HIV remains one of the biggest public health challenges in sub-Saharan Africa, a region that accounts for approximately two-thirds of about 40 million people living with HIV globally. Young people continue to account for a large share of new infections, with an estimated 370,000 new infections occurring among those aged 15-24 in 2024 alone. This represents approximately 28% of 1.3 million new HIV infections globally the same year. Among them, adolescent girls face a disproportionate risk of infection as girls aged 15-19 are more likely to acquire HIV than their boy peers. HIV testing is the gateway to both prevention and treatment. If someone knows their status, they can start treatment early. Treatment reduces illness and prevents onward transmission. Testing also supports prevention choices, including condom use and pre-exposure prophylaxis.The Joint United Nations Programme on HIV/AIDS (UNAIDS) has set global HIV targets known as the 95-95-95 goals: by 2030, 95% of people living with HIV should know their status; 95% of those diagnosed should be on treatment; and 95% of those on treatment should achieve viral suppression. HIV testing is the critical first step in this cascade, as it determines entry into both treatment and care.We are global public health researchers specialising in maternal, sexual and reproductive health, including HIV prevention and testing, with a particular focus on Africa.We analysed Demographic and Health Survey data from 28 sub-Saharan African countries. The surveys were conducted between 2010 and 2022. Our sample included more than 58,000 adolescent girls and young women aged 15 to 24.Our study looked at whether they had ever tested for HIV. We then examined which social, economic and behavioural factors were linked to testing.Across the 28 countries, 63% of young women reported having tested for HIV. This means more than one in three had never tested. There were also wide variations – between countries as well as between age groups and different social and economic groups.Our findings show that HIV testing among young women in sub-Saharan Africa has increased markedly, from around 13% in the early 2010s to a regional average of 63% in our study. While this may appear encouraging, it masks deep inequalities. In countries like Mali (7%), Chad (14%) and Benin (25%), fewer than half of adolescent girls and young women have ever tested for HIV.This makes it harder to reach global HIV targets. It also means many young women may not know their status. Read more: African countries differ widely in prenatal HIV testing: why it matters A granular understandingZambia recorded the highest testing rate at 76%. Mali recorded the lowest at 6.7%. Three-quarters of the countries had testing coverage below 50% in the 15-24 age group. The findings also reveal clear social gradients. Testing is not equally distributed. It favours those who are older (20-24 years), wealthier, better educated and living in urban areas.This raises concerns about equity. Young women who are poor, less educated, or living in rural areas are more likely to face barriers. These barriers may include cost, distance to health facilities, stigma and lack of information.Comprehensive HIV knowledge stood out as a powerful factor. This means that information and education are central to improving uptake. If young women understand how HIV is transmitted and prevented, they are more likely to seek testing.Pregnancy and union status were also strong predictors. This indicates that contact with health services increases opportunities for testing. But it also suggests that those outside formal health pathways may miss out.The variation between countries shows that policy and programme differences matter. Some countries have achieved higher coverage. Others are lagging behind.The other factors associated with testing we looked at were:Age. Women aged 20 to 24 were much more likely to have tested than those aged 15 to 19. Marital status: Being married or in a union was strongly linked to testing. Pregnancy history was also associated with higher testing. This likely reflects routine HIV testing during antenatal care.Education. Young women with secondary or higher education were more likely to have been tested than those with no schooling. Wealth also played a role. Those from richer households were more likely to have been tested.Knowledge. Young women with comprehensive knowledge about HIV were far more likely to have been tested than those without such knowledge.Sexual behaviour. Those who reported multiple lifetime sexual partners or a recent sexually transmitted infection were more likely to have tested. Employment was associated with slightly higher testing rates.Rural/urban divide: Women living in rural areas were less likely to have been tested compared to those in urban settings. Read more: HIV among older South Africans in rural areas: big study shows there’s a problem that’s being neglected What should be doneFirst, testing services must be tailored to younger adolescents aged 15 to 19. This group consistently had lower testing rates. School-based and community-based programmes can help reach them.Second, efforts should focus on rural and low-income populations. Mobile clinics, community outreach and HIV self-testing kits can reduce access barriers.Third, HIV education must be strengthened. Comprehensive, age-appropriate sexuality education in schools can improve knowledge. Community campaigns can reach out-of-school young women.Fourth, youth-friendly services should be expanded. Clinics need to be welcoming, confidential and non-judgmental. Fear of stigma remains a barrier.Fifth, countries with lower testing rates can learn from those with higher coverage. Sharing best practices, such as integrating HIV testing into other youth services, may help close gaps.Finally, equity must be central to HIV strategies. National averages are not enough. Policymakers should examine who is not testing and why. Data should guide targeted interventions.Adolescent girls and young women are at the heart of the HIV epidemic in sub-Saharan Africa. Ensuring that they know their HIV status is not only a public health priority, it is also a matter of fairness and social justice. Testing is the first step. Without it, prevention and treatment efforts cannot succeed.Obasanjo Bolarinwa is affiliated with York St John University. Sylvester Reuben Okeke, PhD is affiliated with the University of New South Wales, Sydney, Australia