
Pandemic (H1N1) 2009 influenza is different to the seasonal flu. While older people are generally considered vulnerable to seasonal flu, they appear to have had less infection with pandemic H1N1 2009 influenza.
However, older people with underlying chronic medical conditions can suffer a more severe illness when they get influenza and a more rapid deterioration, due to underlying disease, ageing of the immune system, immobility or debility.
Conditions that make people vulnerable to severe infection include: