Editor's Summary
17 November 2005
Coughs and sneezes...
From Typhoid Mary to SARS, it has long been known that some people spread disease more than others. But for diseases transmitted via casual contact, contagiousness arises from a plethora of social and physiological factors, so epidemiologists have tended to rely on population averages to assess a disease's potential to spread. A new analysis of outbreak data shows that individual differences in infectiousness exert powerful influences on the epidemiology of ten deadly diseases. SARS and measles (and perhaps avian influenza) show strong tendencies towards 'superspreading events' that can ignite explosive epidemics — but this same volatility makes outbreaks more likely to fizzle out. Smallpox and pneumonic plague, two potential bioterrorism agents, show steadier growth but still differ markedly from the traditional average-based view. These findings are relevant to how emerging diseases are detected and controlled.
News and Views: Epidemiology: Dimensions of superspreading
Analyses of contact-tracing data on the spread of infectious disease, combined with mathematical models, show that control measures require better knowledge of variability in individual infectiousness.
Alison P. Galvani and Robert M. May
doi:10.1038/438293a
Letter: Superspreading and the effect of individual variation on disease emergence
J. O. Lloyd-Smith, S. J. Schreiber, P. E. Kopp and W. M. Getz
doi:10.1038/nature04153
First paragraph | Full Text | PDF (375K) | Supplementary information
