Habits surrounding HIV prevention, such as finding an appropriate prevention method, or being aware of vulnerabilities that make one susceptible to HIV, are seldom consistent or widespread among at-risk populations. One of the factors influencing this is the relevance of HIV prevention to the individual. HIV prevention has been observed to be a low priority among adolescent girls and young women, and among men who have sex with men, who may instead prioritize economic needs and opportunities, safety from violence, and managing their familial and social relationships ^{8, 9} . Furthermore, a dominant mental model that one seeks medical help only when sick limits the relevance of prevention preparedness, as studies from Malawi and Rwanda among female sex workers and men who have sex with men have shown ^{10, 11} . Strategies to make HIV prevention relevant include integrating HIV prevention services into other health services ¹² , and showing how HIV prevention serves other life goals: for example, women who have higher-order, long-term goals to become pregnant have been found more likely to adhere to oral pre-exposure prophylaxis (PrEP) ¹³ .

Prevention action is also impacted by limited risk saliency, meaning that preventing HIV may not be top-of-mind when people are making decisions about sexual behavior (for example, because a potential partner shows no symptoms of HIV, or the individual believes that HIV is a manageable disease, or they have more pressing priorities than HIV prevention). Respondents in studies in South Africa, Kenya and Nigeria were optimistic that they would not get infected with HIV, and continued to engage in risky sexual behavior ^{14– 16} . Limited risk saliency is also influenced by present bias – the tendency to prioritize perceived short-term gains at the cost of long-term outcomes ¹⁷ .

Social norms also contribute to a suboptimal risk assessment. Young people find little or low concern for safety around HIV among their peers, and this can negatively affect their own risk perception ¹⁸ . Particularly among men, stereotypes surrounding masculinity drive emotional suppression that can hinder information-seeking and support, thus affecting adequate assessment of HIV risks ¹⁹ . For adolescent girls and young women and female sex workers, harmful gender norms lead to a discounting of the risk originating from gender-based violence, even though this places individuals at higher risk of HIV ²⁰ .

Another factor is that individuals generally take in HIV messages at times when they are not engaging in sexual behavior. In this “cold” state, deliberation on risks and benefits is optimally rational. But settings where unsafe risky behaviors take place often do not allow for optimal rational evaluation of risks and benefits. In this emotionally activated “hot” state, heuristics (mental short-cuts) are used for risk assessment. HIV prevention programs for adolescent girls and young women and men who have sex with men generally take place in out-of-context and safe (i.e. “cold state”) settings ¹⁷ , but this may not equip them to perceive and accurately evaluate HIV risk at the time of sexual contact.

Individuals may experience discomfort, fear and anxiety while exploring HIV prevention options. An inability to cope with these negative emotions impacts the uptake of prevention products and services. Fear of stigmatization is a significant barrier. In sub-Saharan Africa, fear of disclosing test results was driven by normative expectations of social ostracization and partner abandonment, leading to avoidance of healthcare facilities and affecting uptake of HIV testing ^{21– 24} . These fears are disproportionately experienced by key populations ^{25, 26} .

Similar reactions have also been associated with PrEP, which is often conflated in popular perception with ART, meaning that a person who is taking PrEP for HIV prevention may be mistakenly perceived as already infected with HIV. Men who have sex with men and young people, including adolescent girls and young women in Uganda, Zimbabwe, and South Africa, often encounter negative attitudes when seen to be using PrEP and are subjected to stigmatization ^{27, 28} . For female sex workers, using HIV prevention products can signal that they are sex workers, leading to potential police harassment and social ostracization ²⁹ . A review of studies found that adolescent girls and young women’s uptake of condoms is affected by a fear that if they ask their partners to use a condom, they will themselves be judged as promiscuous and unfaithful ²⁶ .

Fear of disruption in normal life and the perceived impact upon one’s sex life affect an individual’s decisions around prevention. In South Africa, Nigeria, Kenya, and Zambia, condom use was associated with loss of pleasure due to the absence of “skin-to-skin” contact during protected sex ^{30– 32} .

