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WASHINGTON, Dec. 16 /PRNewswire/ -- Results from a new study presented
today found that vaccinating all children against hepatitis A at 18 and 24
months in one Israeli community reduced overall incidence of the disease for
all ages by 95 percent. The study, authored by Ron Dagan, M.D., Director of
the Pediatric Infectious Disease Unit at Soroka University Medical Center,
Beer Sheva, Israel, was presented at the 45th Interscience Conference on
Antimicrobial Agents and Chemotherapy (ICAAC). Experts have long believed
that universal hepatitis A vaccination for children is an effective strategy
to reduce disease incidence. This study coincides with the recent unanimous
decision of the Advisory Committee on Immunization Practices (ACIP), an
advisory body to the Centers for Disease Control and Prevention (CDC),
recommending universal hepatitis A vaccination for all children between one
and two years of age. The ACIP recommendation marks a milestone in the fight
against the disease in the United States, particularly among toddlers who play
an important role in hepatitis A transmission.
Entitled "Universal Toddler Hepatitis A Virus Vaccination: An Opportunity
for the Elimination of Population Disparity in Disease Incidence," the study
by Dr. Dagan highlights the fact that before vaccination, one-fifth of all
toddlers in a hepatitis A endemic community had high hepatitis A antibody
levels indicating previous exposure. This was reduced by 90 percent within
three years after initiation of the toddler-only universal vaccination
program. In addition, a distinct disparity in hepatitis disease incidence
between the Jewish and non-Jewish population, related to differences in social
and economic living conditions, was practically eliminated, due to a very
impressive reduction in disease in both populations following vaccination.
"This study demonstrates the significant impact the hepatitis A vaccine
can have on the overall population," said Dr. Dagan. "Vaccinating all
toddlers not only resulted in a dramatic reduction of hepatitis A incidence in
an age group in Israel vulnerable to the disease, but also offers objective
proof of the rapid vaccination-induced reduction of hepatitis A circulation,
and the positive effect vaccination can have, on that community."
The study presented by Dr. Dagan follows the fluctuation in hepatitis A
incidence rates among the Israeli population. Since 1999, coinciding with the
introduction of the hepatitis A vaccine to all toddlers at 18 and 24 months,
overall levels of hepatitis A incidence have been reduced by 95 percent,
supporting the belief that the immunization of toddlers in the 18 to 24 month
bracket confers "herd immunity," the protection extended to family members and
the community in general when a large portion of a population is vaccinated.
In addition, the most significant decrease in hepatitis A levels after the
introduction of hepatitis A immunization in toddlers was seen in the one to
four year age bracket -- a demographic that is historically the most
susceptible to this type of infection. There was almost 100 percent
(98.5 percent) decrease in reported incidences among this demographic.
These findings are consistent with the recent study by Wasley et al
("Incidence of Hepatitis A in the United States in the Era of Vaccination,"
Journal of American Medical Association, July 13, 2005) which shows sustaining
and further reducing hepatitis A incidences in the United States can be
achieved by improving vaccination coverage in groups for which it is currently
recommended. Similar to the Israeli study, Wasley et al found that a decline
in hepatitis A infection rates in children occurred with the mandated
vaccination of one age group and helped reduce transmission in other age
groups, supporting the hypothesis of a strong herd immunity effect. Wasley et
al concluded that elimination of hepatitis A would require expansion of
current recommendations to include routine vaccination of all children. The
unanimous ACIP decision to recommend incorporating hepatitis A vaccination
into the childrens immunization schedule reinforces the need to improve and
enhance the health and well-being of children by helping to protect them from
this serious and highly contagious disease.
About Hepatitis A
Hepatitis A is a serious liver disease caused by the hepatitis A virus.
This virus is found in the stool of persons with hepatitis A and is spread by
close personal contact and by eating food or drinking water contaminated with
the hepatitis A virus. About one in five people with the disease have to be
hospitalized and up to 100 people with the disease may die each year in the
U.S. Symptoms of the disease can be debilitating and include fever, fatigue,
loss of appetite, nausea, abdominal discomfort, jaundice and dark urine.
GlaxoSmithKline provided editorial and media relations assistance for this
release.
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