Anthrax - The Threat, The Disease: Questions and Answers for Soldiers


1. Why is anthrax vaccination needed?

Anthrax vaccination is needed because the threat from anthrax weapons is real and lethal. The Chairman of the Joint Chiefs of Staff named anthrax as the #1 biological threat. The current world threat environment and the unpredictable nature of terrorism make it prudent to include biological warfare defense as part of our force protection planning. Weapons inspectors discovered during the Gulf War that Saddam Hussein maintained an anthrax arsenal sufficient to kill every man, woman and child on the face of the earth.

By 1992, U.S. intelligence sources recognized that the former Soviet Union maintained a capability that dwarfed Iraq's. Inhalation anthrax following a biological warfare attack is almost invariably lethal to those who become infected, if not treated quickly. Even with prompt treatment, after symptoms develop the likelihood of death is 80%. Bio-weapon attacks may not be detected until large numbers of people become ill. The anthrax vaccination program is the most effective round-the-clock method of countering the threat of anthrax-weapons.

2. Has any country ever used anthrax as a weapon?

There is some evidence that anthrax was used as a biological weapon (BW) on a limited basis by the Japanese in China during World War II (Christopher GW, et al. Biological warfare: A historical perspective. JAMA 1997;278(Aug 6):412-17). Since then, several countries are believed to have incorporated anthrax spores into biological weapons. Intelligence analysts believe that at least seven potential adversaries have an offensive BW capability to deliver anthrax -- twice the number of countries when the 1972 Convention on the Prohibition of the Development, Production and Stockpiling of Bacteriological (Biological) and Toxin Weapons and on Their Construction (commonly called the Biological Weapons Convention) took effect. The Biological Weapons Convention was designed to prohibit such activity.

Iraq admitted to the United Nations in 1995 that it loaded anthrax spores into warheads during the Gulf War. In the post-cold war era, the former Soviet Union admitted to having enough anthrax on hand to kill every person on the planet several times over. The accidental aerosolized release of anthrax spores from a military microbiology facility in Sverdlovsk in the former Soviet Union in 1979 resulted in at least 79 cases of anthrax infection and 68 human deaths and demonstrated the lethal potential of anthrax aerosols. Members of Aum Shinrikyo, the group responsible for the 1995 Tokyo sarin attack, reportedly experimented with biological agents in Japan before resorting to chemical agents.

A lengthy article in the May 26, 1998, edition of the New York Times reported that members of Aum Shinrikyo released anthrax spores and botulinum toxin in Tokyo, Yokohama, and Yokosuka in 1990, targeting Japanese government and U.S. Navy facilities. Fortunately, no one was injured in these events.

3. How are biological agents deployed?

Biological agents can be dispersed in many ways, ranging from simple spray devices to ballistic missiles. Biological agents are often hard to detect. Symptoms are delayed. And without preventive medical efforts, such as vaccination, the results can be devastating and widespread.

A 1993 report by the U.S. Congressional Office of Technology Assessment estimated that between 130,000 and 3 million deaths could follow the aerosolized release of 100 kg of anthrax spores upwind of the Washington, DC, area -- truly a weapon of mass destruction. An anthrax aerosol would be odorless, invisible, and capable of traveling many miles.

4. Has the threat of biological warfare changed?

The threat of biological warfare has been a risk to U.S. forces for many years. DoD analysts maintain an updated evaluation of the level of threat, adjusting the information as necessary to reflect the risk to U.S. operations. Assessment of the potential offensive biological threat facing American service men and women indicate it is necessary to have a robust biological defense program today.

The threat is real and consequences are grave -- former Director of the CIA James Woolsey referred to it as the single most dangerous threat to our national security in the foreseeable future.

5. Since we have known about the anthrax threat for years, why implement this program now?

During the 1990s, countries hostile to the United States increased their capability to weaponize and deliver anthrax. Terrorist organizations sympathetic to our potential adversaries have become more active. Additionally, advancement in weapon delivery systems increased the capability of many countries that previously did not possess the technology to pose a serious threat. These factors led to the decision to protect the force with anthrax vaccine.

6. Who will receive the anthrax vaccination?

Effective 30 November 2000, only personnel assigned or deployed on the ground in Southwest Asia (Kuwait, Saudi Arabia, Bahrain, Jordan, Qatar, Oman, United Arab Emirates, Yemen, and Israel) for more than 30 consecutive days and those personnel afloat in the Persian Gulf who have the potential of being committed ashore. Anthrax vaccinations of other personnel will resume when adequate FDA-released supplies of vaccine become available.

7. Who is at greater risk from a biological attack? Soldiers? Sailors? Airmen? Marines? Front line? Rear area? Logistical units?

Anthrax weapons have the potential to cover wide areas of a battlefield. It is difficult to determine who would be at a greater risk from a biological threat. The entire force needs to be protected.

8. What preparations have been made to respond to an anthrax release in a high-threat area?

The status of sufficient personnel and materiel, both medical and other logistics, is continually reassessed by the commanders in chief (CINCs) for their geographical areas of responsibility. Specific details of U.S. capability in supporting war plans are classified. There is no theater of war currently, but the status of personnel, medical materiel, evacuation equipment, and hospitalization assets in all geographical areas of responsibility are maintained at a high state of readiness.

U.S. forces are prepared to address a wide range of possible contingencies and crises in the region. All military personnel are trained to respond immediately by assuming a mission-oriented protective posture (MOPP) commensurate with the risk, and provide first aid to injured personnel. Deployed medical personnel are trained to respond to symptoms of biological disease and chemical casualties that may be encountered in modern warfare; provide or direct patient decontamination activities and render resuscitative or definitive medical care.

