Biohazard

Repeated vaccinations has been known to trigger or aggravate allergies. Thirty minutes after I received my last vaccination against anthrax in 1987, my face became swollen, and I developed a rash and had trouble breathing. I took Dimidrol, a powerful anti-allergy medication available in Russia (though not in the United States) and felt better again in a few hours. For the next ten days I received intravenous preparations at a hospital — a form of allergy treatment we called desensibilization therapy. Several colleagues had been forbidden from anthrax work after similar reactions. I knew this was a sign that I was genetically susceptible to large quantities of specific foreign proteins, and that my immune system had been stretched to its limit. I received my first anthrax vaccination in 1979 and began a course of annual vaccinations in 1982. I was also vaccinated against smallpox once, twice against tularemia, and four times against plague. The chronic allergies I have suffered throughout my adult life are a direct consequence of repeated exposure to live vaccines, and to other biological substances I worked with.

Vaccines provide excellent protection against specific diseases, but the characteristic that makes them so effective — that specificity — is also the source of their limitations. Smallpox antibodies offer no protection against plague. A typhoid vaccine will not lower the risk of measles. Combined vaccines are possible, such as the diphtheria-pertussis-tetanus shot given to children, but most of these go straight to the metabolism of specific organisms. A vaccine works against a single pathogen, or occasionally several similar ones, but an all-purpose antidote does not exist.

The use of vaccines for biodefense makes sense when we know what agent is likely to be used and when we can identify a specific target population — troops, for instance, within range of a known arsenal. But the protection they confer must be measured against a shifting threat. An adversary who knows that his opponents' troops have been inoculated against anthrax can switch his battle plans to smallpox or plague — or to an agent for which no vaccine exists. We can vaccinate our soldiers against a minimal combination of the most likely threats, but we will still not know whether an opponent has developed a weapon virulent enough to overcome existing antidotes.

Despite American efforts and expenditures, vaccines have limited value for the protection of civilians. Who would be deemed vulnerable? And which agents should they be protected against? A crash program to increase the available doses of smallpox vaccine in the United States (currently seven million) might deter a country or a terrorist group from launching a smallpox attack, but there are plenty of other options. And who would get those seven million doses if several cities are attacked at once? The city of New York alone has a population of over seven million. Will each city have its own stockpile?

I am not suggesting we should drop vaccines from our biodefense plan, only that we should keep their effectiveness in perspective. Even if we could afford the expensive and lengthy process of development, testing, and approval currently required for the introduction of new vaccines in the United States and most Western countries, the continued advances in weapons-making knowledge will always put us a step behind.

Over the past two decades, scientists have vastly expanded our understanding of how the immune system works. This knowledge can be exploited to provide a new form of medical defense against biological agents. In the simplest terms, the immune system works by distinguishing our cells from the alien microorganisms that invade our bodies every day. We have at our disposal a network of agents programmed to make such distinctions and report on their findings. New antibodies are continuously being formed to recognize specific threats and eliminate them before they cause damage. These antibodies and the agents that code for their formation arc endowed with what we call memory — the ability to recognize a previous invader. This subcellular capacity lies at the heart of the success of vaccines. For years immunologists focused exclusively on vaccines and the antibodies they produced — the most visible elements of specific immunity — ignoring the processes that have come to be grouped together under the general rubric of nonspecific immunity.