More than 90 patients at a Royal Free Hospital dialysis centre were at risk of contracting Hepatitis B after a dialysis patient tested positive, it has emerged.

The patient, a 90-year-old male, was having open dialysis for a kidney injury when it was discovered he had the highly infectious virus.

The patient had previously been diagnosed with Hepatitis B and it was believed to have been cleared from his blood stream until tests proved the blood-borne virus had ‘reactivated’.

Following the realisation, 94 patients being treated at the Mary Rankin dialysis centre were contacted by hospital bosses and told they had to be screened.

They were also offered vaccinations or boosters.

Hepatitis B is a virus carried in blood and bodily fluids which infects and damages the liver.

According to a publication produced by the British Liver Trust, it is 50 to 100 times more infectious than HIV.

As the virus can be symptom-less, it is not always diagnosed quickly.

A spokeswoman from the Royal Free Trust told the Ham&High that there was “very little risk” to other patients.

She said: “Patients with reactivated hepatitis B usually have low levels of the virus in their blood, so the risk to other patients is small.”

She added: “Due to swift action, no patients from the group tested positive for the virus.”

The NHS website states that one in 20 cases will result in the virus staying in the body for longer than six months with no symptoms.

This is described as chronic Hepatitis B

The site goes on to explain that patients suffering from ‘chronic Hepatitis B’ pass the virus on to others, even if there are no symptoms.

An estimated 20 per cent of people with chronic Hepatitis B will develop scarring of the liver (cirrhosis) and one in 10 people with cirrhosis will develop liver cancer.

The incident has now been closed by the trust.