Chiva Conference: Global Perspectives and UK Experiences of Preventing Vertical HIV Transmission
The 19th Annual Chiva Conference on Friday 4 April had a key theme around preventing vertical HIV transmission, with an emphasis on infant feeding.
Georgina Fernandes (UCL Great Ormond Street Institute of Child Health) presented a global perspective.
Globally, paediatric HIV infections have dropped by over 77% but still fall short of UNAIDS targets. A major factor is limited access to maternal antiretroviral therapy (ART), which has stagnated at 84% coverage. Recent cuts to PEPFAR and USAID threaten these fragile gains.
In Europe, vertical transmission rates are low, though prevention strategies vary across countries. An online PENTA survey of clinical teams in 16 out of 20 high-income countries revealed that all but Latvia had national guidelines, but differed in risk categorisation, infant PEP protocols, and breastfeeding recommendations. Only half of the countries supported breastfeeding under specific conditions. Due to the lack of evidence (from randomised controlled trials), risk stratification and guidance on prescribing infant prophylaxis guidelines varied significantly. The length of time babies are given infant prophylaxis also varied (two to six weeks).
Georgina concluded by calling for greater harmonisation in clinical monitoring and management across Europe (and other high-income countries) to ensure effective prevention while avoiding unnecessary drug exposure for infants.
Prof. Hermione Lyall (Imperial College Healthcare) followed with insights from the UK around infant feeding. While breast/chestfeeding is supported under certain conditions – such as maintaining an undetectable viral load -only formula feeding eliminates all risk of HIV transmission. Though rare, there have been documented cases of transmission during breastfeeding, even when the parent was undetectable (PROMISE and DOLPHIN studies).
Without any intervention, around one in three babies born to mothers with HIV would acquire the virus. However, with near-universal screening for HIV, syphilis, and hepatitis B, plus access to antiretroviral therapy (ART), the UK now has one of the world’s lowest rates of vertical transmission (0.22%). Between 2018–2019, only 3 of 1,205 babies born to mothers with HIV acquired the virus. Most women with HIV in the UK know their status before pregnancy, and nearly 90% are on ART at conception. Demographic shifts include an increase in older mothers, more women from Eastern Europe, and a decrease in women of African descent. Women with vertically acquired HIV tend to be younger, averaging 24 years, compared to 34 years for all pregnant women with HIV.
The upcoming 2025 BHIVA infant feeding guidelines, will recommend open discussions about feeding choices by the second trimester, emphasising that only formula feeding is risk-free.
In the UK, those who breastfeed typically do so for an average of seven weeks, ranging from one day to two years. Across the UK, Switzerland, Germany, and the USA, no transmissions have been reported during breastfeeding while undetectable – but data is limited. Prof. Lyall concluded with a powerful interview from a mother who had chosen to breastfeed – herself once a baby in Lyall’s care – highlighting both the emotional and practical complexities of that decision.
The session ended with a discussion on modeling risk and using data from middle-income countries (with reliable viral load testing) to evidence the transmission risk when breastfeeding while undetectable. Because breastfeeding carries more exposure risk than sex (due to factors like mastitis, infant gut issues and due to more fluid exposure), more data – potentially from thousands of mother/birthing parent and baby cases – are needed to fully assess risk.
Critical Reviewer: Bakita Kasadha, NIHR Doctoral Research Fellow, University of Oxford