Fear of side-effects is a critical influencing factor. Pregnant women, men who have sex with men and transgender women in South Africa most frequently cited side-effects as the reason for stopping their use of PrEP during a one-year course, even though the side-effects monitored in the study were small ^{33– 35} . In a qualitative study of adolescent girls and young women in Uganda, side-effects were also the main reason reported for stopping PrEP after 6 months of use ³⁶ . For the dapivirine vaginal ring (DVR, a silicone ring inserted in the vagina that releases an antiretroviral drug over a four-week period), perceived ring interference with sex, menstrual cycles, or potential harm to the vaginal environment have been expressed as concerns ³⁷ . Coping potential is also inadequate when it comes to anticipated pain. Corroborating a meta-analysis of the uptake of CAB-LA (a long-lasting injectable HIV prevention drug), a study conducted in Cape Town found that fear of the pain of injections impacted treatment uptake ^{38, 39} .

mHealth interventions in Ghana and South Africa, have helped reduce the stigma and anticipated discrimination associated with in-person testing, and signing confidentiality agreements has helped enhance patient satisfaction and trust within clinics ^{40, 41} . The confidentiality of HIV self-testing (HIVST), and control over PrEP use, are further enablers that combat fear of judgement. HIVST alleviates issues around lack of privacy and trustworthiness of providers ⁴² . The provision of channels for HIVST other than physical stores has also shown success at improving self-testing, such as the rollout of self-screening at Central Chronic Medicines Dispensing and Distribution points (CCMDD) in South Africa ⁴³ . Community-focused interventions have helped promote effective use of PrEP, condoms, and HIV testing. These primarily seek to raise community awareness to help reduce stigma, along with peer support and educators who help the individual conduct HIVST or cope with taking PrEP ^{44– 46} .

DVR could help address barriers to adherence seen with oral PrEP since it does not require regular daily uptake thus reducing fear of stigma ⁴⁷ . Early trials have found that DVR has been well tolerated by women, side-effects are low, and adherence and reported desire for continued use is high ^{48– 50} . When given a choice between oral PrEP and DVR, two-thirds of adolescent girls and young women in the REACH program in South Africa, Zimbabwe, and Uganda chose DVR ⁵¹ .

Though there has been considerable success in improving the range of choice when it comes to HIV prevention, exercising effective choice has not progressed at the same pace. Lack of individual agency, a sense of control, to negotiate use of HIV prevention products and services remains a significant barrier. Agency is affected by factors such as gender norms, violence, and mental health.

Women may be at risk of violence from sexual partners and have little power to negotiate the use of condoms. Female sex workers in South Africa and Ethiopia report a tradeoff between asking a client to use a condom during sex and remaining safe from violence from the client, in which they will prioritize their immediate safety ^{52– 54} . Adolescent girls and young women across sub-Saharan Africa who may face violence or be unable to safely ensure condom use during sex have therefore expressed greater interest in PrEP to protect themselves from HIV ^{55, 56} . Engaging partners in HIV prevention can improve risk evaluation within relationships. In the case of stable older relationships, partner engagement has improved last reported use of condom and led to a reduction in self-reported violence ⁵⁷ .

Poor mental health or inebriation may also reduce the ability to engage in prevention decision-making. Depression has been associated with lower adherence to PrEP and to ART ⁵⁸ . Women in East Africa, South Africa, Kenya, and Uganda who were depressed had lower adherence to PrEP ^{59, 60} , but depression did not impact PrEP adherence among men in East Africa or women in Uganda ^{58, 59} .

Interactions involving communication campaigns, and service delivery by providers, face several challenges, one of which is that at-risk populations are often subjected to a blanket approach, be it in product promotion or behavior change communications. This leads to non-alignment of HIV prevention with the precise identities and needs of users. For instance, messaging aimed broadly at men who have sex with men might not resonate with men who identify specifically as gay, and communication targeting an adolescent girl might not be relevant to a young woman ⁶¹ . This mismatch between identities and communication content can increase avoidance of product communication messages and further isolate individuals from seeking appropriate HIV prevention opportunities. Communication on HIV prevention and risk also often does not consider how identities can shift within the same individual, e.g. HIV-negative to HIV-positive, or from not being pregnant to being pregnant ⁶² . Each of these identities carry with it a different set of needs and vulnerabilities, which if not addressed or considered can lead to individuals being unable to appreciate their level of risk.

Interactions between user and providers are also hampered by service-related limitations such as product availability, facility hours, and staff shortages. A notable barrier at this level is low product availability. As of 2020, there was a shortage of 3.3 billion condoms distributed in eastern and southern Africa ⁶³ , and PrEP was only widely available in five countries’ national public health systems in the sub-region ⁶⁴ . In South Africa, provincial-level departments of health experience frequent shortages in PrEP supplies, which is a substantial barrier for uptake among pregnant and postpartum women in Cape Town ^{34, 65} . A lack of testing kits has also been seen across sub-Saharan Africa ²³ .

