Swine flu girl talks to Sonali
Five schools have now been closed across the UK to stop pupils catching swine flu from each other.
Newsround spoke to one of those pupils, 12-year-old Sophie, and she explained to Sonali what the disease is like.
Sophie said: "It was just a cold, and a cough and a bit of a runny nose and a temperature. I think I'm quite lucky as it's been quite mild."
She added that she was shocked when she found out she had swine flu, saying: "I didn't think it was that bad."
Sophie went on to say: "It's quite weird being kind of part of it. And it's a bit scary that I've got it, because it doesn't really feel like I've got it."
Sophie is one of 32 people in the UK that doctors are sure have swine flu, and they are testing another 390 people to see if the bug they have got is the disease.
Five schools have been closed, three in London, one in Devon and one in south Gloucestershire, after pupils fell ill.
Around the world there are more than 1,658 confirmed cases.
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.
If you want more information, get your mum or dad to call 0800 1513513 for recorded information about swine flu. In Scotland, anyone with concerns about the virus can call 08454 24 24 24.