Prior to the influenza A(H1N1) pandemic of 2009-10, few data were available with regard to virus survival on different household surfaces. With a few notable exceptions [10, 11] , the majority of studies had been carried out based on RT-PCR to detect the presence of the genome [20] [21] [22] ; these shed no light on the presence or absence of viable virus. In this study we sought to provide contemporary data about virus survival on a wider range of materials found in or on household surfaces than previously described in the literature; these exemplars were chosen after discussion with UK pandemic policy makers. However, one limitation is that our study was confined to H1N1 influenza A viruses (PR8 and the 2009 pandemic virus) due to resource issues. However, we know of no evidence to suggest there are substantial differences in survival between human influenza viruses. Moreover, when we compared the survival of PR8 virus with two seasonal isolates of influenza A (A/Solomon Islands/12/5/08 (H1N1) and influenza A/Brisbane/12/5/08 (H3N2), obtained from Professor Alan Hay of the National Institute of Medical Research, Mill Hill), we saw no significant differences, with all three viruses losing plaque titre on a plastic surface with a t1/2 of around 90 minutes (data not shown). We therefore think it is reasonable to generalise from the findings here to other human strains of influenza A. Further studies, especially of influenza B are warranted however. We applied concentrations of virus (,1610 6 TCID 50 ), which were within the range of those reported in the respiratory secretions of naturally infected individuals [5, 10] . In addition, we suspended virus in 1% bovine serum albumin (BSA), reflecting our (unpublished) finding that BSA improved virus survival, and similar findings from Thomas et al [11] using mucus obtained from children. Our experiments were conducted within a narrow range of humidity and temperature conditions consistent with normal human indoor living conditions in temperate zones, and all survival assays were performed in duplicate and where possible triplicate. We used plaque assay techniques and immunofluorescence techniques for PR8 and pandemic viruses, respectively. The differing methodologies used to detect the two strains of H1N1 virus (lower titre inoculum of the pandemic AH04 virus but higher sensitivity detection method) make it difficult to directly compare the survival of the two strains, but we see little to suggest any major difference.