Antiretroviral therapy (ART) initiated soon after primary infection is thought to influence seeding of the viral reservoir with beneficial effects for virologic control. Infants are an important group who can be identified soon after infection. Here we describe virologic dynamics following early ART in infants.
For the past 2 years, HIV PCR testing has been offered for all HIV-exposed newborns at Rahima Moosa Mother and Child Hospital in Johannesburg, South Africa. Standard HIV PCR tests are done at the national laboratory. On weekdays when staff capacity permits, point-of-care HIV PCR tests are concurrently done. All infants with reactive PCR results are actively traced for confirmatory testing and engagement in care. ART is initiated as soon as possible with nevirapine, lamivudine and zidovudine with substitution of lopinavir/ritonavir for nevirapine at 2 weeks or later. HIV RNA is measured in plasma at frequent intervals using Roche AmpliPrep/COBAS TaqMan with a lower detection limit (LDL) of 20 copies/ml and qualitative HIV diagnostic PCR tests are repeated.
To date we have identified 100 HIV-infected infants as part of the birth PCR testing program (~1.5% of HIV-exposed infants tested). Of these, 68 HIV-infected infants have been enrolled into a clinical trial tracking their response to ART. Half of these infants started ART within the first 2 days of life (n=34), 25% started 3-7 days (n=17), 15% 8-15 days (n=10) and 10% 16-104 days (n=7). Three infants died in the first months of life, all of whom had started ART within the first 2 days. To examine viral response, we restricted analysis to infants who started ART 0-15 days and were alive and still in follow-up at 6 months. 11% of treated infants have persistently high HIV RNA levels, 35% have a declining trajectory that has not yet reached LDL, and 54% have declined to LDL or target not detected (TND) of the assay. Of those who achieved suppression by 6 months, 30% have changed to having a negative diagnostic HIV PCR during follow-up. Figure 1 shows the viral dynamics in the first year of life of the 34 infants who started ART 0-2 days.
There is variability in virologic response to early ART among HIV-infected infants identified at birth. Many clinical and social challenges affect engagement in care of this high risk group of infants. Follow-up is on-going and updated data will be provided.