An advertising campaign urges people to catch the sneeze before binning the tissue
Three new confirmed cases of swine flu have been diagnosed in the UK, bringing the total number to eight, the Department of Health has said.
Two of the cases are in London and one in Newcastle. All are said to be responding well to treatment.
Earlier, the government's chief medical adviser warned Britain will see "many, many more cases" of swine flu, although he said most people would recover.
In total, 230 possible flu cases are being investigated in the UK.
The figures include 27 "possible" and one "probable" case in Scotland, according to Scottish Health Secretary Nicola Sturgeon.
She said one patient waiting to hear whether he has swine flu had been in contact with a Falkirk couple who brought the virus back from Mexico.
Ms Sturgeon said: "If this case was confirmed it would be the first case in Scotland of onward transmission, but I stress it's not confirmed at this stage."
There are so far no confirmed swine flu cases in Wales, although 19 people have been tested for the virus.
Six people in Northern Ireland have also been given anti-viral drugs as a precaution, but none of them has tested positive either.
But on Thursday, Irish health chiefs said one man had tested positive for swine flu - the Republic's first.
Despite advice from the World Health Organization that governments should activate their pandemic contingency plans, UK health experts continued to play down the effects of the virus.
Chief medical adviser Sir Liam Donaldson told the BBC the UK was well prepared for the spread of swine flu and that he was "concerned, but not alarmed" about the situation.
He said: "What we will see is many, many more cases, and inevitably some serious cases - but on the whole people make a good recovery from flu."
It was impossible to predict how many deaths there could be in the UK until more was known about the strain of the swine flu virus, he said.
Certain groups would be more vulnerable than others, such as the elderly and very frail, he added.
Sir Liam's reassurances were backed by the news that all British flu cases so far diagnosed are thought to have responded well to treatment.
And the Scottish case notwithstanding, so far the virus does not appear to have spread beyond people who picked it up in Mexico.
The student housemates of the Newcastle patient have been treated with anti-viral drugs, but have so far shown no flu symptoms, said the Registrar of Newcastle University, Dr John Hogan.
BBC correspondent Chris Stewart said he understood four other close contacts of the patient - thought to be a woman - had also received anti-viral drugs.
The patient herself had responded well to treatment and was now at home, he said.
An NHS spokesman said the two new swine flu cases in London - a 23-year-old man from Islington and a 29-year-old man from Westminster - were also being successfully treated at home.
Earlier, Sir Liam had ruled out screening all British travellers returning from Mexico, saying it was more important to "concentrate the public health attention" on those showing symptoms.
Health Secretary Alan Johnson said UK health authorities were doing all they could to contain the virus, but were making preparations in case it spread.
"We are trying to contain it at that level, and we are still succeeding with that. But it is very important that we prepare for that next phase," Mr Johnson said.
In Devon, health experts are attempting to contain a flu outbreak by shutting a school attended by Britain's youngest swine flu patient - a 12-year-old girl.
Paignton Community College will remain shut until 11 May. Year seven students have been given anti-viral drugs.
Other precautions against an epidemic were revealed by Prime Minister Gordon Brown.
He told MPs they included enhanced airport checks, an expansion of anti-viral stocks from 35 million to 50 million by the end of May, extra face masks and information leaflets for every family.
Supplies of antibiotics are to be increased to deal with any complications arising as a result of flu infections, he said.
NHS Direct has taken thousands of calls about swine flu this week, while daily visits to its website have reached 85,000, compared with about 55,000 a week earlier.
An advertising campaign to help prevent the spread of the virus has also been launched.
The Department of Health's Catch it, Bin it, Kill it! adverts urge people to cover coughs and sneezes with tissues, throw them away and wash their hands.
Meanwhile, hundreds of British tourists are flying home on special charter flights from Mexico, where the outbreak started.
Members of the public can call 0800 1513513 for recorded information about swine flu. In Scotland, anyone with concerns about the virus can call 08454 24 24 24.
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