Swine flu 'is not a plague' Sir Liam Donaldson has said as he urged schoolchildren not to shun or bully fellow pupils who have contracted the virus.
Sir Liam, chief medical officer, said instances where children who have caught H1N1 swine flu and been bullied by text message were 'quite wrong' and added: "It is very important not to be complacent but we cannot over react. This is not some plague that has descended on the school."
Earlier this week it emerged Phoebe Wyburd, 12, one of six children at Alleyn's School in Dulwich, south London, to have contracted the virus, was sent a text message saying 'you are going to die'. The school is one of five that closed this week after pupils contracted swine flu on holiday and is preparing to reopen next week.
There have been 13 confirmed cases in children and all have remained isolated at home and are being treated with antiviral drugs. The drug, Tamiflu, has also been given to students who have had contacted with infected pupils as a precaution.
Alan Johnson, Health Secretary, said: "In the early stages the danger was that the outbreak might spread panic, now the danger is complacency."
He said it is reasonable to expect more cases in Britain in the weeks and months ahead and warned that while all the patients so far had been only mildly unwell, scientists cannot rule out that the virus may mutate into a more dangerous form and return in the Autumn.
He announced that a total of 227m face masks had been ordered along with 33m respirators for NHS workers in contact with potentially infected patients in the event of a pandemic.
Sir Liam added that the high temperatures may be inhibiting the spread of the disease in Mexico, the epicentre of the outbreak where there have been 1,112 cases and 42 deaths, and experts would be watching to see how the virus behaves in the southern hemisphere as winter and the traditional flu season starts there.
The worldwide total has now exceeded 2,000 confirmed cases including 34 in Britain.
Sir Liam said early suggestions are that the flu could infect 25 to 30 per cent of the population.
He added that current Health Protection Agency advice that the disease can be passed on by spending one hour within one metre of an infected person may have to be revised as it may be more transmissible than that.
Some scientists have suggested that older people who have lived through previous pandemics caused by H1N1 swine flu may have some natural immunity as the majority of cases of the new disease has so far been in younger adults and children.
Mr Johnson said Britain is still in the containment phase of the outbreak and that it is correct for people in close contact with confirmed or probable cases take Tamiflu as a precaution and to reduce the risk of them spreading the disease. This may change however if large numbers of people become infected as the policy would be mitigation and using Tamiflu for prophylaxis would have little effect and may even encourage the virus to become resistant to it.
Sir Liam dismissed theories that people should catch swine flu now while it is a relatively mild disease and so build immunity to it if it does return in a more virulent form.
When asked if he would feel embarrassed if H1N1 swine flu did not cause a pandemic or serious disease Mr Johnson said he would rather be accused of over-hyping the situation than of not being prepared for a dreadful pandemic that seriously affected citizens.
Sir Liam said he also would rather 'have a bit of egg on our faces' than watch people dying on a bigger scale here than in countries which were more cautious.