I hear from parents almost everyday, wishing that vaccines were available to protect their children from smallpox or anthrax or other agents of bioterror. Routine smallpox vaccination was discontinued more than 20 years after the last smallpox case in the United States. Before September 11th, I heard from many parents who felt that vaccines such as those for polio or diphtheria should be discontinued because these once-dreaded infections had not been a major problem for many years. These illnesses felt like part of the distant past. We felt safe. But if these vaccines had been discontinued, perhaps diphtheria or paralytic polio would be in the headlines today: "Was the diphtheria nasal swab positive, or did the postal worker have cutaneous diphtheria?" Like anthrax, diphtheria is a gram-positive, toxin-producing bacillus that can be lethal. Unlike anthrax, diphtheria spreads easily from one person to another. Thankfully, most children are immune to diphtheria due to the 'routine' DTaP vaccination. For practical reasons, we can't immunize our children against smallpox or anthrax right now. Nevertheless, the standard childhood immunization schedule provides excellent protection against many of the biggest biological threats to our children.