Incident HIV acquisition among pregnant women in Botswana: findings from the Tsepamo birth outcomes surveillance study.

INTRODUCTION: In Botswana, where almost all pregnant women known to have HIV receive antiretroviral therapy, a large proportion of vertical HIV transmission may occur among women with incident undiagnosed HIV infection during pregnancy. Botswana guidelines recommend repeat HIV testing every 3 months in pregnancy, with at least one test in the third trimester. We evaluated the rate of repeat HIV testing, calculated HIV incidence during pregnancy and estimated missed seroconversions. METHODS: In the Botswana Tsepamo Study, we abstracted HIV test dates and results from obstetric records of all women who delivered at maternity wards in 18 communities between 7th May 2017 and 20th August 2021. We defined seroconversion as an initial negative/indeterminate HIV test in pregnancy followed by a positive test during pregnancy/at delivery. The incidence rate (IR) of seroconversion was calculated among women with > = 2 known test dates. Missed seroconversions were estimated among women without a test in the third trimester by applying the IR to the time after the last HIV test until delivery. RESULTS: Among 103,529 women delivering in the study period testing negative at the first test and with known conception and HIV test dates, 29,085 (28%) were tested in one trimester of pregnancy, 73,156 (71%) were tested in ≥ 2 trimesters of pregnancy and 9628 (9%) had a test in all trimesters. A total of 78,162 (75%) women had a third-trimester test. There were 223 seroconversions (2.58/1000 pregnancies, 0.26%) among those with ≥ 2 known HIV test dates, yielding an IR of 0.69/100 person-years. Among 25,289 women who did not have a test in the third trimester, we estimate approximately 58 seroconversions may have been missed during pregnancy due to a lack of repeat testing. Factors associated with seroconversion during pregnancy included younger age, less education and not being married. CONCLUSIONS: More than two-thirds of women had repeat HIV testing in pregnancy and HIV incidence was low. However, an estimated 21% of seroconversions in pregnancy were likely missed due to a lack of re-testing. To reach the goal of zero new paediatric HIV infections, Botswana will need to intensify repeat HIV testing in the third trimester of pregnancy.

Lack of HIV RNA test result is a barrier to breastfeeding among women living with HIV in Botswana.

BACKGROUND: Botswana updated its antiretroviral treatment (ART) guidelines in May 2016 to support breastfeeding for women living with HIV (WLHIV) on ART who have documented HIV RNA suppression during pregnancy. METHODS: From September 2016 to March 2019, we evaluated feeding method at discharge among WLHIV at eight government maternity wards in Botswana within the Tsepamo Study. We validated the recorded feeding method on the obstetric record using the prevention of mother-to-child transmission of HIV (PMTCT) counsellor report, infant formula dispensing log or through direct observation. Available HIV RNA results were recorded from the obstetric record, and from outpatient HIV records (starting February 2018). In a subset of participants, we used electronic laboratory records to verify whether an HIV RNA test had occurred. Univariable and multivariable logistic regression analyses were performed to identify factors associated with infant feeding choice. RESULTS: Among 13,354 WLHIV who had a validated feeding method at discharge, 5303 (39.7%) chose to breastfeed and 8051 (60.3%) chose to formula feed. Women who had a documented HIV RNA result in the obstetric record available to healthcare providers at delivery were more likely to breastfeed (50.8%) compared to women who did not have a documented HIV RNA result (35.4%) (aOR 0.59; 95% CI 0.54, 0.65). Among women with documented HIV RNA, 2711 (94.6%) were virally suppressed (< 400 copies/mL). Breastfeeding occurred in a substantial proportion of women who did not meet criteria, including 46 (30.1%) of 153 women with HIV RNA > 400 copies/mL, and 134 (27.4%) of 489 women with no reported ART use. A sub-analysis of electronic laboratory records among 150 women without a recorded result on the obstetric record revealed that 93 (62%) women had an HIV RNA test during pregnancy. CONCLUSIONS: In a setting of long-standing use of suppressive ART, with majority of WLHIV on ART from the time of conception, requiring documentation of HIV RNA suppression in the obstetric record to inform infant feeding decisions is a barrier to breastfeeding but unlikely to prevent a substantial amount of HIV transmission.