Vaccines against biologic agents: uses and developments.

Abstract

Although the Geneva protocol that prohibits the use of chemical and biologic weapons was ratified in 1925, many countries failed to accept this protocol: others stipulated retaliation, and some, like the United States, did not ratify the protocol for decades. This delay allowed the continued development of chemical and biologic agents. Members of the health care community are responsible for determining the best way to protect society from the potentially devastating effects of these biologic agents. Ideally,these diseases would be prevented from ever developing into systemic illnesses. In the past, vaccination has been a successful means of eradicating disease. Vaccines remain a hopeful therapy for the future, but time is short,and there are many obstacles.Information regarding bioterrorism agents and their treatments comes mainly from dated data or from in vitro or animal studies that may not apply to human treatment and disease. Additionally, the current threat of bioterrorism does not allow enough time for accurate, well-designed,controlled studies in humans before the release of investigational vaccines. Furthermore, some human studies would not be safe or ethical. Finally,many members of society suffer from illnesses that would put them at high risk to receive prophylactic vaccination. It is therefore naive to believe that vaccines would be the ultimate protection from these agents. In addition to vaccine development, there must be concurrent investigations into disease management and treatment. Even in instances in which vaccination is known to be an effective means of disease protection. biologic agents may be presented in a manner that renders vaccines ineffective. Virulent strains of organisms may be used, more than one organism may be used in tandem to increase virulence, and strains may be selected for antibiotic and vaccine resistance. Genetically engineered strains may use virulence factors other than those targeted in vaccines, and high concentrations of organisms may overcome vaccine protection. Finally,exposure may not be immediately noted until it is too late to vaccinate, as was the case with anthrax. Even in a case, such as smallpox, in which postexposure vaccination is possible, patients will still develop disease, and the health care system may be overwhelmed. The United States government has been defensively planning and researching the use of vaccines and chemoprophylaxis against any potential biologic agents since at least 1953, and resources are still lacking. There are inadequate stockpiles of vaccine to protect the entire population. The pharmaceutical industry also lacks a means of mass producing vaccines ina short timeframe. There is no policy in place for the use of vaccines that are yet unlicensed and experimental but may be the only therapy in the event ofa terrorist attack. Investigations into these solutions have been instituted only after the September 11, 2001, attacks heightened the awareness of terrorism. Although vaccination is an effective means of prophylaxis and a means of terminating epidemics or treating active disease, there is also resistance from the general public. In some instances there is a lack of acceptance of vaccines, or the risk of side effects is too great. In other cases, a questionable benefit does not justify the expense of mass vaccination. Because of this uncertainty, mass vaccination is deemed an impractical solution to the threat of bioterrorism. Extending vaccination with most vaccines to include all members of society who may be first responders in the event of an attack should be considered. In all instances, the benefit-to-risk must be weighed ratio when deciding how and when to offer preemptive prophylaxis to protect society from a real but unknown threat.