The identification of HIV-seropositive patients during retrospective investigations of HIV-infected health care workers is not unexpected, given that approximately 1 in 250 persons in the United States has HIV infection. Higher rates of HIV infection would be expected for patients of health care workers who practice in settings such as correctional facilities or in urban areas with higher prevalences of HIV infection. In the investigations we summarized, most HIV-seropositive patients were either infected before being treated by the HIV-infected health care worker or had established risk factors for HIV infection (for example, male-to-male sexual contact). Patients with histories suggesting potential exposure to HIV outside the health care setting (such as multiple sex partners) were not excluded from further investigation. Rather, investigators focused on these patients and patients with no identified risk factors. Genetic sequencing was done on HIV strains from 16 of the 20 seropositive patients in these two groups and from the 2 health care workers who had treated them; no HIV strains were related either to each other or to those of the health care workers [1].

We agree with Dr. Collignon that the investigations had various limitations, including incomplete data from patients and health care workers [1]. Although data on illnesses possibly related to HIV seroconversion were frequently unavailable, we knew of no patients who had such an illness after treatment. Despite limitations, data from these studies are consistent with the Centers for Disease Control and Prevention (CDC) assessment that, on average, the risk for transmission from an infected health care worker to a patient during an invasive procedure is small. Such transmission has been shown in only one dental practice; the elevated transmission rate to patients in this unusual and poorly understood cluster cannot be used to estimate the risk to patients of other HIV-infected health care workers. Because even the well-planned, systematically conducted investigations to which substantial resources were devoted had limitations, most additional investigations would probably have similar limitations and would not necessarily assist in further clarifying the risk. Investigators from the CDC and elsewhere have concluded that although notification and investigation of patients in whom HIV-infected health care workers did invasive procedures may sometimes be justified, such activities need not be done routinely [2-5].