— Christine M. Kukka, Project Manager, HBV Advocate
For every one case of hepatitis B infection that is
reported to health authorities in the U.S., researchers predicts there
are 6.5 unreported, new infections among adults, which resulted in an
estimated 18,730 new hepatitis B infections nationwide in 2011.
New hepatitis B and C infections
are notoriously difficult to count. The infections may not cause
symptoms or sufficient side effects to prompt a newly-infected person
to see a doctor. Even when liver damage symptoms are present, the
doctor must diagnose it correctly, confirm the infection through blood
tests, and then report it accurately to local health authorities.
Because so many viral hepatitis
cases are missed, local health officials can miss outbreaks and they
often lack the information they need to design effective prevention and
treatment programs.
To try to tackle this
information void, researchers from the U.S. Centers for Disease Control
and Prevention's division of viral hepatitis crafted a model that
incorporated how many new infections would have been:
-
Symptomatic enough to require a doctor's visit
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Evident enough to be correctly diagnosed by a doctor
-
And, ultimately reported to health officials in 2011.
They used the number of hepatitis
cases reported to the National Notifiable Diseases Surveillance System
in their estimates. Their formula represents an updated approach to
estimating new infections. The last model developed was designed in the
1990s and depended on the experiences of blood transfusion recipients
who developed viral hepatitis. These new estimates are lower than what
has been used historically by CDC, but may be more accurate.
However, this model does not capture new hepatitis B infections that result from HBV-infected immigrants coming to the U.S.
"...These estimates should be
viewed as the best that can be generated at this time to support
surveillance, planning and prevention activities until better data sets
or more sophisticated models can be developed," researchers wrote in
the January edition of the American Journal of Public Health.
Their model also predicted:
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2,730 new hepatitis A infections in 2011, with two unreported cases for every reported case
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And, 17,100 new hepatitis C virus (HCV) cases annually, with 12.3 new infections for every reported case.
Labels: epidemiology, U.S.
