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The only FDA-licensed human anthrax vaccine in the United States, Anthrax Vaccine Adsorbed (AVA, trade name BioThrax®), is produced by BioPort Corporation in Lansing, Michigan. The anthrax vaccine is produce from the cultured filtrates from a toxigenic, nonencapsulated strain known as V770-NP1-R. No living organisms are present in the vaccine. In the U.S., the principal purchasers of the vaccine are the Department of Defense and Department of Health and Human Services. The vaccine was purchased for the U.S. Strategic National Stockpile in 2005.

Anthrax is an acute infectious disease, caused by the spore-forming bacterium Bacillus anthracis, that most commonly occurs in wild and domestic mammals. Anthrax occurs in humans when they are exposed to infected animals or tissue from infected animals, or when they are directly exposed to B. anthracis. Depending on the route of infection, anthrax disease can occur in three forms: cutaneous, inhalational, and rarely, gastrointestinal.

The anthrax vaccine was originally licensed in 1970 by the U.S. National Institute Of Health (NIH) and in 1972 the Food and Drug Administration (FDA) took over responsibility for vaccine licensure and oversight. In 1997, the Clinton administration initiated the Anthrax Vaccine Immunization Program, under which active U.S. service personnel were to be immunized with the vaccine. Much controversy has surrounded the program since its inception, since vaccination was mandatory, and a perception developed that the anthrax vaccine was unsafe, causing sometimes serious side effects. Mandatory vaccination was halted due to an injunction which was put into place on October 27, 2004. The injunction did not question the safety and effectiveness of the anthrax vaccine or the immunization program in the Department of Defense, but rather centered on FDA procedural issues stating that additional public comment should have been sought before the FDA issued its Final Rule declaring the vaccine safe and effective, in December of 2003. On December 15, 2005, the FDA re-issued a Final Rule & Order on the license status of the anthrax vaccine. After reviewing extensive scientific evidence and carefully considering comments from the public, the FDA again determined that the vaccine is licensed for the prevention of anthrax, regardless of the route of exposure. At present vaccination is optional for active duty personnel. Approximately 50% of service men and women are voluntarily taking the vaccine according to a recent disclosure by the Department of Defense.

Vaccination schedule

Primary vaccination consists of three subcutaneous injections at zero, two, and four weeks, and three vaccinations at six, twelve, and eighteen months followed by annual boosters. For prolonged protection, annual boosters are recommended.

Adjuvant

The BioPort anthrax vaccine contains aluminium as an adjuvant. Each dose of the vaccine contains no more that 0.83 mg aluminium per 0.5mL dose. This is near the allowed upper limit of 0.85 mg/dose. The BioPort anthrax vaccine also contains 0.0025% benzethonium chloride as a preservative, and 0.0037% formaldehyde as a stabilizer. To maintain immunity, the manufacturer recommends an annual booster injection.

Controversy

The United States Centers for Disease Control (CDC) reported that from 1990 to 2000, more than 1,859,000 doses of anthrax vaccine were distributed in the United States. During that decade, 1,544 adverse events were reported to the Vaccine Adverse Event Reporting System (VAERS), 76 of these events (5%) were serious (results in death, hospitalization, or permanent disability or is life-threatening). Reports to VAERS are not necessarily events that have a cause and effect relationship, and the number of unreported adverse events caused by vaccines is unknown.

These figures are intrinsically misleading in as much as the VAERS system is a passive system, meaning that there is no notification process within the military to inform either troops or outprocessing servicemembers of it's existence, let alone instructions for completing the paperwork.

Although individuals have expressed health concerns after receiving anthrax vaccine, a congressionally directed study by the National Academy of Sciences concluded that anthrax vaccine is as safe as other vaccines. The Academy considered more than a dozen studies using various scientific designs, and heard personally from many concerned US military service members.

Concern has been raised that The Pentagon did not inform the United States Congress about more than 20,000 hospitalizations involving troops who had received the anthrax vaccine, because "hospitalizations merely followed vaccinations in time, without documented proof of a cause-and-effect relationship."

Bioterrorism preparedness

Demographic groups initially considered for preexposure vaccination, for bioterrorism preparedness, included emergency first responders, federal responders, medical practitioners, and private citizens. However, vaccination of these groups is not currently recommended.

Development of a new vaccine

While effective in protecting against anthrax, the licensed vaccine schedule is not very efficient, involving a cumbersome six dose injection series. Typically, six injections are given over a period of 18 months in order to induce a protective immune system response. The Centers for Disease Control and Prevention have undertaken a clinical trial to investigate more abbreviated vaccinations schedules for AVA.

Research is being done to develop and test new anthrax vaccines. One possible new type of vaccine would be administered by a skin patch rather than by injection.

References

  1. CDC.gov - 'Use of Anthrax Vaccine in the United States: Recommendations of the Advisory Committee on Immunization Practices', Centers for Disease Control
  2. FDA Anthrax Vaccine webpage
  3. "Molecular basis for improved anthrax vaccines" by R. N. Brey (2005) Advanced Drug Delivery Reviews volume 57, pages 1266-1292.
  4. "Aluminum salts in vaccines--US perspective" by N. W. Baylor, W. Egan and P. Richman (2002) Vaccine Volume 20 Suppl 3, pages S18-23.
  5. Detailed Safety Review of Anthrax Vaccine Adsorbed (PDF file) Compiled by the Military Vaccine (MILVAX) Agency (15 November 2005) United States Army Medical Command. (see also)
  6. Dailypress.com - 'An Incomplete Picture: Despite promises that hospitalizations after anthrax vaccinations would be reported, the Pentagon withheld data on more than 20,000 cases', Bob Evans (December 4, 2005)
  7. Taking the sting out of the anthrax vaccine by Laurie Goodman in the Journal of Clinical Investigation (2004) Volume 114 pages 868-869.

External links

Biological warfare | Vaccines

 

This article is licensed under the GNU Free Documentation License. It uses material from the "Anthrax vaccine".

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