Malware problems in Sheffield hospitals have lead to patient appointments being cancelled, according to the Sheffield Teaching Hospitals NHS Foundation Trust.

The Conficker B virus infected 800 out of the 7,000 PCs at five hospitals in Sheffield on 29 December and three weeks after it first hit, engineers are still trying to eradicate the problem.

The virus first hit when Microsoft Windows automatic security updates were disabled on PCs in operating theatres.

Contain and destroy

David Whitham, informatics director at Sheffield Teaching Hospitals NHS Foundation Trust, said: "There has been limited impact on patient care. The virus has now been contained and our IT team have been working very closely with external antivirus specialists to update PCs and remove the last remnants of the virus from the network to limit the chances of a repeat infection.

"The automatic Microsoft update process had been temporarily disabled following problems with some PCs providing supporting information in theatres.

"This decision was taken by the IT Change Advisory Board to prevent further disruption in theatres."

The Conficker virus has infected over nine million machines worldwide over the last month.