AVA and AVP – Anthrax Vaccine Type | Usage | Precautions
- Anthrax is a serious condition caused by Bacillus anthracis, a spore forming gram-positive rod.
- It manifests in three forms: cutaneous, respiratory and gastrointestinal.
- It is mainly a disease of zoonotic origin – transmitted to humans either via direct contact with the bacteria from animal sources or spores.
- AVA and AVP: sub-unit (non-cellular) vaccine containing three antigens: Protective antigen (the main antigen), Edema factor, and Lethal factor.
- Live attenuated vaccines: mainly used in veterinary care.
- Anthrax Vaccine Adsorbed (AVA): The only vaccine licensed by FDA for use in the US. It is used intra-muscularly but can be used subcutaneously as well.
- Anthrax Vaccine Precipitated (AVP): used in the UK, given by intramuscular route.
- Others: Various other vaccines have been used historically in some countries like Russia, and some new ones are undergoing trails.
- Routine Use:
Anthrax vaccine is not used routinely. It is recommended for certain people who are at risk of exposure to B.anthracis, or unvaccinated persons who have been exposed to anthrax in some situations.
- Pre-exposure prophylaxis:
This is considered for certain people aged 18-65 years including:
- Certain laboratory or remediation workers
- Some people handling animals or animal products
- Some military personnel.
A 5-dose schedule is currently practiced, given as: 0, 4 weeks, 6, 12, and 18 months. An annual booster dose for those who continue to be at risk.
- Post-exposure prophylaxis: Following suspected or confirmed exposure to B. anthracis, a three-dose post exposure course is recommended as: First dose given as soon as possible, followed by two doses at 2 and 4 weeks intervals, given subcutaneously.Antimicrobial therapy as per local recommendations is to be used along with the vaccine.
- Patients who had severe allergic reaction to previous dose of the vaccine, or who are severely allergic to any component of the vaccine, including latex.
- Acutely ill people may be advised to delay vaccination until they are well again.
- Should be used in pregnancy only if benefits outweigh potential risk to the fetus.