About Anthrax Vaccine
An attenuated live animal vaccine (Sterne’s Vaccine) was developed in 1935 that is still employed and derivatives of this strain account for almost all veterinary anthrax vaccines used in the world today.
For human use, three vaccines are available, acellular (USA, UK) and live spore (Russia) vaccines.
The Russian vaccine is a live attenuated, unencapsulated spore, given either by scarification or subcutaneously. It is claimed to be reasonably well tolerated and showed some degree of protective efficacy against cutaneous anthrax in clinical field trials. The efficacy of the live Russian vaccine was reported to have been greater than that of either of the killed British or US anthrax vaccines (AVP and AVA, respectively). Today both Russia and China use live attenuated strains for their human vaccines. These vaccines may be given by aerosol, scarification, or subcutaneous injection. A Georgian/Russian live anthrax spore vaccine (called STI) is also available.
The British vaccine, sometimes called Anthrax Vaccine Precipitated (AVP), became available for human use in 1954. It is a cell-free vaccine in distinction to the live-cell Pasteur-style vaccine previously used for veterinary purposes. It is now manufactured by Porton Biopharma Ltd, a Company owned by the UK Department of Health. The active ingredient is a sterile filtrate of an alum-precipitated anthrax antigen from the Sterne strain in a solution for injection.
The American vaccine is called Anthrax Vaccine Adsorbed (AVA) or BioTharax. This vaccine is produced from culture filtrates of an avirulent, nonencapsulated mutant of the B. anthracis Vollum. No living organisms are present in this vaccine which results in protective immunity after 3 to 6 doses. AVA is the only FDA-licensed human anthrax vaccine in the United States and is produced by Emergent BioSolutions. When there were numerous substantive challenges regarding the vaccine and its safety, the FDA, after reviewing extensive scientific evidence, determined in 2005 that AVA is safe and effective as licensed for the prevention of anthrax, regardless of the route of exposure. BioThrax is only available for people 18 through 65 years old at increased risk of exposure to anthrax. Other types of anthrax vaccine are being developed in Israel and South Korea, and perhaps other countries.
Schedule
British AVP Vaccine:
The vaccine is given by intramuscular injection and the primary course of four single injections (3 injections 3 weeks apart, followed by a 6-month dose) is followed by a single booster dose given once a year.
US AVA Vaccine (BioThrax):
Five doses, over a period of 18 months, with a booster dose each year thereafter for those that continue to be at increased risk of exposure since the duration of immunity is not well known. It is also given, in combination with antibiotics, as a three-dose primary series after exposure. Although the vaccine is effective in protecting against anthrax, it does not prevent all cases. One study showed that the anthrax vaccine protects about 9 people out of every 10 vaccinated prior to exposure to the bacteria.
Side Effects
These vaccines are generally well tolerated and any side effects are usually mild and last only a few days. Reactions at the site of injection include redness, swelling, soreness or tenderness, a lump or bruise, itching, muscle aches or temporary limitation of movement in the arm where the shot was given, headache and feeling tired.
