Résumé : Objectives: To evaluate use of combination neonatal prophylaxis (CNP) in infants at high risk for mother-to-child transmission (MTCT) of HIV in Europe and investigate whether CNP is more effective in preventing MTCT than single drug neonatal prophylaxis (SNP). Design: Individual patient-data meta-analysis across eight observational studies. Methods: Factors associated with CNP receipt and with MTCT were explored by logistic regression using data from nonbreastfed infants, born between 1996 and 2010 and at high risk for MTCT. Results: In 5285 mother-infant pairs, 1463 (27.7%) had no antenatal or intrapartum antiretroviral prophylaxis, 915 (17.3%) had only intrapartum prophylaxis and 2907 (55.0%) mothers had detectable delivery viral load despite receiving antenatal antiretroviral therapy. Any neonatal prophylaxis was administered to 4623 (87.5%) infants altogether; 1105 (23.9%) received CNP. Factors significantly associated with the receipt of CNP were later calendar birth year, no elective caesarean section, maternal CD4 cell count less than 200 cells/ml, maternal delivery viral load more than 1000 copies/ml, no antenatal antiretroviral therapy, receipt of intrapartum single-dose nevirapine and cohort. After adjustment, absence of neonatal prophylaxis was associated with higher risk of MTCT compared to neonatal prophylaxis [adjusted odds ratio (aOR) 2.29; 95% confidence interval (95% CI) 1.46-2.59; P<0.0001]. Further, there was no association between CNP and MTCT compared to SNP (aOR 1.41; 95% CI 0.97-2.5; P1/40.07). Conclusion: In this European population, CNP use is increasing and associated with presence of MTCT risk factors. The finding of no observed difference in MTCT risk between one drug and CNP may reflect residual confounding or the fact that CNP may be effective only in a subgroup of infants rather than the whole population of high-risk infants. © 2013 Wolters Kluwer Health