Hepatitis B Virus Secular Trends in the United States ( ada gambar )
Hepatitis has been reportable in the United States for many years.
Hepatitis B became reportable as a distinct entity during the 1970s, after
serologic tests to differentiate different types of hepatitis became widely
available.
The incidence of reported hepatitis B peaked in the mid-1980s, with about
26,000 cases reported each year. Reported cases have declined since that
time, and fell below 10,000 cases for the first time in 1996. The decline
in cases during the 1980s and early 1990s is generally attributed to
reduction of transmission among men who have sex with men and
injection-drug users, as a result of HIV prevention efforts. During
1990–2004, incidence of acute hepatitis B in the United States declined
75%. The greatest decline (94%) occurred among children and adolescents,
coincident with an increase in hepatitis B vaccine coverage. A total of
2,895 cases of hepatitis B were reported in 2012.
An estimated 800,000 to 1.4 million persons in the United States are
chronically infected with HBV, and an additional 5,000–8,000 persons become
chronically infected each year.
Before routine childhood hepatitis B vaccination was recommended, more than 80% of acute HBV infections occurred among adults. Adolescents accounted for approximately 8% of infections, and children and infants infected through perinatal transmission accounted for approximately 4% each. Perinatal transmission accounted for a disproportionate 24% of chronic infections.
In the United States in 2005, the highest incidence of acute hepatitis B was among adults aged 25–45 years. Approximately 79% of persons with newly acquired hepatitis B infection are known to engage in high-risk sexual activity or injection-drug use. Other known exposures (e.g., occupational, household, travel, and healthcare-related) together account for 5% of new infections. Approximately 16% of persons deny a specific risk factor for infection.
Although HBV infection is uncommon among adults in the general population (the lifetime risk of infection is less than 20%), it is highly prevalent in certain groups. Risk for infection varies with occupation, lifestyle, or environment. Generally, the highest risk for HBV infection is associated with lifestyles, occupations, or environments in which contact with blood from infected persons is frequent. In addition, the prevalence of HBV markers for acute or chronic infection increases with increasing number of years of high-risk behavior. For instance, an estimated 40% of injection-drug users become infected with HBV after 1 year of drug use, while more than 80% are infected after 10 years.
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