Eton College is due to remain closed until Sunday
A further 23 cases of swine flu related to the Eton College outbreak have been confirmed by health officials over the past two days.
Sixteen cases were confirmed on Tuesday with at least another seven confirmed on Wednesday. At least 18 are pupils, the Health Protection Agency said.
The exclusive Berkshire school remains shut for an extra week after half-term, until Sunday, because of the virus.
Parents have been emailed by the school to say that will be reviewed on Friday.
The 23 cases established in the past two days brings the total number of cases linked to the school to at least 27.
The school authorities have said it could remain closed for a longer period since more boys have been diagnosed.
Headmaster Tony Little said in an email to parents: "Boys who have returned for exams have been checked for any symptoms.
"Some boys have been asked to stay away until they are clear.
"Some of the boys who tested positive have recovered fully and are back for exams."
"Our objective is still to reopen on Sunday evening, and to this end we will stay in close touch with the HPA about any developments over the next few days," he added.
The total number of people diagnosed with swine flu across the UK is 381.
Eton, which was attended by Princes William and Harry, was shut for half-term when the first case - a 13-year-old - was announced last week, and was advised to remain closed for an extra week after the positive test.
Three more cases were confirmed at the weekend.
In a letter to parents, the HPA said it had "decided to offer antiviral [medication] for all the students and staff to minimise the likelihood of the virus spreading to students and families not already affected".