The spectrum of HIV mother-to-child transmission risk

With the implementation of combined antiretroviral therapy (cART) and prevention of mother-to-child transmission (MTCT) we observed dramatic decreases in rates of perinatal MTCT of HIV, 0.3% in France in women with plasma viral load (pVL) <50 c/mL at delivery. We describe a case of MTCT which occurred despite virologic suppression of the mother at delivery, the first case in our centre since 2002.

A 26-year-old black woman, Guinea-native, living in France since 2007, was diagnosed with HIV-1 CRF02 in 2008 and lost to follow-up since November 2012 after second delivery (2 female born in March 2009 and October 2012, uninfected). Third pregnancy began in July 2013 and baseline characteristics in September were as follows: week 13 of gestational age (GA), CDC stage A, CD4 317/mm(3), pVL 4.89 log c/mL. cART with abacavir/lamivudine and atazanavir/ritonavir 300/100 mg daily (qd) was introduced. VL decreased to 2.4 log c/mL in 4 weeks and CD4 increased to 456/mm(3). In December, at week 22 of GA, viral rebound at 4.14 log c/mL due to sub-optimal maternal adherence was observed. After counselling, pVL decreased to 1.69 log c/mL in March 2014, at week 35 of GA and 1.3 log c/mL at delivery. As pVL was <400 c/mL at week 36 of GA, vaginal delivery with IV zidovudine was decided. However, because of poor/uncertain maternal adherence to cART, the neonate was treated with a combination of 2 drugs (lamivudine-nevirapine) with the 4-week zidovudine regimen, until the result of delivery pVL. This combination was stopped at day 2 when maternal delivery pVL (22 c/mL) was received and standard oral zidovudine prophylaxis was continued. Infant was tested for HIV infection at baseline (day 3) and found to be HIV-infected (HIV-RNA 60 c/mL) attesting in-utero HIV transmission. On day 15, zidovudine prophylaxis was discontinued and treatment for HIV infection initiated with standard cART according to the French Paediatric Antiretroviral Guidelines.

The risk of HIV acquisition is low in infants born to women who receive standard cART during pregnancy and labour and achieve undetectable VL at delivery. However, transmission remains a hazard, with possibility of in-utero infection during episodes of non-adherence, and the risk of a possible MTCT has to be mentioned to all pregnant women.