It is "virtually impossible" to accurately predict when a second wave of swine flu will hit the UK, the Government's chief medical officer has said.
Sir Liam Donaldson said the Government was expecting the number of cases to rise in the autumn but it was difficult to predict the timing with accuracy.
Some experts have said the swine flu cases will surge in September and October when schools and universities go back after the summer break.
Sir Liam's comments came as latest figures showed a continuing fall in the number of people newly diagnosed with swine flu, with an estimated 11,000 new cases in England last week. This was down on the 25,000 new cases estimated for the week before.
The data showed a drop in the number of cases across all age groups and in most parts of the country.
There are 263 patients being treated in hospital in England, of which 30 are in intensive care, down on the 371 (39 in intensive care) reported last week.
The number of deaths linked to the virus stands at 54, of whom 25 were in London. Last week, the number of confirmed deaths was 44. There have been five additional deaths in Scotland.
Sir Liam said just one in 10 people reporting flu-like symptoms to their GP or the National Pandemic Flu Service for England actually does have swine flu.
This is down on the figure of around one in four from several weeks ago, although Sir Liam said the drop was to be expected.
Monday tends to be the day of the week when the Pandemic Flu Service sees the highest levels of activity.
