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Last Updated

08 Nov 2002

Source: Pentagram, November 8, 2002.

Study to lower number of anthrax shots

Walter Reed Army Institute of Reasearch looks to reduce side effects of medication

by Karen Fleming-Michael, American Forces Press Service

A  study to decrease the required number of Anthrax shots and its accompanied side effects is being conducted at the Walter Reed Army Institute of Research.

"We want to use our stores of vaccine wisely and we want to immunize people effectively and minimize effects," said Col. Janiine Babcock, principal investigator for the study. The study's goals are twofold.

The first is proving the anthrax vaccine, manufactured by BioPort Corp in Lansing, Mich., is still effective when subjects are given fewer doses than the normal regimen of six shots -- one, two and four weeks and then at six, 12 and 18 months, with annual boosters.

"The [current vaccination] schedule is extremely cumbersome," Babcock said.

Decreasing the number of doses will also increase patient acceptance, she said. "If you have your choice between six shots and three, we'd all pick three."

The second goal is to change the way the shots are given, which should reduce the side effects of redness, tenderness, swelling and discomfort sometimes associated with the vaccine. Currently, the shot is given subcutaneously, which means the needle is inserted just between the skin and muscle.

"When you give vaccines subcutaneously, they work very well stimulating the immune system in a very powerful way, but they can cause more local side effects," Babcock said.

Serious reactions remain statistically rare. However, of the 2,120,594 doses given to 528,015 service members, 11 people reacted severe enough to result in hospitalizations that were "certainly or probably caused" by the vaccine, according to a May 2002 Anthrax Vaccine Expert Committee report.

By the mid-1970s, most vaccines were given by intramuscular injections because they produce fewer side effects and they are easier to administer. The anthrax vaccine, which was developed in the 1950s and 1960s and licensed in 1970, remained a subcutaneous injection because only a few hundred people, mostly veterinarians, received it each year, and no one approached the Food and Drug Administration about changing it.

"When we now vaccinate hundreds of thousands of people, we want to use it as well as we can," said Col. Alan Magill, deputy division director for Communicable Diseases and Immunology and also a study associate investigator.

The study hopes to show intramuscular shots are the best way to deliver the vaccine.

The clinical study is based on preliminary results Dr. Phil Pittman found in a study conducted at the U.S. Army Medical Research Institute of Infectious Diseases at Fort Detrick from 1996 to 1998.

The study, funded by Congress, has three parts: Part A is a human study, Part B is a primate study and Part C is a basic science study.

The research institute is participating in Part A, which involves testing the change from subcutaneous to intramuscular injection and decreasing the number of doses. Part B will test the changed regimens against an aerosol challenge in primates to show whether they are protected from getting anthrax.

Part C will go a long way in helping develop new generations of the anthrax vaccine. Researchers will examine blood samples from people and primates taken at the same times, such as before a dose and after a dose, to find the key things in the immune system that predict protection.