Townsend et al., Earlier initiation of ART and further decline in mother-to-child HIV transmission rates, 2000-2011. AIDS, 2014; 28 (7): p. 1049-57.
Amongst many of the problems that women with HIV-positive women face is the risk of transferring that to a child during pregnancy or birth. The risk during this process is highest during the actual delivery process because that’s when the water breaks and the child is more exposed to maternal fluids. However, as the years go by and having HIV has become less of a deadly disease and more of a manageable condition and the therapies that are offered become more sophisticated, Townsend et al. set out to measure whether this improvement in adult treatment was also resulting in fewer instances of mother-to-child HIV transmission. Between 2000 and 2011, 12486 births by mothers with HIV were recorded in the UK and Ireland. The HIV infection status of 92.2% of these children was known.
Although the number of HIV-positive-mother births increased per year from 816 in 2000-2001 to 1975 in 2010-2011, the absolute numbers of mother-to-child transmission actually decreased significantly from 17 to 9 (2.1% to 0.46%). In addition to studying the number of transmissions Townsend et al. also investigated the various causes that led to this improvement. Mother-to-child transmission was significantly related to the viral load that the mother was carrying: 1% for 50-399 copies/mL vs. 0.09% for less than 50 copies/mL. Additionally, the risk of mother-to-child transmission was significantly reduced in women with higher load when they elected to have a cesarean section (0.26%) vs. vaginal delivery (1.1%). The main attribution to lower across-the-board transmission rates is the proactive use of anteneonatal combination antiretroviral therapy, which lowers viral copy number. Indeed, even a few weeks of antiretroviral therapy could significantly reduce the risk of transmission during birth, with a stabilizing protective effect after about 15 weeks (depending on the baseline viral load).
This study is a great example into how a system-wide improvement in the recognition of HIV-positive mothers and proactive cART treatment starting early in pregnancy, coupled with informed decisions on birth methods can lead to a significant reduction in mother-to-child transmission. Although ideally there would be better treatment available for the HIV-positive men and women, at least this shows hope for bringing fewer HIV-positive children into the world.