Differentiated community-based point-of-care early infant diagnosis to improve HIV diagnosis and ART initiation among infants and young children in Zambia: A quasi-experimental cohort study

Introduction
An estimated 800,000 children (<15 years) globally living with HIV remain undiagnosed. To reach these children with timely HIV testing services during infancy, we implemented a community-based differentiated care model using mobile point-of-care (POC) technology for early infant diagnosis (EID) of HIV, and assessed its effects on EID positivity, antiretroviral therapy (ART) initiation, and 3-month retention in care.

Methods
Between 1 June 1, 2019— and 31 May 31, 2020 at six health facilities in Lusaka, Zambia, we enrolled mother-infant pairs (MIPs) at high risk for vertical transmission of HIV based on missing or late infant EID testing or other maternal risk factors. We offered these MIPs community POC EID testing (post-intervention), and compared their outcomes to historical high-risk controls at the same sites (1 June 1, 2017—–31 May 31, 2018; pre-intervention). We used propensity score matched weighting and mixed effects regression modeling to estimate outcome differences pre-intervention and post-intervention, and to identify MIP characteristics predictive of vertical transmission of HIV.

Results
2,577 MIPs were included in the analysis: 1763 and 814 high-risk MIPs from the pre-intervention and post-intervention periods, respectively. Infant HIV positivity was significantly higher in the post-intervention (2.2%) vs pre-intervention (1.1%) period (pp=0.038), but this difference was attenuated (0.83%, 95% confidence interval [CI]: −0.50%, 2.15%) after adjusting for differences in maternal age, maternal antenatal care visits, infant birth month, and facility. During the post-intervention period, MIPs, where the mother disengaged from care, were 12.97 (95% CI: 2.41, 69.98) times as likely to have an infant diagnosed with HIV vs those in which the infant received late EID testing without maternal care disengagement. Among 18 infants diagnosed with HIV by the intervention, 16 (88.9%) initiated same-day ART and all continued ART at 3-month follow-up.

Conclusion
Community-based differentiated care employing POC EID technology increased testing positivity in unadjusted analyses, and resulted in high ART initiation and early care retention, suggesting it may be a promising approach for reaching infants and young children living with HIV being missed by current facility-based approaches.

Methods
Data collection
All MIPs had the following routine data abstracted from their medical records: demographic information, maternal HIV status, infant HIV testing history, maternal ART history, infant ART history (if relevant), and follow-up visit dates. MIPs in the post-intervention cohort underwent study-specific data collection at enrolment and follow-up on HIV, obstetric, and infant clinical histories, EID testing history, and maternal and infant medication histories. All data were entered into a study database in Microsoft Excel (Redmond, WA, USA) for the pre-intervention period and OpenClinica for all data collected during the post-intervention period.

Study follow-up
Infants who tested as being HIV-positive through the study were followed for 12 weeks past enrollment to observe 3-month retention on ART and to complete a one-time study follow-up visit.