On request of the authors, the following changes were made on 14 November 2012 in the article 'Hospitalisation associated with the 2009 H1N1 pandemic and seasonal influenza in Hong Kong, 2005 to 2010' by L Yang et al., published on 8 November 2012:

1. The first three sentences of the second paragraph of the Methods section were replaced by:

We obtained the weekly numbers of detected influenza viruses reported by the Public Health Laboratory Centre, Hong Kong from the weekly report ‘Flu Express’ available on the website of the Centre for Health Protection at the Department of Health (DH) (http://www.chp.gov.hk/en/guideline1_year/441/304.html). The numbers of specimens were estimated from the summary tables of the Centre’s Sentinel Surveillance website (http://www.chp.gov.hk/en/sentinel/26/44/292.html). The respiratory specimens were collected from hospitalised patients and outpatients from the public and private healthcare sectors in Hong Kong and were tested by viral culture and subtyped by haemagglutination inhibition tests. As the online reports for other respiratory viruses were not publicly available from the DH during the study period, we also obtained the virology surveillance data for respiratory syncytial virus (RSV), adenovirus and parainfluenza viruses from the microbiology laboratory of Queen Mary Hospital.

     2.     A footnote was added to Table 1: The annual figures in this Table were obtained by cumulating weekly data from week 1 to 52 (or 53) of each year.