Association between infant post-natal prophylaxis regimens and pretreatment HIV drug resistance in infected infants.

BACKGROUND: Antiretroviral drugs for preventing mother-to-child transmission (PMTCT) can lead to NRTI resistance in infants who contract HIV despite prophylaxis. We aimed to assess how different post-natal prophylaxis (PNP) strategies; nevirapine (NVP) alone vs zidovudine (ZDV) alone vs dual NVP + ZDV influenced NRTI resistance prevalence. METHODS: We analyzed data from nationally representative HIV drug resistance surveys conducted in Kenya where the standard practice was the use of dual NVP + ZDV and Nigeria where the standard practice was the use of NVP PNP. HIV drug resistance was determined using population-based sequencing, and mutations interpreted using the Stanford HIVdb algorithm. Analyses were weighted for multistage sampling and genotyping success rates. RESULTS: Among 557 HIV-infected infants aged <18 months with data on resistance and type of PNP, 29.3% received dual NVP + ZDV PNP, 24.6% received NVP alone, 2.3% received ZDV alone, and 43.8% received no PNP. The prevalence of NRTI resistance was 19.4% (95%CI 15.2-24.3) in Nigeria and 9.6% (95%CI 6.6-13.8) in Kenya (p < 0.001). Resistance to abacavir, lamivudine, zidovudine and tenofovir were 2- to 4.5-fold higher in Nigerian HIV infected infants exposed to NVP PNP compared to Kenyan infants exposed to NVP + ZDV. The proportion of infants with NNRTI resistance was 49% (95%CI 43.5-54.5) and 43.8% (95%CI 38.0-49.7), in Nigeria and Kenya respectively (p = 0.204). CONCLUSIONS: These findings suggest an association between type of PNP and the development of NRTI resistance in HIV-infected infants. Dual-drug prophylaxis was associated with a low prevalence of NRTI resistance compared to single-drug PNP. Our findings highlight the need for further research on combination prophylactic strategies in minimizing the emergence of drug resistance in this population.