Effects of intensified prophylaxis during the post-natal phase on mother-to-child transmission of HIV-1. The ANRS CO1- French Perinatal Cohort EPF

Background: Intensification of prophylaxis in the neonate is empirically recommended as “post-exposure” prophylaxis against HIV-1 transmission if the mother received no or a sub-optimal antepartum antiretroviral (ARV) regimen. Its efficacy has not been established for non-breastfed children.
Methods: The transmission rate associated with 4 to 6 weeks of zidovudine monotherapy was compared with that for all types of intensification (≥2 drugs) in 4730 neonates with well established HIV status, excluding in utero transmission, in the French Perinatal Cohort between 2000 and 2007.
Results: Less than 1% of neonates received no postnatal prophylaxis, 86% zidovudine monotherapy, and 13% ≥ 2 drugs (intensification). Despite national guidelines, only 42% of neonates born to mothers without any ART during the pregnancy received postnatal intensification, the other infants receiving monotherapy: the transmission rate was significantly lower following intensified prophylaxis (0%) than zidovudine only (13%) ; p=0.01. By contrast, for mothers treated during the pregnancy who had low viral loads at delivery (< 400 cp/mL), the transmission rate did not differ between the 381 children receiving >2 drugs and the 3394 receiving monotherapy (0.5% vs. 0.4% ; p=0.7). Only 25% of the 269 treated mothers with viral load failure at delivery (>104 cp/mL) received intensification, with no difference of transmission rate (5.6% with intensification vs 2.5% ; p=0.2).
Conclusions: These data support the use of post-natal intensification when the mother does not receive therapy during pregnancy. When the mother's viral load is controlled at delivery, intensification seems not offer significant added protection. Regarding mothers with high delivery viral load despite ART, we showed no association with post-natal intensification, but lack of powerful and bias cannot be excluded considering the unexpected low proportion of neonates receiving intensification in this situation. These findings may lead to a new prophylactic approach in case of HIV diagnosis in the delivery room.

J. Warszawski1,2,3, A. Faye4, E. Emmanuelle1, C. Dollfus5, R. Tubiana6,7, C. Rouzioux8,9, J. Le Chenadec1, J.-P. Teglas1, L. Mandelbrot1,10,11, S. Blanche8,9, ANRS CO1-EPF
1Team HIV/IST - CESP- INSERM U1018, Le Kremlin-Bicêtre, France, 2Univ Paris-Sud, Le Kremlin-Bicêtre, France, 3AP-HP, Groupe Hospitalier Bicetre, Le Kremlin-Bicêtre, France, 4AP-HP, Hôpital Robert Debré, Paris, France, 5AP-HP, Hôpital Trousseau, Paris, France, 6AP-HP, Hôpital Pitié Salpêtrière, Paris, France, 7INSERM U943, Paris, France, 8EA 3620, Université Paris Descartes 5, Paris, France, 9AP-HP, Hôpital Necker, Paris, France, 10AP-HP, Hôpital Louis Mourier, Colombes, France, 11Univ Paris 7, Paris, France