Havrix
The following drug information is obtained from various newswires, published
medical journal articles, and medical conference presentations.
General Information
A new pediatric dose and vaccination schedule for Havrix has
been approved as treatment for hepatitis A. The additional
licensure from the Food and Drug Administration will enable
vaccination of children and adolescents, two through 18 years of
age, on the same schedule as is already available for adults.
The new schedule for children and adolescents will require one
less injection with Havrix than the initially licensed schedule,
and thus one less trip to the doctor's office. The new schedule
starts with a primary dose of 720 EL.U./0.5 ml, which affords
protection for up to one year. A booster dose, also 720 EL.U./0.5
ml, administered six to 12 months after the primary dose, is
recommended to extend protection. Previously, children and
adolescents required two primary doses of 360 EL.U./0.5 ml each, at
a one-month interval, followed by a booster dose of 360 EL.U./0.5
ml, six to 12 months after the first primary dose (this regimen
will continue to be available for those who have already started
with the primary injection).
Children and adolescents who have been started on the 360
EL.U./0.5ml dose of Havrix should complete the three-dose schedule
at that dose. Those who have not yet received any doses of Havrix
can begin vaccination with the 720 EL.U./0.5 ml dose on the
two-dose schedule.
Clinical Results
Havrix, initially licensed in the United States in February
1995, demonstrated high efficacy in clinical trials. Vaccination
induced production of antibodies in up to 98% of adults and in up
to 96% of children and adolescents within 15 days of the primary
injection.
Side Effects
The most common adverse events in clinical trials were injection
site soreness (56% of adults and 21% of children) and headache (14%
of adults and 9% of children). As with all vaccines, expanded
commercial use could reveal rare adverse events not observed in
clinical trials.
Additional Information
Hepatitis A is a highly contagious disease spread by the
fecal-oral route through close person-to-person contact or
ingestion of contaminated food or water. Among people two through
18 years old, symptoms tend to vary with age, ranging from
generally flu-like symptoms in young children to debilitating,
adult-like symptoms and possibly acute liver injury in adolescents.
The more serious symptoms include jaundice, fever, vomiting,
diarrhea, rash, and joint pain. On average, adults with hepatitis A
miss 30 days of work or routine daily activity.
Additionally, because children may not have symptoms
recognizable as hepatitis A, infection of children may serve to
initiate or perpetuate community-wide outbreaks. Several such
outbreaks are ongoing in the United States.
In the United States, there are an estimated 143,000 cases of
hepatitis A each year.
Children and adolescents at risk of hepatitis A include those
residing in communities experiencing outbreaks, belonging to
populations that experience cyclic hepatitis A epidemics, such as
native people of Alaska and the Americas, or traveling to areas
where the disease is endemic.