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PHS Report Summarizes Current Scientific Knowledge on the Use of Post-Exposure Antiretroviral Therapy for Non-Occupational Exposures
Therapy Remains Unproven: Should Not be Used Routinely

September 1998

In recent years, the Public Health Service (PHS) has recommended the use of antiretroviral drugs to reduce the risk of occupational HIV transmission following workplace exposures (e.g., health care workers exposed through accidental needle-sticks). Scientific studies have shown the drugs to be both safe and effective for this use. While this type of therapy is not 100% effective, it has been found to significantly reduce the risk of HIV infection among health care workers following percutaneous (through the skin) exposures.

Questions have arisen about whether similar therapy should be offered to people with unanticipated sexual or drug injection-related exposures to HIV. However, researchers do not know if findings among health care workers are applicable in other settings where therapy may not be initiated as quickly, where the HIV status of the source may not be known, where the regimen cannot be closely monitored, and where repeated exposures may occur. To consider these questions, PHS convened scientific experts from across the nation to review all available data. The September 25, 1998, issue of the Morbidity and Mortality Weekly Report summarizes the data considered and the outcomes of this consultation.

While the number of AIDS cases is declining, the number of people living with HIV infection is growing. This increased prevalence of HIV in the population means that even more prevention efforts are needed, not fewer. For individuals at risk, increased prevalence means that each risk behavior carries an increased risk for infection. This makes the danger of relaxing preventive behaviors greater than ever.

PHS has concluded that there are no conclusive data on the effectiveness of antiretroviral therapy in preventing HIV transmission after non-occupational exposures. It is therefore not possible to make definitive recommendations regarding its use. Because the therapy remains unproven and can pose risks, physicians should consider its use only in individual circumstances when the probability of HIV infection is high, the therapy can be initiated promptly, and adherence to the regimen is likely. It should not be used routinely and should never be considered a form of primary prevention.

Decisions regarding use should be made by physicians, in consultation with their patients and, as needed, an expert in the use of antiretroviral drugs. To help guide these discussions, the PHS report provides physicians a summary of available data and outlines factors that should be considered before prescribing therapy. The following factors should be evaluated in considering the potential benefit of therapy:

Potential benefits must be weighed against the risks of drug toxicity, the difficulty of compliance with the regimen, and the potential for individuals at risk to abandon more effective prevention strategies. Because post-exposure is an experimental therapy of unproven efficacy, it should only be prescribed with the informed consent of the patient, after explanation of the potential benefits and risks. Antiretroviral therapy should never be used routinely and should not be used when there is a low risk of transmission or when people seek care too late to anticipate an interruption in transmission.

The report also requests that physicians notify CDC of all cases in which post-exposure therapy is prescribed for nonoccupational exposures. Data collected through the CDC reporting system on the utilization, effectiveness, and toxicity of this therapy may provide the information needed to refine future recommendations.

Primary conclusions of the report include:

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