Corrections

APPLIED MATHEMATICS. For the article ‘‘Multiscale, resurgent epidemics in a hierarchical metapopulation model,’’ by Duncan J. Watts, Roby Muhamad, Daniel C. Medina, and Peter S. Dodds, which appeared in issue 32, August 9, 2005, of Proc. Natl. Acad. Sci. USA (102, 11157–11162; first published July 29, 2005; 10.1073 pnas.0501226102), on page 11159, the first sentence of the right column, ‘‘In contrast with the usual prediction of bimodal size distributions, recent work (35) has suggested that the sizes of epidemics in isolated communities, including Iceland, are ‘‘power law’’ distributed (P[ ] ), and that such epidemics might therefore be the result of self-organized criticality (36)’’ should read: ‘‘In contrast with the usual prediction of bimodal size distributions, recent work (35) has suggested that the sizes of epidemics in isolated communities are ‘‘power law’’ distributed (P[ ] ), and that such epidemics might therefore be the result of self-organized criticality (36).’’ Ref. 35 considered epidemic size distributions for the Faroe Islands, near Iceland, and for Reykjavik, the capital of Iceland, but not for Iceland itself. In addition, the authors note that the following acknowledgment was omitted from the article: ‘‘We are grateful to P. Haggett and A. D. Cliff for providing the Iceland data and to M. Lipsitch for providing Fig. 2C. This research is supported in part by the National Science Foundation (Grants SES-0094162 and SES-0339023), Office of Naval Research, McDonnell Foundation, and Legg Mason Funds.’’