• clinical ethics

In many regions around the world, those at highest risk for acquiring HIV are young adults and adolescents. Young men who have sex with men (young MSM) in the USA are the group at greatest risk for HIV acquisition, particularly if they are part of a racial or ethnic minority group.1 Adolescent girls and young women have the highest incidence rates of any demographic subgroup in sub-Saharan Africa.2 To reverse the global AIDS pandemic’s toll on these high-risk groups, it is important to deploy the most effective HIV prevention tools to young MSM in the USA, to adolescent girls and young women in sub-Saharan Africa, and to any other adolescents and young adults at high risk for HIV as products are proven to be safe and efficacious. Although prevention interventions with proven efficacy, such as oral pre-exposure prophylaxis (PrEP), are available,3–8 they have not been sufficient to stem the tide and an expanded prevention toolkit is urgently needed to serve these populations. The field of HIV prevention continues to identify promising leads in the development of new biomedical prevention products, either delivering antiviral drug topically (eg, the dapivirine vaginal ring) or systemically (eg, injectable cabotegravir). The dapivirine ring has been shown to provide modest protection and is currently being tested in open label studies while injectable cabotegravir is being tested in a large efficacy trial for preventing HIV acquisition. Advances in the field of HIV prevention mean that scientists and regulators must plan for how they will bring prevention tools to populations at high risk for HIV as they conduct efficacy and effectiveness trials. For instance, safety data from younger age groups can also be used in combination with efficacy data from adult studies, where appropriate, as bridging studies to expand labelling to younger ages. If these …