Parents who are considering sending their children to "swine flu parties" in the hope that they will contract a mild form of the deadly virus and become immune have been warned off the idea by the Government's Chief Medical Officer.
Sir Liam Donaldson said allowing the H1N1 virus to spread intentionally was "seriously flawed thinking", as not enough was known about it.
"We would never recommend intentionally exposing anyone to swine flu," he said. "It is seriously flawed thinking to allow the virus to spread unabated through 'swine flu parties'. We don't yet know enough about the risk profile of the virus, and while it has generally been mild in the UK, in some parts of the world young previously healthy adults have died.
"Parents would never forgive themselves if they exposed a vulnerable child – perhaps a contact of a child at a party – to serious illness. We need to be mindful of any future development of the virus and we remain vigilant in monitoring the disease."
It has been common for parents to deliberately expose their children to playmates with chickenpox so that they would catch the once-only disease at a time in their lives when there were likely to be few complications.
Some are apparently considering applying the same principle to swine flu, amid fears that a more serious form of the illness will strike in the winter, at a time when stocks of the antiviral drug Tamiflu may be dwindling.
Justine Roberts, the founder of the parenting website Mumsnet, told The Independent yesterday that users had been discussing sending their children to a swine flu party but added she was unaware of any events actually taking place.
"What's being discussed is the principle of whether it might be a good idea, based on the notion that it's better to catch swine flu now than to get it in the winter when Tamiflu's running out, there's a virulent strain around and we're all under the weather," she said. "A lot of people see the rationale behind that."
Ms Roberts said she believed parents had become confused by the Government's policy of keeping schools open while at the same time telling them to take all precautions against their children contracting the virus.
"No one wants to cause hysteria," she said. "The Government has an agenda, I assume, about having to control the infection, but the truth of the matter is either you should get it now or try to avoid getting it – you can't have it both ways. It's so easy to give a glib representation of ignorant parents who are acting hysterically."
On Friday, a six-year-old girl from Birmingham became the third person to die in the UK after contracting the disease. Tests on the body of Sameerah Ahmad revealed she had contracted the virus, but it is not clear whether it was directly responsible for her death.
Yesterday, an inquest into her death heard that she had been born with a life-threatening illness called microvillus inclusion disease, which affects only one person in 1,000. She was also thought to have been suffering from a condition which weakened her bone marrow and her immune system, making it difficult for her body to fight infection.
A further 601 people in the UK were diagnosed with swine flu yesterday, including 394 in England, 196 in Scotland, nine in Wales and two in Northern Ireland. The total number of cases now stands at 6,538.
Ella Thorold, 15: 'I'd prefer to get it now'
I have been to a swine flu party – but it didn't start out like that. It was a regular teenager's party until the conversation turned to swine flu and it turned out that my friend's boyfriend has it so it's likely that my friend, who is also 15, does as well. Everyone started laughing because the idea of a friend having swine flu was quite funny. It was one of those things that you hear about on the news and think will never affect you.
Then, the "swine flu party" started: a coughing fit from my friend all over everyone else. I know that the Government is warning us against these, but I can't see the problem. If I'm going to get it, I'd prefer to get it now, rather than next year which is my final GCSE year, and because apparently it's going to be the winter version of the disease that will be more dangerous.
If I manage to get it now hopefully I can be cured quickly; if I get it in six months, then I'll be shoved in a hospital with thousands of other people who have swine flu waiting for some attention.
And I'm pretty sure that if I managed to get my school closed down for the last weeks of term, I'd be the school hero!