A patients' support charity has urged hospital staff to have a greater sense of responsibility after a health worker was diagnosed with HIV and Hepatitis B.
Michael Summers, of the Patients Association, said although it was not known whether the man was aware of his condition until four months ago, more effort should be made by staff to stop working if they suspect they are infected.
Mr Summers said: "It does seem to us that if a healthcare worker has a suspicion that they have an infection, they really need to take themselves off-duty for an investigation.
"They are putting people's lives at risk and that is unforgivable if they are aware that they are ill."
He said it was important for staff to be responsible, no matter how small they believed a risk to be, as it would be impossible for every staff member to be screened.
"It is difficult to make all healthcare workers take tests for every infection," he said.
According to national guidelines, the healthcare worker would have been screened for Hepatitis B when employed by the NHS but not for HIV.
Dr Sue Ibbotson, of the Health Protection Agency (HPA), said: "There is draft guidance dated 2003 which, if it were implemented, would require staff to demonstrate immunity to HIV, but that is still in draft form."
Instead, she said, new staff are asked if they fall into a high risk category for the virus.
If they do, they are tested, but this test is a one-off and is not repeated regularly during their employment.
A spokeswoman for NHS West Midlands said: "There is existing Department of Health guidance that covers the testing and management of Hepatitis B virus in healthcare workers.
"Best practice guidance exists relating to the management of HIV in healthcare workers. This guidance has been developed by experts in this field.
"We will be sharing the learning from this particular case with the national experts for their consideration.
"Hospitals take precautions during all procedures to prevent the spread of infection between patients and health-care workers.
"Guidelines are constantly evolving, but routine testing of all healthcare workers for HIV or other undiagnosed conditions is not policy for any part of the NHS.
"It would mean testing all workers regularly to check that they had not acquired infection.
"It would also require the NHS to test all patients as a routine because the risk of transmission from patient to healthcare worker is greater."
Mr Summers added that in spite of the recall, it was important not to blame the hospitals.
He said: "The hospitals are acting responsibly so you cannot really fault them.
"All you can say to the patients who have received the letter is go into the hospital as a matter of urgency.
"Go in at once - do not delay because there is probably very little likelihood that you have picked anything up but this can act as reassurance."
Dr Rashmi Shukla, regional director of public health for NHS West Midlands, said: "Every effort has been made by the hospitals to trace patients who may be at risk.
"All parts of the NHS involved have carefully identified patients who might have been put at risk of infection.
"This is a highly unusual, if not unique, set of circumstances in that the healthcare worker is infected with both HIV and hepatitis B."
Dr Charles Ashton, medical director of Worcestershire Acute Hospitals, said: "We are sorry for the distress and anxiety that may be felt by those patients contacted. However, it is important that patients are given the opportunity to be fully informed of the risks and be offered tests."