Transmissibility of the H1N1 “swine flu” influenza strain causing the ongoing outbreak is substantially higher than that seen in seasonal influenza strains and may be comparable with that of pandemic influenza strains, according to an early analysis of the virus by an international team of scientists participating in the World Health Organization's Rapid Pandemic Assessment Collaboration (Fraser C et al. Science. doi:10.1126/science.1176062 [published online ahead of print May 11, 2009]).
Stephenson J. H1N1 Influenza Analysis. JAMA. 2009;301(23):2432. doi:10.1001/jama.2009.818