9. Has anthrax vaccine ever been used in the past? How many times? By the military?

Yes, anthrax vaccine has been administered to people at risk (veterinarians, laboratory workers, and some civilians working with livestock) for several decades. The manufacturer and FDA report that about 68,000 doses of anthrax vaccine were distributed between 1974 and 1989.

Anthrax vaccine has been purchased by the Army since its approval by the FDA in 1970, for use by about 1,500 at-risk laboratory workers. Anthrax vaccine was administered during the Gulf War to about 150,000 Service Members, to protect U.S. forces against Iraq's biological weapons. The military currently vaccinates people working in at-risk jobs, about 3,000 personnel assigned to special operations units, the Army Technical Escort Unit, and the Marine Chemical-Biological Initial Response Force (C-BIRF), plus Service Members deploying to high-threat areas.

10. If we vaccinate against anthrax, couldn't our adversaries just switch to a different bio-weapon?

If the DoD anthrax vaccination program causes adversaries to switch to a different weapon, it can be considered a success. Other bio-weapons are less stable, less predictable, or less effective than anthrax weapons.

11. Are vaccines being developed for other biological agents?

Yes. As potential biological warfare threats are identified, DoD is working with the FDA to determine appropriate protection mechanisms. Vaccines are being developed, whenever appropriate, for all validated biological threat agents.


1. What is anthrax?

Anthrax is a rapidly progressing acute infection caused by spore-forming bacteria called Bacillus anthracis. Anthrax most commonly occurs in warm-blooded animals, especially goats, cattle, and sheep, but it can also infect humans.

Anthrax spores can be easily produced in a dry form for biological weapons. Spores can survive many years in adverse conditions and still remain capable of causing disease. When inhaled by humans, these spores cause respiratory failure, leading to death within a week. Anthrax can make an excellent weapon of mass destruction. The spores may be used as a weapon in a variety of delivery systems. They can be produced in large quantities without sophisticated equipment. All it takes is a single breath of aerosolized anthrax to inhale enough spores to cause the disease. Then, if serious symptoms occur, it kills 99% of unprotected people. Even if a person with symptoms receives antibiotics, the death rate is still about 80%. Anthrax spores are odorless, colorless, and tasteless.

2. Who gets infected with anthrax?

Animals and people can get anthrax disease. Anthrax is most commonly found in agricultural regions where goats, sheep, cattle or other plant-eating animals have not been vaccinated. When anthrax infects humans, it is usually due to an occupational exposure to infected animals or their products, especially hides, hair, wool, bones or bone products. Less commonly, humans can be infected by ingesting undercooked, contaminated meat.

3. Where is anthrax usually found?

Anthrax is found around the globe. It is more often a risk in countries that do not vaccinate their livestock, or that have substandard or ineffective public-health programs.

4. How is anthrax transmitted?

There are three forms of anthrax disease, varying by the route of infection. People can get anthrax through a break in the skin (cutaneous anthrax), by eating inadequately cooked contaminated meat (gastrointestinal anthrax), or by inhaling bacteria or spores. Inhaled anthrax does not typically spread from person to person. Because anthrax spores can live in the soil for many years, animals can get anthrax by grazing or drinking water in contaminated areas. Weaponized anthrax could be used against people in almost any location, and in many different ways. The greatest threat with the most deadly consequences comes from inhaled anthrax.

5. Can people spread anthrax to each other?

Direct person-to-person spread of inhalation anthrax is "very rare," according to the American Public Health Association's Control of Communicable Diseases Manual. Presumably, person-to-person spread would require contact with contaminated skin lesions.

6. Can anthrax be transmitted by insects?

One report suggested that black flies may have transmitted anthrax from animals to humans, where there was a large outbreak in the animal population. Insects are not a major factor in the spread of anthrax.

7. How is anthrax diagnosed?

Anthrax is diagnosed by isolating the bacteria, Bacillus anthracis, from the blood, skin, or cerebral spinal fluid, or by measuring specific antibodies in the blood of suspected cases. Generally, diagnosis by antibodies is done weeks or months after the infection occurs, too late to aid in treatment. The best protection is vaccination before exposure, combined with the appropriate Mission-Oriented Protective Posture (MOPP), including protective clothing and detection equipment.

8. Why vaccinate at all? Why not treat with antibiotics after exposure?

Immunization is the safest, most effective way to provide protection against anthrax. The incubation period for inhalation anthrax is 1 to 6 days. The initial symptoms of inhalation anthrax are so nonspecific that diagnosis is very difficult. Without antibiotics, inhaled anthrax is 99% fatal. After serious symptoms have occurred in unvaccinated people, despite intensive care treatment and antibiotics, death rates still exceed 80%.

Therefore, antibiotic treatment must be started at the earliest sign of disease. Antibiotics may protect people without symptoms after a known exposure to aerosolized anthrax spores, but may be ineffective following a large dose, unrecognized exposures, or exposures recognized only after symptoms appear. Anthrax spores are odorless, colorless, and tasteless. The fact that anthrax is difficult to diagnose until terminal symptoms are present and that the mortality rate is 80% even with antibiotic therapy once terminal symptoms begin, make using a safe and effective vaccine the only reasonable option to prevent inhalation anthrax.

Source: Department of Defense, Anthrax Vaccine Immunization Program (AVIP) Agency, Office of the Army Surgeon General, July 2001