In 2024, about 98,000 newborns in sub-Saharan Africa were born with HIV. Almost half of these cases are linked to a lack of access to ART among women living with HIV, and 20% to discontinuation of treatment during pregnancy or breastfeeding. However, another quarter of children with HIV were born to mothers who acquired HIV during pregnancy or the breastfeeding period. In countries such as South Africa and Zambia, this route of transmission accounts for almost 60% and 50% of cases respectively. Lenacapavir, administered as an injection once every six months, has shown high efficacy in clinical trials and could become a solution for women facing an increased risk of acquiring HIV precisely during these vulnerable periods. The advantage of the injectable form is that it removes the barrier of having to take pills daily, which is especially significant during pregnancy and infant care.
Anna Yakusik and her colleagues from UNAIDS built a mathematical model estimating the use of lenacapavir among HIV-negative pregnant and breastfeeding women over 2.2 years — from the first antenatal visit to the end of breastfeeding. The baseline scenario assumed 65% coverage and 70% retention on therapy. The cost of the drug was calculated based on the projected generic price of $40 per person per year; the service cost was $50 per person per year, by analogy with oral PrEP programs. The researchers tested two approaches: universal rollout for all HIV-negative pregnant and breastfeeding women aged 15–49 in sub-Saharan countries, and geographically targeted rollout in regions with the highest incidence.
The universal baseline scenario covered 25.5 million women and prevented 56,000 HIV transmissions — 44,500 among mothers and 11,600 among infants — at a total program cost of $5 billion. After deducting lifelong savings on ART, the net cost was $85,000 per transmission prevented. A completely different picture emerged with the targeted approach in the highest-priority regions (mainly South Africa, Mozambique, Zambia, and Eswatini): the baseline scenario covered about 626,000 women and prevented 8,500 transmissions at a program cost of $126 million — a net cost of $8,500 per transmission prevented. The most selective approach consistently yielded the lowest cost per case prevented.
Retention on therapy turned out to be the most important factor determining cost-effectiveness. Under the highest-priority strategy, the net cost per HIV transmission prevented ranged from $4,800 in the most favorable scenario (90% retention, $35 service cost) to $15,100 in the least favorable (50% retention, $75 service cost). The level of coverage did not significantly affect cost-effectiveness, since expanding coverage simultaneously increased both the number of women receiving prophylaxis and the costs.
The researchers state unequivocally that lenacapavir should be considered a complement to, not a replacement for, existing programs to prevent vertical HIV transmission. Most such cases still occur because of insufficient HIV testing coverage, delayed initiation of ART, and mothers dropping out of treatment. For people living with HIV, these data are doubly important: reducing new infections among women of reproductive age lowers the overall burden of the epidemic, and the model is a reminder of the critical importance of retention on ART during pregnancy and breastfeeding. Your own undetectable viral load is the guarantee that a child will be born without HIV, regardless of the availability of injectable PrEP.