In the US, the principal purchasers of the vaccine are the Department of Defense and Department of Health and Human Services. Ten million courses (60 million doses) of the vaccine have been purchased for the US Strategic National Stockpile in anticipation of the need for mass vaccinations owing to a future bio-terrorist anthrax attack. The product has attracted some controversy owing to alleged adverse events and questions as to whether it is effective against the inhalational form of anthrax.