Western countries are living in a state of terror, and we seem to be doing a better job than the terrorists of terrifying ourselves.
The current fear is that terrorists may spread smallpox among us, and it's one that is being taken very seriously in the USA where healthcare workers are lining up for inoculation.
We're frightened of smallpox because we don't know much about it, other than it is a dread and fatal disease.
But Thomas Mack, an American doctor who treated a smallpox outbreak in Pakistan in the late 1960s, has a very different view. The outbreak in Pakistan was quickly contained, not because of an intensive vaccination programme, but because smallpox is hard to catch, he says.
A victim is at his most contagious during the first week that a florid rash, and deep skin lesions, appear, and this happens around two to three weeks after initial infection.
Even then, the virus travels only a short distance from the victim to someone else. Scientists were able to grow the virus only from the patient's face and bedding. But attempts to do so from exhaled air all failed. This is because the virus is discharged, not from breath, but from saliva. Most infections in Pakistan happened at the bedside of a victim, says Dr Mack. Nobody caught smallpox while on a plane, train or bus, so lending credence to the idea that it is not an airborne disease.
Dr Mack estimates that even a very successful smallpox attack from terrorists will result in fewer than 20 cases, and 10 deaths, across the USA, whereas 800 people will die from complications from the vaccination.
Instead, education of the public about the disease, and its early warning signs, would be a far more effective strategy, says Dr Mack.
(Source: New England Journal of Medicine, 2003; 348: 460-3).