FOUR people are being treated in isolation after doctors found they were suffering with the same flu virus responsible for the 2009 Swine Flu pandemic.

The patients are being kept under watch at the Royal Berkshire Hospital and have been diagnosed with the H1N1 virus, now classified as a seasonal flu.

Hospital staff say the four people, who cannot be named, were admitted to the Craven Road site with other conditions, including bronchitis and chest infections.

But doctors' tests later confirmed they were positive for the H1N1 strain and they have kept them away from other patients.

A spokesman for Royal Berkshire Hospital said: "The Royal Berkshire NHS Foundation Trust is currently treating four patients with community acquired seasonal flu.

"They were admitted because of other related and underlying health conditions. Seasonal flu was diagnosed as part of their hospital investigations.

"All are being treated in isolation. It is the H1N1 virus."

The same virus broke out in 2009 and was referred to as Swine Flu after showing similar signs to a virus found in pigs.

It spread rapidly from country to country because it was a new strain that few people were immune to.

Estimates vary but it is believed that hundreds of thousands of people were killed by the virus worldwide during the pandemic.

According to the NHS 138 people were killed in England during the height of the 2009 pandemic, out of an estimated 540,000 cases.

In August 2010, the World Health Organization declared the pandemic officially over.

The H1N1 virus now circulates across the globe as a form of seasonal influenza.

Symptoms include sudden fever, tiredness, a headache and aching muscles. Most sufferers recover from the virus within a week.

Those in at risk groups, including pregnant women, children and the elderly, are encouraged each year to take up the NHS's free vaccination programme to better protect themselves.