The swine-origin new influenza variant A(H1N1) emerged in 2009 and changed the epidemiology of the 2009/2010 influenza season globally and at national level. Aims: The aim of the authors was to analyse the cases of two influenza seasons. Methods: The Medical and Health Sciences Centre of Debrecen University has 1690 beds with 85 000 patients admitted per year. The diagnosis of influenza was conducted using real-time polymerase chain reaction in the microbiological laboratories of the University and the National Epidemiological Centre, according to the recommendation of the World Health Organization. Results: The incidence of influenza was not higher than that observed in the previous season, but two high-risk patient groups were identified: pregnant women and patients with immunodeficiency (oncohematological and organ transplant patients). The influenza vaccine, which is free for high-risk groups and health care workers in Hungary, appeared to be effective for prevention, because in the 2010/2011 influenza season none of the 58 patients who were administered the vaccination developed influenza. Conclusion: It is an important task to protect oncohematological and organ transplant patients. Orv. Hetil., 2012, 153, 649–654.
