National surveillance is conducted for acute hepatitis A, B, and C viruses. During 1995--2005, rates of all three types of acute viral hepatitis declined dramatically. These declines partially resulted from implementation of comprehensive prevention strategies for each disease, including the introduction of effective vaccines against hepatitis A and hepatitis B. Created: 3/2/2007 by MMWR.
Date Released: 8/10/2007. Series Name: A Cup of Health with CDC.
A CUP OF HEALTH WITH CDC
The ABCs of Hepatitis
August 10, 2007
[Announcer] This podcast is presented by the Centers for
Disease Control and Prevention. CDC – safer,
[Matthew Reynolds] Welcome to A Cup of Health with CDC, a
weekly broadcast of the
MMWR, the Morbidity and Mortality Weekly Report. I’m your host, Matthew
Hepatitis can be a serious infection of the liver. In the United States, the
causes of hepatitis are hepatitis A virus or HAV, hepatitis B virus –
HBV, and hepatitis C
virus – HCV. Since 1981, we have had a vaccine for hepatitis B and by
1995 we also
had a vaccine for hepatitis A. Both vaccines are safe and effective and we’ve
remarkable drop in reported cases of hepatitis A and B. There is no vaccine
C, but even without a vaccine, we have also seen a drop in the number of cases
hepatitis C being reported. Here to discuss these recent trends is Dr. Annemarie
Wasley. Dr. Wasley is a researcher in CDC’s National Center for Hepatitis,
and TB Prevention and the lead author of a new study on the rates of hepatitis
United States. Welcome to the show, Dr. Wasley.
[Dr. Wasley] Thanks for inviting me, Matthew. It’s
a pleasure being here.
[Matthew Reynolds] Dr. Wasley, we’ve heard an introduction
to hepatitis. Can you tell
our listeners more about it?
[Dr. Wasley] Well, hepatitis is an illness of the liver,
as you mentioned. The word
“hepatitis” actually means inflammation of the liver, and it can
be caused by a variety of
things, including drugs, alcohol, some infections, and certain types of toxic
But in this podcast, we’re only going to be talking about viral hepatitis.
hepatitis that’s caused by the viruses that you mentioned. These three
Hepatitis A virus, hepatitis B virus, and hepatitis C virus account for most
new in the
U.S. HAV or hepatitis A virus causes a disease that’s self-limiting. By
that, we mean
that after people are sick, they get better on their own and then have lifelong
to infection. HBV and HCV are more complicated because these viruses can cause
chronic infection and people that are chronically infected have an increased
their lifetime of developing chronic liver disease or liver cancer.
[Matthew Reynolds] How do people get infected by these viruses?
I have the
impression that viruses can spread very quickly. Do the hepatitis viruses pass
person-to-person in the same ways?
[Dr. Wasley] Well, transmission of these viruses depends
on which virus we’re talking
about. HAV is probably the most easily transmitted of the three. That’s
spread by the fecal-oral route, which means that people get infected by ingesting
contaminated food or water that contains feces of an infected person. Typically,
spread through close personal contact, so that people like household members
contacts of an infected person are at particularly high risk of getting infected.
HBV and HCV, on the other hand, are a little more difficult to spread and this
it requires direct exposure to the blood or bodily fluids of an infected person.
when they get infected with HBV, they usually get infected either by having
sharing drugs with an infected person. Another way that people get infected
with HBV –
a pregnant woman can transmit the virus to her infant at the time of birth.
HCV is transmitted in a lot of the same ways that HBV is, but by far the most
way it’s transmitted these days is through injecting drug use; it accounts
for about 50%
of new cases. I do want to make clear though that neither HBV nor HCV is transmitted
through casual contact. For example, like coughing or hugging or sharing food
utensils or that kind of thing.
[Matthew Reynolds] I understand that there are different
viruses that cause hepatitis.
Are there differences in the symptoms someone would have, and how would a person
know if they have hepatitis?
