Ring Vaccination Best Strategy for Smallpox Outbreak
Mathematical model shows isolation and vaccination of close contacts is best defense
TUESDAY, Aug. 8 (HealthDay News) -- The best strategy to control an outbreak of smallpox would be to quarantine affected individuals and immunize people they've had contact with, according to mathematical simulations of an outbreak in Great Britain published online Aug. 7 in the Proceedings of the National Academy of Sciences Early Edition.
Steven Riley, D.Phil., of the University of Hong Kong, and Neil M. Ferguson, D.Phil., of Imperial College London, used "an individual-based spatial model of smallpox transmission in Great Britain and census-derived journey-to-work data to accurately describe the spatiotemporal dynamics of an outbreak of smallpox in the community."
Using work travel routes to determine social networks likely to be paths of transmission in an outbreak, the investigators found that the best way to control smallpox spread would be to quarantine those who have signs of the disease, including a rash, and conduct ring vaccination -- a strategy where all people who could have had contact with the infected individual are vaccinated.
This strategy predicted a better outcome than just quarantine alone. Quarantine and regional mass vaccination, where all people living close to the affected individual are vaccinated, produced a slightly greater reduction in size and duration of the outbreak, but would not justify the higher number of vaccine doses required and their associated side effects, the authors report.