“It's exactly what's needed”: a call to action for breastmilk studies of vertical HIV transmission in high-income countries

This is the authors' abstract. We don't add key points for this paper.

Increasing numbers of parents living with HIV in England and the United Kingdom choose to breastfeed their infants, yet guidelines for high-income countries (HICs) still recommend exclusive formula feeding to eliminate all risk of vertical transmission. The risk of HIV transmission through breastmilk is less than 1% when the feeding parent is virally suppressed on antiretroviral therapy. However, this data comes from studies conducted in low- and middle-income countries limiting their generalisability to contexts where parents are more likely to be virally suppressed on long-term antiretroviral therapy with access to regular viral load monitoring. The risk of HIV transmission through breastfeeding in the context of long-term pre-pregnancy HIV viral suppression is largely understood through indirect observational studies in HICs, suggesting the risk of HIV transmission may be lower than currently understood. We may be providing parents living with HIV in high income countries with infant feeding guidance that does not adequately reflect their level of risk. In this perspective paper, we explore the reasons behind the paucity of large-scale microbiological lactational research in this population group. We also present brief findings from the NOURISH-UK study which explored experiences of infant feeding decisions among UK-based mothers living with HIV: our participants expressed frustration about the lack of evidence applicable to their situation and were universally enthusiastic about donating breastmilk samples to enable research to take place. We deliver a call to action to researchers, clinicians, research funders and clinical networks to explore the logistics and practicalities of how this work could be supported.