IRISH medical experts were last night quick to reassure the 105 patients who were treated this year in hospitals in Letterkenny and Limerick by a doctor who has since tested positive for HIV. The chances of any of the patients contracting the virus are "very slim" according to a Dublin AIDS expert, Dr Fiona Mulcahy.
Dr Mulcahy, a genito urinary physician at St James's Hospital, said no evidence of transfer of the virus has been found in look back programmes carried out internationally after patients were treated by healthcare workers found to be HIV positive.
She said that danger existed in an exposure prone procedure where a surgeon's hands were out of sight in a body cavity. If the surgeon was to be cut with a sharp instrument or suffer a needle stick injury, the surgeon would have to have a significant bleed into the patient's blood to transmit the virus.
Dr Mulcahy pointed out that a doctor at junior level would not be performing highly invasive surgery, but would be involved in operations such as appendicectomies or in stitching up after surgery.
There was a much smaller chance of contracting HIV than hepatitis B or C, she explained. Anyone sticking themselves with a blood filled syringe would have a one in 300 chance of contracting HIV, compared to a one in three chance of hepatitis B or one in 30 chance of hepatitis C.
The only previous record of transmission from a healthcare worker to a patient is the case of a HIV infected Florida dentist who infected six patients from 1990 onwards. There is still controversy as to how this transmission occurred. Dr Mulcahy said there has been speculation about this doctor using instruments on himself and then on his patients.
The transmission rate risk from a patient with HIV to a healthcare worker is far higher than the other way around, according to Dr Gerard Sheehan, consultant in infectious diseases at the Mater and Beaumont hospitals in Dublin. He confirmed that the risk to patients from the doctor working in Letterkenny and Limerick was "very low".
Irish patients should take comfort from a study carried out by the Centre for Disease Control (CDC) in Atlanta, Dr Darina O'Flanagan, specialist in public health medicine with responsibility for communicable disease control with the EHB, told The Irish Times last night.
"There have been numerous studies which show transmission did not occur," said Dr O'Flanagan.
The CDC study, published in 1993, looked at patients treated by people with HIV. The paper, "Investigations of Persons treated by HIV infected Health Care Workers United States" found that no patient had contracted HIV from a healthcare worker (HCW) who had the virus. The research involved 19,036 people who were treated by 57 HIV infected HCWs.
It found that 11,529 patients who had come into contact with 46 of the HCWs were clear. Five surgeons and obstetricians were included in this group.
For the remaining 11 HCWs, 7,507 patients were tested and 92 tested positive for HIV follow up investigations have been completed for 94 per cent of these patients. Eight had been infected before treatment, 54 had established risk factors for HIV, 19 may have had other opportunities for exposure to HIV such as multiple sex partners and five had no risk identified.
The study then compared the genetic sequencing on the HIV strains of the HCW and the patients who had tested HIV positive. It showed that the strains between the patients and the HCW were different.
This was not performed on two of the five patients who had no identified risk because one patient died before a blood sample could be collected and the other refused to provide a sample.
"Follow up to date has not demonstrated transmission from a HCW as a source of HIV infection for any of the patients tested," said the study.
Another study in the US, Dr Sheehan pointed out, showed an average of four needlestick injuries per 1,000 hours of operating for surgeons.
"A surgeon might work an average of 1,000 surgery hours a year. These injuries are part of the art of surgery or dentistry," said Dr Sheehan. "The key thing is when they occur in exposure prone surgery where the surgeon's hands are in the middle of a body cavity."
Dr Mulcahy said the only HIV positive people prevented from working in their chosen field were obstetricians, gynaecologists, surgeons and dentists who were doing invasive and exposure prone procedures.