WebMD Medical News
Louise Chang, MD
March 15, 2007 -- Reported illness from hepatitis A, hepatitis B, and
hepatitis C dropped dramatically in the U.S. from 1995 to 2005, hitting record
lows, says the CDC.
Reported acute cases of hepatitis A and hepatitis B haven't been this low
since the government started keeping hepatitis records in 1966.
Reported acute cases of hepatitis C are also at a record low, but those
records don't date back as far, according to the CDC.
Hepatitis is a liver disease caused by at least five different viruses, in
addition to its non-viral causes. Hepatitis A, B, and C are America's three
most common types of viral hepatitis.
Hepatitis infection doesn't always trigger immediate symptoms -- which can
include jaundice and abdominal pain -- and the CDC's new data doesn't include
people with hepatitis who have no symptoms.
" ... There are still a larger number of infections that are out there
than are caught by our surveillance," says CDC epidemiologist Annemarie
However, "The fact that we're seeing declining numbers of new
symptomatic cases indicates that the number of new infections is also
declining," Wasley, who works in the CDC's division of viral hepatitis,
The CDC estimates that about 113,000 people in the U.S. became infected with
one of these three hepatitis viruses in 2005.
The statistics appear in the CDC's Morbidity and Mortality Weekly Report:
Hepatitis confuses many people because there are so many different
Also, people with hepatitis often have no symptoms, although viral hepatitis
infections can be detected with a blood test.
Hepatitis A is an inflammation of the liver caused by infection with the
hepatitis A virus. Poor sanitary conditions and personal hygiene practices
contribute to spread of the disease.
Hepatitis A is not a chronic disease, and once you have gotten over a
hepatitis A infection, you can't get it again.
Unlike hepatitis A, hepatitis B and C can be chronic and can lead to
permanent liver damage, cirrhosis, liver failure, and liver cancer.
Inflammation of the liver can also be due to noninfectious causes of
hepatitis such as alcohol and certain medications.
In 2005, the CDC got reports of 4,488 people ill with hepatitis A. That
equals 1.5 cases per 100,000 people -- the lowest rate since the government
began tracking hepatitis in 1966.
That compares to an average of 28,000 cases of acute hepatitis A reported
each year from 1987-97.
Including the unreported cases, the CDC estimates 42,000 new cases of
hepatitis A infection in 2005.
Starting in 1999, 17 states have recommended hepatitis A vaccination for all
children. Those states saw a greater decline in reported childhood hepatitis A
illness than other states.
The CDC now recommends the hepatitis A vaccine for all children age 12-23
The hepatitis A vaccine is also recommended for people at high risk of
contracting the disease (including men who have sex with men, people who use
illegal drugs, people with chronic liver disease, and people traveling to
countries where the hepatitis A virus is common).
In 2005, the CDC received reports of 5,494 people ill with hepatitis B. That
translates to 1.8 cases per 100,000 people -- also a record low.
The CDC estimates there were 51,000 new cases of hepatitis B infection in
the U.S. in 2005, including unreported cases.
The decline in hepatitis B started in the mid-1980s and incidence of the
disease has dropped an estimated 80% since 1991, when the U.S. government
launched an effort to curb it.
The greatest drop in hepatitis B cases occurred in children less than 15
years old. Those kids were in the first generation of children for whom
universal vaccination against hepatitis B was recommended.
Wasley explains that the CDC only began tracking hepatitis cases that
weren't hepatitis A or B in 1982. Many of those combined cases were likely due
to hepatitis C.
The CDC began tracking hepatitis C separately in 1995, when a reliable test
for hepatitis C antibodies became widely available, Wasley says.
Reported cases of people ill with hepatitis C have dropped steadily since
peaking in the late 1980s.
There is no hepatitis C vaccine. The drop in reported cases of hepatitis C
is likely due to a decline in needle sharing among intravenous (IV) drug users,
according to the CDC.
IV drug use was the most common risk factor among the 671 hepatitis C cases
reported to the CDC in 2005.
"For hepatitis C, the majority of people with new infections are
asymptomatic," Wasley says. "We have a relatively small number of
symptomatic cases that we identify, but there are many, many other asymptomatic
infections that are occurring at the same time."
The CDC estimates there were about 20,000 new cases of hepatitis C infection
in the U.S. in 2005, including unreported cases.
SOURCES: CDC: Morbidity and Mortality Weekly Report: Surveillance
Summaries, March 16, 2007; vol 56: pp 1-25. Annemarie Wasley, ScD,
epidemiologist, Division of Viral Hepatitis, CDC. News release, CDC.
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