Even if you aren’t old enough to remember it yourself, you have surely read about the nuclear preparedness campaigns of the 1950s. In the event of imminent attack, schoolchildren were told to "duck and cover," seeking shelter under their desks or in a drainage ditch. The whole idea has become such a subject of ridicule for pundits, who have determined through careful study that a first-grader’s desk cannot always be relied on to deflect a thermonuclear detonation.

What everyone seems to have forgotten—including political types who should know better—is that the "duck and cover" maneuver was intended to protect against flying glass, collapsing ceilings and prompt radiation far from the blast site. Hiding under a table can indeed save your life, whether the threat is a hurricane or a nuclear bomb. Just what should the nation have advised its children to do—stand up and take their chances?

Today’s threat is more complicated, and diving for cover isn’t an option. Nevertheless, there are some basic measures that we can take now to protect ourselves and our patients. The most obvious of these is immunization against smallpox.

Much has been written and said about the wisdom, or lack thereof, of reinoculating the population against a disease that, after all, is but one of many options available to the bioterrorist. The vaccinations themselves are not without risk, though serious adverse events are rare. I can’t say whether an individual should or should not be immunized. But there are special considerations that apply to the dental community, as we prepare for what is likely to be a large-scale immunization campaign.

Vaccination against smallpox is one of the earliest and greatest triumphs of scientific public health. George Washington, ever a paragon of leadership, had soldiers of the Continental Army vaccinated, but only after he underwent the frightening procedure himself. From this and other early initiatives, smallpox vaccination became accepted, then common, then virtually universal. The disease was on the run. By 1972, smallpox was declared eradicated, and vaccination was discontinued.

For the past three decades, the entire world has enjoyed "herd immunity" from this disease. The near-universal immunization that began in the last century essentially starved the virus of victims, driving it to extinction in the wild. With fewer and fewer infected carriers, the chance of contact eventually became vanishingly low. It gradually became less important that any individual be resistant to infection—the "herd" as a whole was resistant.

But the virus still exists. There are stockpiles of attenuated virus for immunization, and it is probable that several undesirable elements have supplies of the fully active virus that could be "weaponized." Governments are working to counter this grim possibility, and are just now beginning to spell out the "how" and "who" of a defensive vaccination program.

You are aware—though your patients may not be—that the smallpox vaccination is fundamentally different from most of their other immunizations in that it involves an attenuated live virus. In contrast to most other vaccines, which trigger the immune system directly, this one actually infects the patient with a virus (vaccinia) too feeble to cause a full-blown case of smallpox, but sufficient to provide immunity. It’s a direct outgrowth of Jenner’s 18th century observation that milkmaids, who often contracted a mild case of cowpox, seemed to be immune to smallpox. The process really hasn’t changed much since the days of George Washington.

Many of us can point to small scars on our upper arms, souvenirs of childhood vaccinations. You may also remember the healing wound, if not your own, then perhaps your younger sibling’s. What you know now is that the recipient of the vaccination was actually shedding active virus while the immune system did its work. With that in mind, let’s consider what it means to be a practicing dentist.

First of all, give careful thought to being inoculated or reinoculated yourself. Absent immune problems or unusual sensitivities, there is little reason to fear the procedure. And who knows, it may save your life.

This said, remember that for a period of two to four weeks, the vaccination site will be shedding live virus. You will pose a danger, however slight, of transmitting it to your patients. Inform them all, but be sure to reschedule any immunocompromised and other at-risk patients. (I take this precaution for immunosuppressed or immunocompromised patients when I have even a common cold.) Or you could schedule your vacation so as to shed virus on a nice beach somewhere. Or you could continue with business as usual and hope for the best.

Remember, too, that many of your patients will have been recently vaccinated, even if you have not been. The same precautions apply in reverse, particularly if you, the dentist, have problems with your immune system. Infection control and good communication are, as always, key. Solid information on the subject of smallpox can be found at "www.bt.cdc.gov/agent/smallpox/vaccination".

When we exchange one form of immunity for another—statistical for biological, one might say—there are some risks and unanticipated consequences. Infectious disease experts and public health officials are grappling with many of the issues. But it is ultimately up to us as individuals to make the important decisions that affect our patients and our families. Immunization against one disease may seem a feeble defense against the diverse weaponry of terror. But it’s a start.