Background

WHO convened a technical consultation in Geneva on 5 and 6 February 2004 with scientists, policy-makers, programme managers and community representatives to review the experience with programmes and recent evidence on safety and efficacy of different antiretroviral (ARV) drug regimens for the prevention of mother-to-child transmission (MTCT) of HIV. This information was reviewed in the context of rapid expansion of ARV treatment in resource-limited settings using simplified and standardized drug regimens. Prior to the consultation a draft set of recommendations had been issued for public comment, which is now under revision in the light of comments received and the recommendations made at the technical consultation.

Key recommendations

• Women who need ARV treatment for their own health should receive it, following revised ARV treatment guidelines recently posted by WHO. The use of ARV treatment when indicated during pregnancy will improve the health of the mother and substantially decrease the risk of transmission of the HIV virus to the infant.
• Women who do not need treatment, or do not have access to treatment, should be offered ARV prophylaxis to prevent MTCT using one of a number of ARV drug regimens known to be safe and effective.
• The most efficacious regimen among those recommended for prevention of MTCT for women with HIV who do not need ARV treatment is zidovudine (ZDV) from 28 weeks with single dose nevirapine (NVP) at onset of labour for the mother and single dose NVP plus one week ZDV for the infant.
• Alternative but less efficacious regimens include one based on ZDV alone (from 28 weeks of pregnancy and through labour for the mother and for one week for the infant), one using the combination of ZDV plus lamivudine (3TC) (from 36 weeks of pregnancy, through labour and one week postpartum for the mother, and for one week for the infant), and a regimen comprising a single dose of NVP to the mother and to the infant (which does not need to be initiated until labour).
• The selection of the ARV drug regimen should be made at national level, based on issues of efficacy, safety, drug resistance, feasibility, and acceptability.

The consultation participants made these recommendations based on a thorough review of the current evidence and careful consideration of issues of efficacy, safety and practicality.

New data reviewed

In particular, the consultation participants reviewed available scientific evidence on the emergence of resistant HIV strains associated with use of some ARV drugs for prophylaxis, which has raised concerns about future ARV treatment options for the mother or, if infected, the infant. They felt, however, that the evidence regarding the degree of impact of such resistance is not as yet conclusive. New data from the observational study conducted by Lallemant et al. in Thailand suggest that the regimen of ZDV and single dose of NVP could dampen the mother’s response to ARV treatment initiated in the first months after delivery. These data were taken into account in developing the above recommendations. However, the consultation participants felt that the implications of these preliminary data on subsequent treatment options for women were unclear and require further study. They noted that more definitive clinical trials assessing this issue are under way. Until further evidence is available it was the group’s expert opinion that the ZDV plus single-dose NVP regimen can be recommended for the prevention of MTCT because of its considerable efficacy in reducing MTCT (by 80%, from the transmission rates observed with short-course ZDV alone, down to an absolute level under 2%), its simplicity and its safety profile for mother and infant. In view of these results, the government of Thailand is implementing this regimen nationwide for the prevention of MTCT, alongside its efforts to scale up ARV treatment for all in need.