Time to Viral Suppression in Perinatally HIV-Infected Infants Depends on the Viral Load and CD4 T-Cell Percentage at the Start of Treatment

SIV proviruses seeded later in infection are harbored in short-lived CD4+ T cells

The human immunodeficiency virus (HIV) can persist in a latent form as integrated DNA (provirus) in resting CD4+ T cells unaffected by antiretroviral therapy. Despite being a major obstacle for eradication efforts, it remains unclear which infected cells survive, persist, and ultimately enter the long-lived reservoir. Here, we determine the genetic divergence and integration times of simian immunodeficiency virus (SIV) envelope sequences collected from infected macaques. We show that the proviral divergence and the phylogenetically estimated integration times display a biphasic decline over time. Investigating the dynamics of the mutational distributions, we show that SIV genomes in short-lived cells are, on average, more diverged, while long-lived cells contain less diverged virus. The change in the mutational distributions over time explains the observed biphasic decline in the divergence of the proviruses. This suggests that long-lived cells harbor viruses deposited earlier in infection, while short-lived cells predominantly harbor more recent viruses.

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.

Quantification of CD4 Recovery in Early-Treated Infants Living With HIV

BACKGROUND

Perinatally HIV-acquired infants benefit from an early antiretroviral treatment initiation. Thanks to a short viral exposure time, their immune system can be maintained or reconstituted, allowing a "normal" immune development.

METHODS

In this study, we mathematically modeled and quantified individual CD4+ T-cell reconstitution of a subset of 276 children who started treatment within 6 months of age and achieved sustained viral suppression. Considering natural age differences in CD4+ T-cell dynamics, we fitted distances to age-matched healthy reference values with a linear model approaching an asymptote.

RESULTS

Depleted CD4+ percentages (CD4%) and CD4+ counts (CD4ct) restored healthy levels during treatment. CD4ct recovered with a median rate of 4 cells/µL/d, and individual recovery rates were correlated negatively with their initial CD4ct. CD4 values at onset of treatment decrease with age, whereas recovery times and levels seem to be age-independent. CD4 recovery correlates positively with viral suppression, and the stabilization of CD4 levels usually occurs after viral suppression. CD4 levels stabilize within 3-13 months after treatment initiation. The recovery dynamics of the CD4% is comparable with those of the CD4ct.

CONCLUSIONS

In early-treated children with successful viral suppression, the CD4 depletion is typically mild and CD4+ T cells tend to "fully" recover in numbers.

Piloting the Feasibility and Preliminary Impact of Adding Birth HIV Polymerase Chain Reaction Testing to the Early Infant Diagnosis Guidelines in Kenya

BACKGROUND

In Kenya, standard early infant diagnosis (EID) with polymerase chain reaction (PCR) testing at 6-week postnatal achieves early treatment initiation (<12 weeks) in <20% of HIV+ infants. Kenya's new early infant diagnosis guidelines tentatively proposed adding PCR testing at birth, pending results from pilot studies.

METHODS

We piloted birth testing at 4 Kenyan hospitals between November 2017 and November 2018. Eligible HIV-exposed infants were offered both point-of-care and PCR HIV testing at birth (window 0 to <4 weeks) and 6 weeks (window 4-12 weeks). We report the: proportion of infants tested at birth, 6-week, and both birth and 6-week testing; median infant age at results; seropositivity and antiretroviral therapy initiation.

RESULTS

Final sample included 624 mother-infant pairs. Mean maternal age was 30.4 years, 73.2% enrolled during antenatal care and 89.9% had hospital deliveries. Among the 590 mother-infants pairs enrolled before 4 weeks postnatal, 452 (76.6%) completed birth testing before 4 weeks, with 360 (79.6%) testing within 2 weeks, and 178 (39.4%) before hospital discharge (0-2 days). Mothers were notified of birth PCR results at a median infant age of 5.4 weeks. Among all 624 enrolled infants, 575 (92.1%) were tested during the 6-week window; 417 (66.8%) received testing at both birth and 6-weeks; and 207 received incomplete testing (93.3% only 1 PCR and 6.7% no PCR). Four infants were diagnosed with HIV, and 3 infants were initiated on antiretroviral therapy early, before 12 weeks of age.

