HIV transmission and retention in care among HIV-exposed children enrolled in Malawi's prevention of mother-to-child transmission programme

Abstract

Introduction: In Malawi, HIV-infected pregnant and breastfeeding women are offered lifelong antiretroviral therapy (ART) regardless of CD4 count or clinical stage (Option B+). Their HIV-exposed children are enrolled in the national prevention of mother-to-child transmission (PMTCT) programme, but many are lost to follow-up. We estimated the cumulative incidence of vertical HIV transmission, taking loss to follow-up into account.

Methods: We abstracted data from HIV-exposed children enrolled into care between September 2011 and June 2014 from patient records at 21 health facilities in central and southern Malawi. We used competing risk models to estimate the probability of loss to follow-up, death, ART initiation and discharge, and used pooled logistic regression and inverse probability of censoring weighting to estimate the vertical HIV transmission risk.

Results: A total of 11,285 children were included; 9285 (82%) were born to women who initiated ART during pregnancy. At age 30 months, an estimated 57.9% (95% CI 56.6-59.2) of children were lost to follow-up, 0.8% (0.6-1.0) had died, 2.6% (2.3-3.0) initiated ART, 36.5% (35.2-37.9) were discharged HIV-negative and 2.2% (1.5-2.8) continued follow-up. We estimated that 5.3% (95% CI 4.7-5.9) of the children who enrolled were HIV-infected by the age of 30 months, but only about half of these children (2.6%; 95% CI 2.3-2.9) were diagnosed.

Conclusions: Confirmed mother-to-child transmission rates were low, but due to poor retention only about half of HIV-infected children were diagnosed. Tracing of children lost to follow-up and HIV testing in outpatient clinics should be scaled up to ensure that all HIV-positive children have access to early ART.

Keywords: Option B+; Prevention of mother-to-child transmission (PMTCT); retention.

Figure 1.

Flow chart of eligibility of study participants.

Figure 2.

Multi-state model. The boxes represent the six states of the multi-state model and the black triangles represent the events that trigger transitions between states. All children start in State 1 “not yet enrolled” when they are born, and switch to State 2 “retained in care” after they enrolled into HIV care. Children remain in State 2 until they were discharged HIV-negative (State 3), lost to follow-up (State 4), initiated ART (State 5) or died (State 6), or else, until their follow-up ended. States 3 to 6 are absorbing states (i.e. children who have entered an absorbing state remain in this state).

Figure 3.

Unweighted and weighed cumulative incidence of HIV infection in HIV-exposed children. Estimates of the cumulative incidence of HIV infection among all children enrolled into care from unweighted and weighted analyses. The weighted analyses correct for unobserved test results in children lost to follow-up or not tested Shaded areas show 95% confidence intervals.

Figure 4.

Percentages of HIV-exposed children not yet enrolled, retained in care, discharged HIV-negative, lost to follow-up, initiated ART or dead. The coloured areas show the percentage of children in the corresponding state at the given time. Children were discharged confirmed HIV-free if they were tested HIV-negative at least 6 weeks after cease of breastfeeding. Children were considered lost to follow-up if they had missed a clinic appointment for more than 60 days and did not return to care thereafter.

Figure 5.

Percentages not yet enrolled, retained in care, discharged HIV-negative, lost to follow-up, initiated ART or dead among HIV-exposed children at low and at high risk of mother-to-child transmission. Figure (a) (low-risk profile) shows HIV care outcomes for children who received nevirapine prophylaxis at and after birth and who were born to women who received antiretroviral therapy (ART) during and after pregnancy. Figure (b) (high-risk profile) shows HIV care outcomes of children who received no nevirapine prophylaxis and were born to women who were not on ART.