Emory is one of five sites nationwide selected by the Centers for
Disease Control and Prevention (CDC) to conduct a clinical trial
of an anthrax vaccination regimen. The study, which is now enrolling
volunteers, will use the anthrax vaccine licensed by the U.S. Food
and Drug Administration (FDA) in 1970. The new trial is designed
to test whether changing the injection method or decreasing the
number of doses affects the quality of the immune response or local
reactions to the vaccine.
Harry Keyserling, professor of pediatric infectious diseases, is
principal investigator for the Emory study. Other sites include
Baylor College of Medicine, the Mayo Clinic, the University of Alabama
at Birmingham and Walter Reed Army Medical Center.
Anthrax is a disease caused by the Bacillus anthracis germ,
and most often is found in cattle and sheep. Infection with anthrax
bacteria may cause skin sores and intestinal or lung illness that
is often serious and may be fatal. Individuals become infected with
anthrax when they eat or touch animal parts that contain the bacteria,
or when they eat, touch or breathe anthrax bacteria in the air or
on the ground.
The last human clinical trials of the anthrax vaccine were conducted
in the 1950s in goat mill workers and in the laboratory scientists
who studied the disease. In 1991, under the potential threat of
Iraqi biological weapons during the Gulf War, the U.S. military
began vaccinating soldiers headed to the Persian Gulf. A shortage
of vaccine (and an exhaustive vaccination schedule that stretched
over several years) required many soldiers to complete their anthrax
immunizations on the battlefield.
In 1998, after assessing the threat of biological weapons, the
Department of Defense required all U.S. armed forces to receive
the anthrax vaccine. More than 2 million people, mostly in the military,
have been immunized since FDA approval of the vaccine in 1970. Currently
the vaccine is recommended for those in the military who may be
exposed to germ warfare and for scientists who work with anthrax
in the laboratory.
The current FDA-approved course for the anthrax vaccine requires
an initial dose followed by injections after two weeks, four weeks,
six months, 12 months, 18 months, and a yearly booster thereafter.
These injections are given subcutaneously (under the skin), and
some vaccine recipients have experienced pain and swelling in the
arm where the vaccine was given. Investigators believe this local
reaction might be avoided if the vaccine were given in the muscle
of the arm. In 2000, Congress asked the CDC to study the method
of injection for the vaccine and the number of doses required.
Participants in the new clinical trial will be randomly placed
in one of six study groups to be vaccinated over 43 months. One
group will receive the licensed regimen of eight vaccinations under
the skin. Another group will receive eight vaccinations of a saltwater
placebo. The remaining groups will be vaccinated in the muscle rather
than under the skin and will receive fewer vaccine doses.
Blood will be drawn following each vaccination to evaluate the
protective immune response. No live anthrax bacteria will be used
in the study; the vaccine does not contain the whole anthrax germ
and cannot cause an anthrax infection.
A total of 1,560 volunteers nationwide will be enrolled in the
clinical trial, and Emory will enroll approximately 200 of these
volunteers. Partici-pants must be 1861 years of age and must
not have any major health problems. The study will require 25 visits
over 43 months. At each visit, participants will either receive
an injection, have an investigator look at the injection site, or
have blood drawn. Participants will not know which study group they
are in until the end of the study. All laboratory tests will be
provided free, and participants will receive compensation for each
The anthrax vaccine has an excellent safety record,
Keyserling said. We hope this new study will simplify the
existing dosing and shot regimen for the vaccine and provide more
data to convince an anxious public that the vaccine is safe.
For more information, call Keyserlings research staff at