CDC recommends immediate HIV drugs after exposureBMJ 2005; 330 doi: http://dx.doi.org/10.1136/bmj.330.7486.274-c (Published 03 February 2005) Cite this as: BMJ 2005;330:274
New guidelines from the US Centers for Disease Control and Prevention (CDC) call for antiretroviral drugs to be given to people who may have been exposed to HIV through sexual intercourse, injection of drugs, or injury. They recommend treatment with highly active antiretrovirals beginning within 72 hours of exposure and continuing for 28 days (MMWR Morbidity and Mortality Weekly Report (Recommendations and Reports) 2005;54(RR02):1-20).
The guidelines say that antiretroviral drugs reduced the rate of transmission of HIV after exposure to the virus in animal studies, in trials looking at prevention of perinatal transmission, in studies of health workers who received prophylactic treatment after exposure at work, and in observational studies.
They say that there is an early window of opportunity to interrupt or prevent transmission. Animal studies of simian immunodeficiency virus showed that the virus first infects cells in the vaginal subepithelium, is found in draining lymph nodes within two days, and spreads to the bloodstream within five days.
Early treatment with zidovudine led to an 81% reduction in risk of acquiring HIV in healthcare workers who had needlestick injuries, a case-control study showed. Several studies cited in the guidelines show that early treatment with antiretrovirals greatly reduced transmission of the virus in high-risk homosexual and bisexual men, women who had been raped, and people who had been exposed to HIV through sex or injection use. The study also noted two cases of high risk exposure (transfusion of HIV contaminated blood and insemination from an HIV positive man) followed by antiretroviral treatment; in neither case did the patient become infected.
Dr Georges Benjamin, executive director of the American Public Health Association, said the guidelines would help people who had obviously been exposed. Patients' compliance was important for successful treatment and to avoid development of resistant strains, so patients must be well counselled, he said. He also said that it was important to continue to stress the importance of practising safe sex and avoiding risky behaviour.
The guidelines recommend 28 days of treatment, beginning as soon as possible before 72 hours after exposure. The preferred treatments are either a non-nucleoside reverse transcriptase inhibitor regimen of efavirenz with lamivudine or emtricitabine and zidovudine or tenofovir disoproxil, or a protease inhibitor regimen of lopinavir and ritonavir (co-formulated as Kaletra) with lamivudine or emtricitabine and zidovudine. Efavirenz should not be used in pregnant women or women of child bearing potential.
The guidelines also say that women who have been raped should be told about emergency contraception—in contrast to recent US Department of Justice guidelines, which did not mention it (BMJ 2005;330:112).
When the HIV status of the source is unknown, and treatment is sought within 72 hours, exposed people and their doctors should evaluate the risks and benefits of antiretroviral treatment. They should consider the risk that the source is HIV positive and the risk of transmission if the source is HIV positive. Treatment is not recommended for people whose exposure doesn't present a substantial risk or who do not seek treatment within 72 hours—but the guidelines say it is unknown whether later treatment will be ineffective.
The guidelines suggest giving patients, who may be under emotional stress, starter packs containing drugs for 3-5 days of treatment and scheduling a follow up visit to review baseline HIV testing, offering counselling and support and adjusting the treatment if necessary. Adherence to the 28 day regimen can be “challenging” and has been shown to be especially poor among people who have been sexually assaulted, so simplifying the regimen, treating side effects, and providing education and support will increase the chances that the patient will complete treatment.
The guidelines are available on the web at www.cdc.gov/mmwr/mmwr_rr.html