Slide 21. Hepatitis A
Let's switch to hepatitis A. When we think about hepatitis A in
children, we think about it as quite a self-limited illness. In
children less than 6 years of age, the illness is most often
asymptomatic in at least 70% of the cases. In the 30% of children who
do have symptoms, they tend to be mild, low-grade fever, malaise, and
anorexia. When children over 6 years of age acquire hepatitis, they
tend to get a more striking illness, and about 70% of them will
develop jaundice.
When adolescents or adults acquire hepatitis A, they develop a
memorable illness, which very often will last for weeks. Transmission
of hepatitis A is very easy, both within the day care setting as well
as in the household. Awareness of hepatitis A within a given
environment is very often signaled by the presence of a symptomatic
adult who has had contact with an asymptomatic child with hepatitis.
That symptomatic adult may be the parent of that child or may be a day
care worker.
Slide 22. Epidemiology of Hepatitis A
Hepatitis A is endemic in many parts of the world, and as a
consequence, acquisition of infection with hepatitis A is a concern
for the international traveler. The low-risk areas which have been
identified, places where it is unlikely to acquire hepatitis A,
include Japan, Australia, New Zealand, western Europe, and
Scandinavia. In contrast, the high-risk areas include large parts of
the world, eastern Europe, Africa, and Asia. Even within the United
States, there are several communities in which hepatitis A is endemic,
and those that are very striking include Native Americans, Alaskan
Eskimos, much of the Hispanic community, and the Hasidic Jewish
community.
Slide 23. Hepatitis A Vaccine
Slide 24. Hepatitis A Vaccine
Hepatitis A vaccine is indicated for children in communities that
have high rates of hepatitis A, and this includes any area that has an
annual average incidence that is twice the national incidence of
hepatitis A. It turns out that the national incidence of hepatitis A
is 10 cases per 100,000 population, and so a high-risk area in the
United States is considered to have more than 20 cases per 100,000
population. The areas in the United States where this is the case are
in the west and far west. The objective of using the hepatitis A
vaccine is to achieve a sustained reduction in the incidence of
hepatitis A.
There is not only enthusiasm for immunizing communities where the
rate of hepatitis A is more than 20 per 100,000 population, but there
is also a fair amount of enthusiasm for immunizing areas in which the
incidence of hepatitis A is between 10 and 20 per 100,000 population.
If we look at those areas we find that, for the most part, they too
are in the western United States.
Slide 25. Average Reported Cases of Hepatitis A per
100,000 Population: 1987-1997
Slide 26. Average Reported Cases of Hepatitis A per
100,000 Population: 1987-1997
This map shows the average reported cases of hepatitis A per
100,000 population for the decade 1987 to 1997, and we see in the
deepest orange those areas in which the rate of hepatitis A is more
than 20 cases per 100,000 population. Here is a little map of Florida
in which we see there are only 2 counties in which the incidence of
hepatitis A exceeds 20 per 100,000 population, and in the next deepest
orange, there are those counties in which the rate of hepatitis is
between 10 and 20 per 100,000 population.
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