[Dr. Wasley] Even though we’re talking about three
different viruses here, they all
cause similar symptoms when a person is first infected. You can’t tell
which virus is
infecting a person, based on their symptoms. A fair number of people, when they’re
infected, develop no symptoms at all, but when a person does get sick, it usually
pretty sudden or rapid onset, and one of the first characteristic signs is the
of jaundice, which is yellowing of the skin or the whites of the eyes. This
accompanied by a flu-like syndrome that would have symptoms like fever, nausea,
malaise. As I said, you can’t differentiate one virus from the other based
symptoms of the person, and so the only way of identifying which virus is causing
disease is through a blood test where they look for the antibody to HAV, HBV,
[Matthew Reynolds] I hear about hepatitis outbreaks from
time to time in the news,
and it seems like outbreaks are sometimes connected to restaurants. How often
outbreaks actually occur?
[Dr. Wasley] When you hear about outbreaks associated with
restaurants, those are
due to hepatitis A. As I mentioned before, you can get infected with hepatitis
consuming food that’s been contaminated, in this case, typically by an
handler. Fortunately, this type of outbreak is relatively uncommon in the U.S.,
does get a lot of media attention. In actuality, most of the hepatitis A in
U.S. is due to
person-to-person spread. In the past, we had large, community-wide outbreaks
hepatitis A, but now that we’ve got routine vaccination of children, these
becoming increasingly rare. However, we still do get outbreaks in high-risk
like drug users and men who have sex with men, and this sometimes can spread
the wider community.
For HBV and HCV, because these viruses are more difficult to spread, we don’t
get them in large outbreaks, like we did with hepatitis A. We do sometimes get
outbreaks or clusters of cases which occur in high-risk groups, such as injecting
users where the prevalence of infection is high, and sharing equipment, etc.,
[Matthew Reynolds] You recently completed a study looking
at the number of cases of
viral hepatitis in the United States during the years of 1995 to 2005. Are we
progress in containing these diseases?
[Dr. Wasley] Hepatitis A, B, and C are all reportable diseases,
which means that if a
doctor identifies a case, he’s supposed to report it to a local health
authority, who in turn
report it to us here at CDC. And from tracking those cases, we know that we’re
substantial progress in reducing the occurrence of all types of reportable viral
Hepatitis A used to be one of our most commonly reported infectious diseases,
average of about 28,000 cases identified each year, but with the introduction
vaccine in 1995, and then the development of recommendations for use of that
rates have dropped dramatically and we’ve now got the lowest rates ever
We’re also making substantial progress in reducing the occurrence of hepatitis
of Hepatitis B have declined by about 80% since 1991, when the first recommendations
were made for routine vaccination of all infants against hepatitis B, and we
the lowest rates of hepatitis B ever recorded. We do, however, still have high
specific risk groups, particularly among injecting drug users and individuals
Hepatitis C rates have also been falling since they peaked in the mid-1980s.
A lot of this
decline is likely due to changing behaviors among injecting drug users that
reduced their risk of getting not only HCV, but HIV and other bloodborne infections,
well. Primary prevention strategies like the screening and testing of blood
also undoubtedly contributing to this reduction in rates, as well.
[Matthew Reynolds] Dr. Wasley, since vaccines are available
for hepatitis A and B,
what are your recommendations about who should be vaccinated?
[Dr. Wasley] Hepatitis A vaccine is recommended, at this
point, for all U.S. children 12-
23 month of age. It’s also recommended for individuals with a risk factor
and that would be illegal drug users, men who have sex with men, and also international
travelers who are going to be going to countries where HAV is common.
Hepatitis B vaccine is also recommended for all U.S. children. Typically,
the first dose is
given to infants soon after birth. Hepatitis B vaccine is also recommended for
have a risk factor for infection. Again, injecting drug users, men who have
sex with men,
and also people that have had multiple sex partners or a recent history of a
transmitted disease. Hepatitis B vaccine is also routinely given to healthcare
and people that are receiving dialysis, because of their likely exposure –
exposure – to blood.
For hepatitis C, we don’t have a vaccine, so our prevention relies on
that are at increased risk for HCV, such as injecting drug users, and providing
counseling to them on how to avoid infection.
[Matthew Reynolds] Thank you, Dr. Wasley, for taking the time to talk with us
[Dr. Wasley] You’re welcome, Matthew. Thanks for inviting
[Matthew Reynolds] That’s it for this week’s
show. Don’t forget to join us next week.
Until then, be well. This is Matthew Reynolds for A Cup of Health with CDC.
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