The New South Wales case of BT v Oei [1999] NSWSC 1082 directly addresses the duty of care a medical practitioner owes to a third-party sexual partner. In that case, the defendant medical practitioner was found to have a duty of care to a patient’s sexual partner, even though the partner was not, herself, a patient of the medical practitioner. The case involved a man (AT) who reported a flu-like illness in late 1991, and developed acute hepatitis B and a urinary tract infection in early 1992.
A woman called BT subsequently formed a sexual relationship with AT and acquired HIV. Despite the medical practitioner’s testimony to the contrary, the court found that he did not recommend HIV testing.
As a result, AT was unaware of his HIV status and subsequently passed HIV to BT. BT sued the medical practitioner claiming that his failure to diagnose AT’s HIV-positive status was negligent.
BT asserted, and the court agreed, that the medical practitioner should have advised AT to have an HIV test when AT first presented. The medical practitioner owed a duty of care to AT. The court considered whether the medical practitioner also owed a duty of care to BT, and found that he did.
Justice Bell, in finding for BT, took note of the provisions of in the Public Health Act 1991 (NSW) (as the law then was) that required a medical practitioner who believed a patient has HIV to inform that patient of the reasonable precautions the patient should take to protect others against transmission of HIV and the danger of the transmission of HIV.
Justice Bell found the medical practitioner negligent in failing to identify the risk of a HIV-positive status. If the medical practitioner had suspected a HIV-positive status and had followed the dictates of the Act that applied at the time, then, on the balance of probabilities, AT’s HIV-positive status would have been diagnosed early enough for him to have practised safe sex with BT, and BT, again on the balance of probabilities, would not have acquired HIV.
Note: Although the Public Health Act 1991 (NSW), which was in force at the time of this decision, has been subsequently repealed, similar provisions apply today: see s 78 of the Public Health Act 2010 (NSW) and 63 of the Public Health Regulations 2022 (NSW).
For more detailed information about a patient’s responsibility to take reasonable precautions and a medical practitioner’s duty to warn, see the Reasonable precautions and duty to warn section.
