The primary defense against the spread of smallpox or any other germ used in a bioterrorist attack should not involve a large-scale quarantine of potentially exposed individuals, as some emergency management personnel have proposed.

Instead, isolating exposed people, restricting mass transportation and informing the public about the nature of the outbreak and how they can minimize their risk of illness may more effectively prevent the spread of disease, according to a team of public health and biodefense experts.

Credible, authoritative public information is the key to managing both the disease effects of the outbreak and the terror effects on America. Implementation of quarantine, however, is not simple, will very likely be unsuccessful, and has significant unintended consequences.

Historical evidence suggests that quarantine can be harmful in some cases, leading to both the spread of disease from infected to noninfected persons sequestered together and to violence, if quarantined individuals resist the public health sanctions placed on them.

A further concern is bias, the authors note, which was seen during the quarantine instituted in 1900 after several Chinese residents of San Francisco were diagnosed with the plague. This quarantine, which included only Chinese households and businesses, was later judged unconstitutional because it unfairly promoted ethnic bias.

In addition, a large-scale quarantine would necessarily involve not only a prolonged separation of family members and possible stigmatization of the quarantined area, but also "potentially severe injury to the psyche of America, since for the first time we will be secondarily victimizing the victims of terrorism, rather than providing the usual outpouring of response and assistance that has inspired America and the world.

Thus, before calling for quarantine, officials should determine whether or not the action is warranted and feasible, and if its potential benefits will outweigh any adverse consequences.

In doing so, officials should consider whether the quarantine will effectively and significantly diminish the spread of disease, and whether there are enough resources to enforce and maintain the quarantine, including keeping areas of confinement safe and clean, and providing confined individuals with adequate food and medical care.

Lastly, decision-makers should determine the potential health risks to noninfected persons under quarantine, the consequences of noncompliance, and the economic effects of restricting commerce and transportation to and from the areas of confinement.

Viable alternatives to quarantine include isolation, whereby individuals known or suspected to be infected with a contagious disease are kept apart from others.

Other "more practically achievable" methods of disease containment, depending on the specific circumstances involved, may include restricting large gatherings, instituting short-term voluntary home curfews, promoting widespread use of disposable masks, and closing buses, trains and other systems of mass transportation.

JAMA December 5, 2001;286:2711-2717