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How Anthrax Works

Vaccine and Treatment Research

The vaccine that was developed in the 1950s (licensed in 1970), is currently only given to military personnel, people who work directly with anthrax in research labs, and those who work with animals and animal by-products that may be infected with anthrax. The vaccine uses the anthrax protective antigen to make the body create immunity to the disease. It is created from a strain of anthrax that does not cause the disease, and doesn't use any live or dead whole bacteria. There is a separate vaccine for use in animals. (That vaccine can't be used in humans.)

The side effects of the anthrax vaccine include:

  • Mild local reactions at the site of the injection (like with many other vaccinations)
  • Occasional, moderate local reactions that include redness, swelling and tenderness, often at the site of the injection and extending up to 5 inches (13 cm) across the area
  • Large local reactions larger than 5 inches, including swelling of the forearm and at the injection site
  • Muscle aches, joint aches, headaches, rash, chills, fever, nausea, loss of appetite, and weakness for a few days after the vaccination (experienced in up to 35 percent of people who get the vaccine)
  • A severe allergic reaction (appears once in every 100,000 doses)
  • A severe reaction that requires hospitalization (appears once in every 200,000 doses)


Studies by R. John Collier and his colleagues at the Harvard Medical School have uncovered a possible therapy that can be used both as a vaccine and as a treatment for anthrax after the fact (particularly when antibiotics were not administered quickly enough).

This research was based on the previous findings by George Vande Woude and others at the National Cancer Institute in Frederick, MD, that identified the role of the protective antigen in allowing the lethal factor and the edema factor to enter the cell and begin wreaking havoc. Collier's research involved mutating the protective antigen to prevent this transfer. Experiments have suggested that even a single protective antigen mutant can disrupt the entire process. This treatment has worked in rats exposed to anthrax, but it is still not known how long after exposure the treatment could be given and still be effective in stopping the disease.

Because mutant protective antigen also appears to bring about an immune response (at least in rats), it has the potential to be a vaccine as well as a treatment. If successful, this approach could also be used for other diseases.

For more information on anthrax and related topics, check out the links on the next page.