A poster of an Irish study presented at the joint 2008 ICAAC / IDSA in Washington, DC shows the US recommendation of HIV-exposed infants getting 6 weeks of HIV therapy to prevent mother-to-child transmission (MTCT) can be shortened to 4. The study mentions the US Guidelines' lack of definitive evidence supporting its recommendation as a reason for pursuing the retrospective review of data.

This audit of the Irish Prevent MTCT program examined the pregnancies of 868 women from January 1999 to December 2007. Depending upon the child's risk of exposure, one of two regimens were given to HIV-exposed infants: monotherapy with Retrovir (zidovudine, AZT) or three-drug therapy with Retrovir + Viramune (nevirapine) + Epivir (lamivudine, 3TC). Risks of exposure included the mother's non-adherence to HIV therapy, uncontrolled viral load, extended exposure to natal blood during delivery, and short time on therapy (<4 weeks).

Excluding those infants that were lost to follow up, had moved or had died, the researchers confirmed the serostatus of 835 of them. All of the children had received 4 weeks' worth of treatment. The data showed that the MTCT rate equaled 1%, which is lower than global standards of an acceptable MTCT rate.

The presenters emphasized several advantages to these findings. First, reducing the time that an infant must be on therapy by a third has the potential to reduce toxicities. This shorter therapy may also be a more appealing option for parents making this decision to treat their infants. Lastly, a shorter time on therapy is likely to improve adherence and will cut health care costs.

Although this sounds promising, these data come from a retrospective study rather than the more compelling data that would result from a prospective study. These results likely won't be enough to encourage the US to change its Guidelines, but they may persuade prospective study of this issue. In the end by shortening the length of therapy by a third while maintaining its effectiveness, it's a step forward to prevent HIV infection in infants.