CONCLUSIONS

Uptake of PCR testing at birth was high and a majority of infants received repeat testing at 6 weeks of age.

Faster Initial Viral Decay in Female Children Living With HIV

Limited data exist regarding sex bias and viral decay in children with HIV. We investigated the sex differences in viral decay in 25 perinatally HIV-infected children. Females presented faster phase I viral decay regardless of their age at antiretroviral therapy (ART) initiation, baseline CD4 percentages, or baseline RNA levels. Also, for each month elapsed under ART, females had faster viral decay than males.

Virologic Response to Very Early HIV Treatment in Neonates

Factors that influence viral response when antiretroviral therapy (ART) is initiated in neonates are not well characterized. We assessed if there is consistency in predictive factors when operationalizing viral response using different methods. Data were collected from a clinical study in South Africa that started ART in neonates within 14 days of birth (2013–2018). Among 61 infants followed for ≥48 weeks after ART initiation, viral response through 72 weeks was defined by three methods: (1) clinical endpoints (virologic success, rebound, and failure); (2) time to viral suppression, i.e., any viral load (VL: copies/mL) <400, <50, or target not detected (TND) using time-to-event methods; and (3) latent class growth analysis (LCGA) to empirically estimate discrete groups with shared patterns of VL trajectories over time. We investigated the following factors: age at ART initiation, sex, birthweight, preterm birth, mode of delivery, breastfeeding, pre-treatment VL and CD4, maternal ART during pregnancy, and maternal VL and CD4 count. ART was initiated 0–48 h of birth among 57.4% of the infants, 48 h–7 days in 29.5% and 8–14 days in 13.1%. By Method 1, infants were categorized into ‘success’ (54.1%), ‘rebound’ (21.3%), and ‘failure’ (24.6%) for viral response. For Method 2, median time to achieving a VL <400, <50, or TND was 58, 123, and 331 days, respectively. For Method 3, infants were categorized into three trajectories: ‘rapid decline’ (29.5%), ‘slow decline’ (47.5%), and ‘persistently high’ (23.0%). All methods found that higher pre-treatment VL, particularly >100,000, was associated with less favorable viral outcomes. No exposure to maternal ART was associated with a better viral response, while a higher maternal VL was associated with less favorable viral response and higher maternal CD4 was associated with better viral response across all three methods. The LCGA method found that infants who initiated ART 8–14 days had less favorable viral response than those who initiated ART earlier. The other two methods trended in a similar direction. Across three methods to operationalize viral response in the context of early infant treatment, findings of factors associated with viral response were largely consistent, including infant pre-treatment VL, maternal VL, and maternal CD4 count.

Quantifying the Dynamics of HIV Decline in Perinatally Infected Neonates on Antiretroviral Therapy

BACKGROUND

Mathematical modeling has provided important insights into HIV infection dynamics in adults undergoing antiretroviral treatment (ART). However, much less is known about the corresponding dynamics in perinatally infected neonates initiating early ART.

SETTING

From 2014 to 2017, HIV viral load (VL) was monitored in 122 perinatally infected infants identified at birth and initiating ART within a median of 2 days. Pretreatment infant and maternal covariates, including CD4 T cell counts and percentages, were also measured.

METHODS

From the initial cohort, 53 infants demonstrated consistent decline and suppressed VL below the detection threshold (20 copies mL) within 1 year. For 43 of these infants with sufficient VL data, we fit a mathematical model describing the loss of short-lived and long-lived infected cells during ART. We then estimated the lifespans of infected cells and the time to viral suppression, and tested for correlations with pretreatment covariates.

RESULTS

Most parameters governing the kinetics of VL decline were consistent with those obtained previously from adults and other infants. However, our estimates of the lifespan of short-lived infected cells were longer than published values. This difference may reflect sparse sampling during the early stages of VL decline, when the loss of short-lived cells is most apparent. In addition, infants with higher pretreatment CD4 percentage or lower pretreatment VL trended toward more rapid viral suppression.

CONCLUSIONS

HIV dynamics in perinatally infected neonates initiating early ART are broadly similar to those observed in other age groups. Accelerated viral suppression is also associated with higher CD4 percentage and lower VL.