Another 41 new cases of swine flu were confirmed in the UK today, pushing the total number above 400.
The Health Protection Agency announced 18 new cases in England, all in the West Midlands, while the Scottish Government confirmed 23 new cases north of the border.
The total number of people affected by H1N1 in the UK now stands at 404, with 313 in England, 88 in Scotland, two in Northern Ireland and one in Wales.
NHS West Midlands said 13 of the new cases were linked to Welford Primary School in Handsworth, Birmingham, which has been at the centre of the UK's largest outbreak.
A total of 96 people connected to the school, which reopened its doors on Monday, have now been diagnosed with the virus.
Another two children connected to the outbreak at Eton College were also confirmed with the virus.
The Berkshire school, which was attended by Princes William and Harry, said it will make a decision on Friday on whether to reopen as planned on Sunday.
At least six pupils have been confirmed with H1N1 at the school but it said today it was not in a position to confirm numbers of positive or possible cases.
The other cases involve adults from Coventry, Telford and Birmingham, who all recently returned from the US.
There are now 109 confirmed cases of swine flu in the West Midlands.
In Scotland a fourth victim has been admitted to intensive care, First Minister Alex Salmond said.
Yesterday it was revealed that a man and a woman are being treated in intensive care with swine flu, both in Royal Alexandra Hospital, Paisley.
The pair - a 45-year-old man from Paisley and a 38-year-old woman from Glasgow - are in a "critical but stable" condition.
The man is believed to be the first case in the UK to be admitted to intensive care without any underlying health problems.
Another man, aged 37, who already had health problems, was admitted to intensive care in Glasgow last week.
Meanwhile, the World Health Organisation has warned it is "getting closer" to declaring a global outbreak of the virus.
The WHO said the virus appeared to be taking hold outside of North America.
The overwhelming majority of cases and deaths have been reported in Mexico and the US, but increasingly the virus is spreading from person to person in countries as far apart as Britain, Spain, Japan, Chile and Australia.
The number of swine flu cases worldwide has reached 19,273, according to the WHO's latest figures.
The virus has been confirmed in 66 countries.
The WHO said the death toll from the virus stands at 117.