The government's chief medical officer has reassured the public that even though the UK will see "many more cases" of swine flu in the weeks to come, most people will make a good recovery.
Responding to the news that the World Health Organization (WHO) has raised the alert level to phase five of six as the virus spreads, Professor Sir Liam Donaldson said he was "concerned but not alarmed".
"Most people who get flu, even a new strain of flu, will make a good recovery," Sir Liam told BBC Breakfast. "It's a nasty illness but it's short and they will recover.
"To put things in proportion, in any flu, even the seasonal flu, there are some deaths, often of elderly people and the very frail."
He said it was likely that many more cases would develop, but added that "on the whole most people make a good recovery from flu".
Three more people in Britain – including a 12-year-old girl – were confirmed as having the illness on Wednesday, and the WHO believes that a global outbreak is imminent.