Our data on the survival of the laboratory adapted PR8 virus indicated that viable virus was no longer recoverable in detectable amounts from 9 of 14 (64%) surfaces four hours after deposition; however, contrary to the findings of Bean et al., non-porous surfaces were not consistently more conducive to virus survival than porous ones [10] . Nevertheless, no test surfaces supported detectable virus survival beyond nine hours. Broadly similar outcomes in which infectivity tended to be lost after 4-9 hours were obtained with the recent pandemic isolate AH04. Overall, our results indicate that influenza virus does not remain viable in large quantities on most surfaces in indoor domestic conditions for more than a few hours. Our data are consistent with recent findings from a study of environmental deposition of pandemic H1N1 virus in the homes of infected patients, involving our laboratory, when almost 10% of tested surfaces yielded viable virus [15] . However, in this and similar studies in community settings where environmental samples are taken relatively infrequently and the infectious source remains present, it is not possible to establish the time elapsed since virus deposition [15, 23] .