEPATITIS C ............................................................................................................................................. 42 Acute Hepatitis C ................................................................................................................................ 42 Hepatitis C, Past or Present ................................................................................................................. 53 DISCUSSION ............................................................................................................................................. 60 ADDITIONAL RESOURCES ........................................................................................................................ 65 2 Division of Viral Hepatitis, CDC Surveillance of Viral Hepatitis – United States, 2014 SUMMARY As part of the Centers for Disease Control and Prevention’s (CDC) National Notifiable Diseases Surveillance System (NNDSS) (1), viral hepatitis case-reports are received electronically from U.S. state and territorial health departments via CDC’s National Electronic Telecommunications System for Surveillance (NETSS), a computerized public health surveillance system that provides CDC with data on a weekly basis. Although the surveillance infrastructure was in place for states to report both acute and chronic infections, case-reports of chronic hepatitis B virus (HBV) and past or present hepatitis C virus (HCV) infections, which account for the greatest burden of disease, were not submitted by all states; in 2014, 40 states submitted reports of chronic HBV infection and 37 states submitted reports of chronic HCV infection. The NNDSS data in this report should be interpreted with the understanding that “reported cases” of viral hepatitis represent persons who were tested for and diagnosed with viral hepatitis infection based on a relatively stringent case definition. Because most infections with viral hepatitis are asymptomatic, all cases are not identified or reported. As a result, this Summary is most useful in detecting trends over time for newly reported cases of hepatitis A virus (HAV), HBV, and HCV infections. However, to account for under-ascertainment and under-reporting, an estimation method was developed in 2011 to better quantify the number of new cases of hepatitis A, B, and C from the actual number of cases reported for each disease (2). The estimates in this report were derived from this methodology. We therefore caution the reader that estimates before 2011, which were obtained using a different, unpublished methodology, cannot be compared with those from 2011 to the present. With progressive infant hepatitis A vaccination recommendations since 1996 and universal infant vaccination since 2006, vaccination rates and evidence of vaccine-induced immunity in young persons have increased in the past decade (3,4). Despite protection among young persons, many older adults have not been vaccinated and are therefore susceptible to infection. From 2011 to 2013, an increase in the number of reported cases of hepatitis A was observed. However in 2014, a total of 1,239 cases of hepatitis A were reported, representing a 30.4% decrease from 2013. This decline was the result of a large 2013 hepatitis A outbreak among persons who consumed imported pomegranate seeds in several southwestern states and Hawaii (5). After adjusting for under-ascertainment and under-reporting (2), the estimated number of new HAV infections in 2014 was 2,500. Acute hepatitis B has been declining in incidence since 1990 mainly due to effective vaccination strategies. The number of reported cases of acute hepatitis B has remained relatively stable since 2009. A total of 2,791 acute cases were reported in 2014. However, chronic HBV infection remains a major public health challenge; recent CDC investigations report approximately 850,000 HBV-infected persons in the United States (6, 7), although other studies have estimated that as many as 2.2 million persons are living with HBV infection (8). Surveillance data from enhanced surveillance sites in this report indicate about one-half of chronic HBV infections were among Asians/Pacific Islanders, and 71.3% of chronic HBV infections were among persons born 3 Surveillance for Viral Hepatitis — United States, 2014 outside of the United States. Other data indicate that approximately 47%–70% of persons with HBV infection living in the United States were born in other countries (9). Among foreign-born persons with chronic HBV infection, an estimated 58% migrated from Asia (8). Further, mortality data in this report show that disproportionate numbers of Asians/Pacific Islanders are dying with hepatitis B. Identifying these chronically infected persons and linking them to care is critical (10, 11). The U.S. Preventive Services Task Force (USPSTF) joined with CDC in 2014 to recommend HBV testing for persons born in countries where HBV infection is endemic (12). After adjusting for under-ascertainment and under-reporting (2), the estimated number of new HBV infections in 2014 was 18,100. After receiving reports of cases of acute hepatitis C ranging from 781-877 during the years 2006–2010, reported cases of acute HCV infection increased more than 2.5 times from 2010– 2014. Cases of acute HCV infection rose annually, from 850 in 2010 to 1,232 in 2011, 1,778 in 2012, 2,138 in 2013, and 2,194 in 2014. The increase from 2010–2014 is thought to reflect both true increases in incidence and, to a lesser extent, improved case ascertainment. Based on new epidemiologic studies, at least 4.6 million persons are HCV-antibody positive and approximately 3.5 million are currently infected with HCV (13). New cases of HCV infection are predominately among young persons who are white, live in non-urban areas (particularly in Eastern and Midwestern states), have a history of injection-drug use, and previously used opioid agonists such as oxycodone (14). Improved case ascertainment by Florida, Massachusetts, and New York, which were funded by CDC to conduct enhanced surveillance, partially explains the increased incidence of acute HCV infection in these states. In other locations where the number of cases has increased markedly ( e.g., Kentucky, Tennessee, Virginia, and West Virginia), increases have occurred without any federal support for investigation or follow-up, reflecting overall increases in incidence (15, 16). After adjusting for under-ascertainment and under-reporting (2), an estimated 30,500 new HCV infections occurred in 2014. Mortality among HCV-infected persons—primarily adults aged 55–64 years—is increasing (17, 18). For the first time in the United States (17), in 2007 the number of HCV-related deaths (n=15,106) exceeded the number of HIV/AIDS-related deaths (n=12,734) (17) and has since continued to increase. The number of HCV-related deaths rose to 19,659 in 2014 and more than one-half of deaths occurred among persons aged 55-64 years. A key public health challenge is to increase the proportion of persons tested, and of those who are currently infected, increase the proportion referred for care and treatment (10, 11). To address this challenge the USPSTF joined with CDC in 2013 to recommend one-time testing for HCV infection among adults born during 1945–1965 (19). 4 Division of Viral Hepatitis, CDC BACKGROUND Viral hepatitis is caused by infection with any of at least five distinct viruses: hepatitis A virus (HAV), hepatitis B virus (HBV), hepatitis C virus (HCV), hepatitis D virus (HDV), and hepatitis E virus (HEV). Most viral hepatitis infections in the United States are attributable to HAV, HBV, and HCV. All three of these unrelated viruses can produce an acute illness characterized by nausea, malaise, abdominal pain and jaundice, although many of these acute infections are asymptomatic or cause only mild disease. Thus, many persons infected with HBV or HCV are unaware they are infected and have clinically silent infections for decades until developing cirrhosis, end-stage liver disease, or hepatocellular carcinoma.