A British mom is warning others about the dangers of the flu after her 8-year-old son was hospitalized with the virus.

Janine Riley, 44, of Wadebridge, Cornwall, told South West News Service (SWNS) that her son Henry — who she described as a “fit and healthy” boy who enjoys playing rugby — recently came home complaining of a stomach ache. But his symptoms quickly worsened, developing into a high fever. The young boy also had difficulty breathing, she said.

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“He was fine one day, playing rugby, came home with a tummy ache. We put him to bed with paracetamol and ibuprofen. The next day he was [in poor condition], very hot,  and struggled [to breathe]. So we called an ambulance and within a few minutes he had been rushed to the hospital,” she recalled.

Young Henry Riley pictured in hospital as he was treated for the flu. (SWNS)

Henry was placed in intensive care. He also required a ventilator for three days.

Though the 8-year-old made it out of intensive care, his battle was not yet over.

"We had lots of physiotherapies, getting him to breathe again. He couldn't stand up, he couldn't walk,” said Riley.  "He'd gone in a few days from being a fit, healthy 8-year-old boy to not being able to walk down the corridor, it was really sad."

It's not clear if Henry had received the flu vaccine prior to falling ill. (SWNS)

Riley did not say whether or not Henry had been vaccinated against the flu prior to falling ill.

Health professionals recommend that everyone receive the flu vaccine. But they especially encourage pregnant women, young children and the elderly to get the shot, as they are often the most susceptible to the virus.

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“The flu shot is incredibly important because it reduces your risk of contracting the flu,” Michelle Lin, an emergency room doctor, and professor of emergency medicine at Mount Sinai in New York City, previously told Fox News. “It also reduces your risk for complications and passing it to other people.”

Public Health England (PHE), an executive agency apart of the Department of Health and Social Care, is offering a free flu shot to an additional 600,000 children ages 10-11 this year. Children ages two to 11 will also be offered the nasal spray version of the vaccine, according to the Guardian.