Recommended post-exposure treatment of anthrax exposure victims currently includes antibiotics, human anthrax immunoglobulin, monoclonal antitoxin treatment and vaccination.
Vaccination
While there is a vaccine licensed to prevent anthrax, it is not typically available to the general public. Also, it is only approved for use before exposure and not after. It takes a number of months and multiple injections to obtain immunity for anthrax. Therefore, it is not the most suitable treatment after anthrax exposure. However, in case of an anthrax incident, the CDC advises that anthrax vaccine be given to people who have been exposed to help prevent disease. This would be allowed under a special emergency use protocol.
Antibiotics treatment
The antibiotics ciprofloxacin or doxycycline in combination with at least one more antibiotic agent are generally recommended as the first line treatment against anthrax exposure. However, there are serious liabilities with relying solely upon antibiotics. The emergence of antibiotic resistant strains can render them less effective or totally ineffective. In addition, even for antibiotics susceptible strains, treatment will have to be started almost immediately after exposure to be successful. Given the nature of bioterrorism, this may not be possible in most cases. In addition, as antibiotics do not tackle the problem of the lethal toxin produced by B. anthracis, many people could still die irrespective of the use of antibiotics. Once lethal toxin production has reached critical threshold, death occurs even if bloodstream sterility is achieved with antibiotics.
Anthrax Immunoglobulin
Passive immunization is a preferred solution to counter toxemia and therefore the use of anthrax immune globulin (AIG) is advocated. However, while the use of AIG offers a number of advantages such as limited adverse reactions, prolonged serum half-life and the targeting of multiple epitopes, it does suffer from the continued dependency on vaccinated blood donors and the need to be maintained, constantly renewed and tested. There will be batch-to-batch variation in specific activity, rendering efficacy more or less unpredictable, and as every batch undergoes extensive quality control partly to exclude the presence of pathogens, it is a costly approach. Also, it is questionable whether enough material can be raised to treat everyone if large numbers of individuals have likely been exposed in the event of an attack or accidental release.
Human monoclonal antibodies as medical countermeasures for anthrax
Human monoclonal antibodies (humAbs) are ideal candidates for the treatment of individuals exposed to a BW/BT agent. The advantage of human monoclonal antibodies is that they are not subject to concerns regarding potential transmission of pathogens, and that they have a longer half-life and lower immunogenicity than antibodies of xenogenic origin. In terms of efficacy, they will confer immediate protection, are effective pre and post exposure, and are also effective against strains genetically engineered to be resistant to multiple antibiotics. Treatment can effectively be limited to only those who have been exposed, are suspected to have been exposed, or are at risk of becoming exposed to an agent. In addition, also those with a weakened immune system will be helped with antibody treatment. Such exposure-guided treatment avoids the need for costly mass vaccination programs and avoids the health risks associated with large-scale prophylactic vaccination.