News Release

Monday, August 31, 2009

Studies in Animals Suggest 2009 H1N1 Virus May Have Biological Advantage Over Seasonal Influenza Viruses

Preliminary findings in ferrets suggest that the novel 2009 H1N1 influenza virus may outcompete human seasonal influenza viruses, researchers say. Tests in animals showed that levels of the 2009 H1N1 virus rose more quickly than levels of the seasonal virus strains, and the new virus caused more severe disease. In line with previous findings by other research groups, the University of Maryland researchers also observed that the novel H1N1 virus was transmitted more easily from infected to uninfected ferrets than either of the two seasonal influenza viruses.

The investigators' findings are posted on PLoS Currents: Influenza, a Web site for rapid communication of new scientific data on influenza. Submissions to PLoS Currents: Influenza are screened by a panel of leading influenza experts prior to posting but do not undergo formal peer review. The new research may be submitted later for peer review and eventual publication in scientific journals.

This research was supported in part through the NIAID Centers of Excellence for Influenza Research and Surveillance (CEIRS) program.

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D Perez et al. Fitness of pandemic H1N1 and seasonal influenza A viruses during co-infection. PLoS Currents: Influenza. Posted Aug. 25, 2009. RRN1011. Available at:

Additional information about research in Dr. Perez's laboratory is at: