Ricky's got the latest on swine flu
A 12-year-old girl who's recently been on holiday to Mexico is one of five people in the UK who've got swine flu.
Her school in Paignton, Devon, has been closed to avoid the disease spreading and pupils are being offered medicine to cut the chance of them getting sick.
Experts say there's still no need to panic and every home in the UK will be getting advice on what to do about swine flu delivered through its door.
The government leaflets are designed to help people learn how to beat the bug.
It's thought about 159 people in Mexico may have died because of the virus.
Virus expert Professor Wendy Barclay explains more about swine flu
In the UK, the 12-year-old girl, three men and one woman are the only people who've been confirmed as having swine flu and all are said to be responding well to treatment.
Tests are being carried out on loads more people across the country to find out if they're just ill or if they've also got caught the virus.
UK well prepared
Lots of the symptoms of swine flu are like ordinary flu - a fever, feeling tired, coughing and having a sore throat.
But even if you have all these symptoms, it's REALLY UNLIKELY
you have swine flu as it's still very unusual in the UK.
Doctors who have studied the virus say it's like other types of flu, but has bits mixed into it from the flu bugs that pigs and birds can catch.
Medicine that's used to treat ordinary flu has been helping people with swine flu to get better and scientists are working on a new drug that could stop people catching the bug in the future.
The government says it's really well prepared for the outbreak - it's been stocking up on flu medicine for years and has enough to treat millions of people.
Meanwhile, there are still lots of British people on holiday in Mexico - where swine flu was first found - and they are being checked as they come back to the UK.
Some holiday companies have also cancelled trips to Mexico, and the government's foreign office is recommending that people don't go to the country unless they have to.