AFJOG

REVIEW African Journal of Obstetrics and Gynaecology | Volume 2 | Issue 3 | 2024 | Pre-Exposure Prophylaxis to prevent HIV infection during Pregnancy and Breast-feeding: A South African Perspective evaluated the VRC01 bNAb and reported a 75% reduction in new HIV infections with strains that were susceptible to the antibodies (92). However, intravenous administration of VRC01 at eight- week intervals over 20 months did not significantly reduce HIV transmission overall. Only 30% of the HIV strains circulating in the regions where the trials were conducted, were sensitive to VRC01. Resistance to VRC01 exhibited by a majority of circulating HIV strains resulted in the inability of this single bNAb to prevent HIV acquisition over time. Among participants who acquired a VRC01-sensitive HIV strain during the trials, the HIV incidence rate was 0.2 per 100 person-years for VRC01 recipients and 0.86 per 100 person-years for placebo recipients. HIVVACCINE/PREPCOMBINATIONS Vaccines administered alongwith PrEP have been evaluated. The PrEPVacc is an African-led, European-supported HIV prevention study conducted in ESA countries from 2018 to 2024 (93) . This was the first HIV vaccine efficacy trial to be funded outside the United States of America. The study evaluated the effectiveness of a DNA, MVA and protein based (HIV-DNA-env) or a DNA and protein based (DNA-env) HIV vaccine administered together with oral PrEP (TDF/FTC or F/TAF). In July 2024, PrEPVacc reported the results of the HIV vaccine arm, which showed conclusively that neither of the two experimental vaccine regimens prevented HIV acquisition. The oral PrEP arm of the study is still on-going. VACCINESDURINGPREGNANCYANDBREASTFEEDING Only a limited number of vaccines have been shown to be safe in pregnant and lactating women, as vaccine trials have generally excluded this population group (94) . Women who plan pregnancy and participating in vaccine trials are required to postpone it. Routine pregnancy tests are done as part of the screening process and before each scheduled immunization. Participating women of childbearing age must agree to an adequate method of birth control prior to and during the immunization period of a trial. Approximately 193 pregnancies have been reported from the HIV Vaccine Trial Network (HVTN) (95) . The overall pregnancy rate was 3.15 per 100 woman-years. While active contraception use was required during study participation, 13 of 53 studies also contained a long-term follow-up period, during which pregnancy was no longer discouraged. Adverse events are yet to be reported (96) . Novel technologies for the development of vaccines may change this narrative. The COVID-19 messenger-RNA (m-RNA) vaccine has been shown to be safe for pregnant women and infants (96) . The manufacturing of m-RNA vaccines does not require cell culture and the turnaround is swift. This is a field that certainly needs further investigation in the prevention of HIV acquisition. The HVTN 302 trial is a proof-of-concept study initiated in 2022, evaluating the safety and effectiveness of three experimental mRNA HIV vaccines (97) . Preliminary results have reported mild to moderate skin reactions in 7% - 18% of participants, that were managed with simple anti-histaminic agents. There were no serious adverse events reported (98) . Box 9 illustrates the state of PrEP options in the context of PBFW. Box 9: HIV Prevention Research in Relation to Pregnancy and Lactation CONCLUSION Great strides have been made in controlling the HIV pandemic over the past 2 decades. More than 6 million individuals are estimated to have initiated PrEP since the first approval of Truvada in 2012 (99) . Despite these achievements, perinatal transmissions of HIV continue to be reported worldwide. Astonishingly, more than 180 000 infants were reported to have been infectedwithHIV in 2017 (100) . The greatest risk of perinatal transmission has been reported to occur during breastfeeding, in resource-limited settings (15) . This underscores the need for the prioritization of AGYW and PBFW for PrEP. Goals set out in the 2022–2030 Global Health Sector Strategies on HIV, Viral Hepatitis, and Sexually Transmitted Infections recognize the implementation of PrEP services as a global key action (101) , in an attempt to eradicate new HIV infections by 2030. WHO recommends a differentiated PrEP service delivery approach that is person-centred, community-oriented and adapts services to the needs of target populations, to bolster intake and retention in care (6) . The eradication of new HIV infections, will overtime, result in the elimination of perinatal HIV transmissions. Lack of awareness and demand for pre-exposure prophylaxis is of great concern (102) . An antenatal survey conducted in South Africa in 2022 reported 31.2% of HIV-uninfected women to be eligible for PrEP (8) . Of this number, only 3.6 % were on PrEP prior to pregnancy. Pre-exposure prophylaxis coverage was found to be lower in younger women (15-19yrs), relative to older women (35-49yrs) (8) . Enhancing retention in care of individuals on PrEP is key to the prevention of new HIV infections. South Africa has successfully integrated its PMTCT programme into paediatric care services during the postpartum period, to reduce the likelihood of disengagement from care (15) . Researchers, clinicians, funders, and civil society must come together to share knowledge, expertise and resources in order to achieve a common goal. Stakeholder engagement is critical, in scaling-up the implementation of HIV prevention programs in low-middle income countries and in the development of national guidelines. Regulatory approval of novel formulations such as DVR and LEN must be prioritized, especially for adolescent girls below 18 years of age. Research gaps still exist on the prevention of HIV acquisition, especially among PBFW. More complete evidence on the safety of exposure in different trimesters and for extended periods is required, to guide the development of effective guidelines. Pregnant and breastfeeding women are a particularly important African Journal of Obstetrics and Gynaecology | Volume 2 | Issue 3 | 2024 | 13