Triple antiretroviral medicine regimen more effective for preventing mother-to-child transmission of HIV

21 November 2014

Results from a major clinical trial released on 17 November provide further evidence that triple antiretroviral medicine combinations are more effective than single-medicine regimens in preventing mother-to-child transmission of HIV. Named PROMISE—Promoting Maternal and Infant Survival Everywhere—the trial was conducted in India, Malawi, South Africa, United Republic of Tanzania, Zambia and Zimbabwe.

The findings show that pregnant women with a CD4 count of 350 cells/mm3 or higher receiving a protease inhibitor containing triple antiretroviral regimen were 70% less likely to transmit HIV to their infants than women receiving a single-medicine regime of zidovudine.

Overall transmission rates, measured at two weeks of age, were low across the study, estimated at 0.5% and 0.6% among the mothers using each of the two triple-medicine regimens studied and 1.8% with the single-medicine regimen.

As expected with multiple medicine regimens, the study also revealed more side-effects in women taking the triple combination. While overall the number of women and babies experiencing side-effects was low, there was a higher incidence of maternal liver toxicity, low-birth weight and preterm deliveries with the triple regimen. According to the researchers, balancing the lower risk of HIV infection being passed from mother to baby with the increased rate of side-effects, the triple antiretroviral combination is the more favourable option.

These results confirm the WHO guidelines for the prevention of mother-to-child transmission and are reassuring for the many developing countries that are changing from single (WHO option A) to triple regimens (WHO option B/B+). UNAIDS supports rigorous research, such as the PROMISE trial, which was designed to inform policy and guidelines to enhance the global response to eliminate HIV infection among children.

Since 2011, UNAIDS and partners have been working with countries to reduce new HIV infections among children and strengthen maternal health through the Global Plan towards the elimination of new HIV infections among children and keeping their mother alive, which covers the 22 countries in which 90% of newborn infections occur. By the end of 2013, the participating countries had already registered a 43% reduction in new HIV infections, and eight have reduced new infections by 50% or more. For the first time, all the 22 countries have now adopted the option B triple medicine regimen for the prevention of mother-to-child transmission of HIV. 


“The outcome of the PROMISE trial provides clear evidence for countries that are still implementing option A to move as rapidly as possible to option B/B+.”

Salim Abdool Karim, Chair of the UNAIDS Scientific Expert Panel