• NHS England says patients will be warned they could be at low risk
  • Twenty-eight known cases of mycobacterium chimaera infection including 15 people who have died
  • Infection risk identified in other countries linked to heater/cooler devices

NHS England is writing to thousands of patients who have had open heart surgery to warn them they may be at risk of an infection that has killed 15 people.

The national commissioning body said the letters were a “precautionary step” to alert patients to what it described as a “low risk” of infection caused by mycobacterium chimaera.

Letters will be sent to patients in England, Scotland, Northern Ireland and Wales who have had heart valve replacement or valve repair surgery since January 2013. It will also include children who had surgery for congenital heart disease.

The infection risk is a global issue resulting from potential contamination of machines used to heat and cool a patient’s blood during surgery.

In November 2015 new guidance was issued by Public Health England and Medicine and Healthcare Products Regulatory Agency. No cases of the infection have been identified in patients since then.

As of 17 March 2017, PHE said it was aware of 28 cases of infection by the bacteria following surgery of cardiopulmonary bypass. Of those 28 infections, 15 patients are known to have died. The bacteria has a long incubation period with the median time to diagnosis being 19 months.

A statement by health minister Nicola Blackwood earlier this month said six cases had been diagnosed in 2016, 11 in 2015 and two in 2014.

NHS England has said around one in 5,000 patients who have had valve surgery will contract the infection.

In a statement on its website NHS England said: “This is a precautionary exercise. The risk of contracting the infection is considered low, and it cannot be spread from person-to-person. There is no need for those who have already had valve replacement or repair surgery to be concerned unless they experience symptoms of infection.”

Symptoms include unexplained fevers or night sweats; unexplained weight loss; increasing shortness of breath; joint or muscle pain; nausea, vomiting or abdominal pain; abnormal levels of tiredness or fatigue; and pain, redness, heat or pus around the surgical site.

Patients with these symptoms should contact their doctor, even if their surgery was many years ago.