Current treatment options to prevent perinatal transmission of HIV

Abstract

Mother-to-infant transmission is the primary means by which young children become infected with HIV. WHO estimates approximately 1600 infants become infected with HIV every day. Recent advances in identifying the factors determining perinatal transmission have allowed interventions to be made to reduce mother-infant transmission. Paediatric AIDS Clinical Trials Group (PACTG) protocol 076, the pivotal vertical transmission study demonstrated that zidovudine (AZT) in pregnancy could reduce perinatal transmission of HIV-1 by 67%. This was confirmed by PACTG 185, in pregnant women with more advanced disease, which also demonstrated that viral load was the only independent factor determining vertical transmission rate (VTR). More recently, results from several short-course antiretroviral trials have brought new hope, that effective preventative interventions can be extended to developing countries. Although most studies have involved shorter versions of PACTG 076, the latest finding from HIVNET 012 demonstrated a significant reduction in VTR using a two-dose regimen of nevirapine (NVP). This intervention is the simplest, least expensive regimen so far with proven efficacy in diminishing mother-infant transmission. Non-pharmacological interventions have also been studied recently. The benefits of elective caesarean section (ELCS) have been clearly demonstrated in recent studies. These studies were carried out at a time when highly active antiviral therapies (HAART) were not available. There is still no information as to whether ELCS provides any added benefit for women on HAART with an undetectable HIV viral load. Prevention of breastfeeding can also further reduce VTR. This strategy is more applicable to resource-rich countries where access to formula feeds is not a problem. Options to prevent perinatal transmission must take into consideration the economic climate in which the intervention is to be made. In developed countries, effective intervention with perinatal AZT, ELCS and exclusive formula feeding has already reduced the VTR to around 1%. There is limited safety data currently available on the use of other antiretrovirals in pregnancy. A cautious approach to the use of HAART in pregnancy is recommended at present.

• antiretroviral therapy
• breastfeeding
• caesarean section
• HIV
• lamivudine
• nevirapine
• pregnancy
• vertical transmission
• zidovudine