A contagious journey within a culture of complacency: the smallpox scare of 1962 in New York and Toronto.

In 1962 smallpox was perceived to be an ancient disease that was no longer a threat to public health in North America. This state of complacency was shattered, however, by the journey of a 14-year-old boy who entered the United States on a flight from Brazil and who then continued on into his native Canada. This trip led to an investigation and re-examination of immigration health procedures as well as a discovery of the general population's low level of smallpox immunity. The smallpox incursion was fought by the use of a thorough but troubling system of ring vaccination that left a good deal to pure luck. Many of the issues that grew out of this 1962 experience were subsequently resuscitated during the 21st century's fears concerning the use of biological weapons by potential terrorist groups.