The NIH list on their Biodefense and Emerging Infectious Diseases website the NIAID Category A, B, and C Priority Pathogens. The Category A pathogens are those organisms/biological agents that pose the highest risk to national security and public health. I thought I would have a look at where we stand in terms of developing vaccines against some of these pathogen threats. Here are two of the priority pathogens – anthrax and Clostridium botulinum toxin:
Bacillus anthracis (anthrax)
Anthrax (caused by the bacterium Bacillus anthracis) usually affects livestock far more than humans. However, it still poses a threat when it comes to biological warfare. Current human vaccines against anthrax do exist and are given to military personnel and at-risk occupational groups. Licensed vaccines include "anthrax vaccine adsorbed" (AVA / BioThrax) in the US, and "anthrax vaccine precipitated" (AVP) in the UK. Recombinant protective antigen (PA)-based vaccines are in the pipeline, with the NIH announcing funding in 2010 to advance the development of two formulations of an anthrax vaccine that contain the rPA gene inserted into an adenovirus 4 vector. The funding will also cover the development of Emergent Biosolutions' BioThrax vaccine combined with an adjuvant. Reports in March that a US presidential ethics panel had given a tentative OK to testing an anthrax vaccine on children had us all asking whether such a trial would indeed be ethical.
Clostridium botulinum toxin (botulism)
Botulism is a severe neuroparalytic disease caused by toxins produced by several Clostridium species. There are seven serotypes (A-G) of Clostridium botulinum, four of which (A, B, E and F) cause human botulism cases. Up until October 2011, a pentavalent (ABCDE) botulinum toxoid (PBT) vaccine was administered to at-risk workers under an Investigational New Drug (IND) application held by the CDC. Recombinant subunit vaccines are in development, with DynPort's recombinant botulinum vaccine candidate, rBV A/B, completing Phase 2 clinical trials in January 2012. The vaccine was reportedly safe and well-tolerated, and elicited a strong immune response. "We are pleased with these results and are looking forward to Phase 3 clinical trials of this vaccine, to support the needs of the Department of Defense and the U.S. warfighter," said Dr. Robert V. House, president of DynPort.
Biodefense vaccine development was discussed at the World Vaccine Congress & Expo USA 2013 (Biodefense vaccines – overview, stockpiling and regulation). If you want to know more about strategy and innovation in vaccines, you might be interested in attending the World Vaccine Congress Asia 2013, 17-20 June 2013, Singapore.
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