High prevalence of low-level viremia among infants initiated on antiretroviral drugs following mother-to-child transmission of HIV.

Background: With the current elimination of mother to child transmission (EMTCT) of HIV, the number of HIV-positive newborns has greatly reduced. Some countries have successfully eliminated HIV infections among newborn babies.

Methods: This study was nested within the DRIBS (Drug Resistance testing among Infants at Baseline Study), which enrolled 100 infants at the time of treatment initiation between 2017 and 2023. Infants were followed for two years. Viral load (VL) was measured every six months and after completion of the three sessions of intensified adherence counseling (IAC). IAC and HIV drug resistance testing were performed for VL greater than 1000 copies/ml.

Results: The median age at diagnosis was 79 (IQR, 57.75;140.75) days, with 4% of patients diagnosed within 6 weeks after delivery. The median age at the initiation of therapy was 110.5 (IQR, 87.0-162.0) days. The median baseline %CD4 was 26 (IQR, 18.75;32), with 9% of the babies being severely immunosuppressed (%CD4 < 15%). The median baseline log viral load was 4.44 (IQR, 3.19-5.58). At six months, 30% and 60% of the patients had a VL < 50 and < 1000 copies/ml, respectively. At 12 months, 36% and 69% of patients had a VL < 50 and < 1000 copies/ml, respectively. At 24 months, 63% and 83% had VL < 50 and < 1000 copies/ml, respectively. Post-IAC VL revealed that 35% of the children had low-level viremia (LLV) compared to mothers 11.5%. Kaplan-Meyer survival estimates showed that while it took 72 weeks for 50% of the mothers and infants to attain a VL less than 1000 copies/ml, it took 96 weeks for the infants to attain a VL < 50 copies/ml.

Conclusion: A Viral load < 1000 copies/ml is achieved much more slowly in pediatric patients, implying that it might take longer for babies to achieve the third 95 (95% virally suppressed) of the UNAIDS targets. Furthermore, the greater prevalence of LLV in pediatric patients than in mothers has important implications for the response to therapy.