Government hopes of keeping schools open may founder at the start of the new term.
As a 15-year-old schoolgirl in Glasgow died this week from swine flu, a vigorous debate has begun about whether schools should reopen in August after the summer break.
The girl who contracted the H1N1 virus had underlying health problems and passed away at the Royal Hospital for Sick Children in Yorkhill. No further details are being released at the request of her family.
A total of 20 schools in Scotland were closed at some point between the outbreak earlier this year and the summer holidays, with about 2,000 children affected. But it is now spreading rapidly in England where about 1,000 schools reported cases before the term ended there this week - many fearful parents kept their healthy children off school during the last week.
Of the total number of children affected in the UK, at least 652 are in hospital, including 53 in critical care.
Since last month, government advice has been that containment is no longer possible and schools where pupils have the virus do not have to close.
The Scottish Government has no plans at present to close schools. A spokesman said: "We will keep the situation under close scrutiny, taking into account information on how the pandemic develops and any expert advice as it becomes available."
England's Department for Children, Schools and Families has updated its guidance to schools, saying the summer break may be extended - although it expects schools to reopen as normal in September. It will contact schools during the last week in August to advise them.
Researchers at Imperial College, London, said that early and prolonged school closures could reduce the number of cases at the peak of the pandemic by up to 40 per cent. But, writing in The Lancet Infectious Diseases journal, they said they also found that closures could have no effect: sometimes they came too late, and children mixed outside school.
Mark Woolhouse, a professor of infectious disease epidemiology at Edinburgh University, said the slight fall in cases in Scotland compared with England could be due to the earlier summer school break. However, he said it was "vital" to find out exactly how much transmission of the flu was occurring in schools, as opposed to other places.
But leading Scottish expert Hugh Pennington, a bacteriologist at Aberdeen University, pointed out that The Lancet study cited only a 40 per cent reduction, leaving 60 per cent of cases with the virus. Closing schools would simply be "putting off the evil day, not actually stopping it".
Sir Liam Donaldson, chief medical officer in England, said closing schools would be "extremely disruptive" and added: "When would you open them again, given that flu might be around for months?"
Mick Brookes, general secretary of the National Association of Head Teachers in England, said heads were placed in a tricky situation about whether to open. "The decision would have to be based on the balance of risks," he said. "If a child has underlying health problems, it maybe is reasonable for parents to keep them off. The question is, for how long?"
More than 100 British children and teachers on a trip to China were quarantined in their hotel last weekend after eight were diagnosed with swine flu. They were part of a tour organised by the Specialist Schools and Academies Trust and the British Council.
Open or shut case
- Does school closure halt the spread of flu?
2008: Hong Kong
Primary schools and kindergartens were closed for two weeks after the deaths of two children, apparently from influenza. A reduction in the number of cases followed, but this was expected as the outbreak had already peaked. The reduction was no greater than during a previous outbreak in 2007, when schools remained open.
Three weeks into the outbreak, elementary schools closed because of a teachers' strike; there was a 43 per cent reduction in weekly infections. After the strike, respiratory illness rates rebounded, suggesting the closures had affected the spread.
A recent study of the effect of holidays on influenza-like illnesses found that they prevented about one in six seasonal cases. But the authors pointed out that children's contact with their peers was often reduced during holidays because many went abroad - something they might not do if closures took place in term-time.
Health officials were worried that closures might create a crisis, so they were carried out piecemeal. Decisions to close individual schools were delayed, often until after 50-75 per cent of children had been ill. Late intervention was judged ineffective.
Conclusion: No, too late
Source: The Lancet Infectious Diseases
School closure was just one of several measures - including church closures, the banning of mass gatherings, mandatory mask wearing and disinfection - taken to prevent the spread of the virus. The interventions reduced mortality by 10 per cent to 30 per cent, but it is not possible to estimate the specific effect of school closure.