Key populations have varying needs and barriers when it comes to accessing and using prevention methods such as PrEP, condoms, and HIV testing, and current service delivery models may therefore not work for all of them. Differentiated service delivery (DSD) has been successful in adapting service delivery to the differentiated needs and vulnerabilities of the individuals being served, such as through fast-tracked collection of HIV medication, community pick-up points or home delivery, multi-month dispensing and frequent refill options, as well as adherence support groups and extended clinic hours ^{66– 70} . DSD has primarily been used to promote ART adherence, but there is a growing focus on the need and opportunity to expand this to other prevention services such as PrEP and HIV testing where barriers to access remain pressing ⁷¹ .

A recent shift in DSD is toward integration of services ^{12, 72, 73} . HIV can be integrated with services for non-communicable diseases and TB, as well as for STI testing, family planning, and gender-affirming hormone therapy ^{74, 75} . For example, PrEP is being integrated into family planning services, antenatal clinics, and post-abortion care services in Kenya ⁷⁴ . Other health services can also be integrated into existing HIV services, such as offering hypertension and diabetes management at ART adherence clubs ⁷⁶ . There is an opportunity for greater integration of HIV services and mental health, especially given that vulnerabilities such as depression and substance use impact HIV prevention adherence, although there is currently little evidence of integration in this area.

Service integration as part of policy, as well as program design, can support both DSD as well as combination prevention, i.e. the combining of biomedical, behavioral, and structural interventions ⁷⁷ . This may be especially important for improving service delivery for key populations, as they face complex and varied barriers such as legal limitations, social stigma and provider bias, gender-based violence and social and economic inequalities ^{77, 78} . An analysis of studies to promote condom use among female sex workers in sub-Saharan Africa found that combination prevention was highly effective. Effective interventions included educating female sex workers and creating supportive work environments, while others involved peer support combined with free condoms provided through peers as well as health providers ⁷⁹ .

Health systems and programs have found it difficult to involve crucial stakeholders like family and religious leaders in HIV communication efforts because of prevailing social norms stigmatizing key populations. The inability to appeal to the strong ties of family and religion often prevents programs and providers from leveraging credible, trustworthy sources of information and support in outreach to key populations.

Healthcare providers are often biased against key populations and are sometimes ignorant of their obligation to maintain the confidentiality of their patients ⁸⁰ . A study in Ghana found providers preaching religious teachings to men who have sex with men seeking treatment, and sometimes outright ignoring them ⁸¹ . Negative attitudes among healthcare providers in South Africa hinder the promotion and delivery of PrEP to young people ⁸² . Other studies in sub-Saharan Africa have also highlighted how provider bias obstructs treatment access for young people, including adolescent girls and young women, who are subjected to unnecessary and demeaning conditions, impeding their reproductive health choices ^{83– 85} .

One way to enable more open and stigma-free interactions between key populations and healthcare providers is sensitivity training to help providers better understand the behaviors and needs of key populations ⁷⁴ . Kenya and Zimbabwe’s national policies suggest the use of the “train the trainer” model, in which healthcare providers train other providers, creating a snowball effect and speeding up the de-stigmatization of healthcare settings ⁸⁶ . In Kenya, men who have sex with men who are HIV+ being engaged through culturally trained peer educators have improved willingness to be engaged in treatment ⁸⁷ . Studies in Tanzania and Uganda showed that uptake of HIV prevention strategies rose to almost 70% when endorsed by religious leaders ^{88, 89} . Support groups and peer educators and mentors have been seen to improve PrEP adherence for female sex workers, adolescent girls and young women, and men who have sex with men in Kenya ^{64, 90} .

One approach to engaging individuals about HIV prevention is to involve key stakeholders within their ecosystem, including peers, partners, support groups, etc. The “enhanced peer outreach approach” capitalizes on key population individuals’ higher trust in their peers, leading to better engagement with HIV awareness programs, promoting safer sexual practices and increasing the probability that the individual attains the desired risk perception ^{91– 93} . However, only limited studies have been done to show if peer led outreach impacts risk perception enough to alter risky sexual behaviors.

Women visiting antenatal and postpartum care in Kenya, Malawi, and Uganda have been given HIVST kits to share with their partners, which has improved testing uptake among these men ^{94, 95} . Community-led monitoring and peer support has also shown to promote HIVST ⁴⁶ .

Another ecosystem-rooted engagement approach aims to engage men/partners in addressing vulnerabilities resulting from partner violence and harmful gender norms. Inequitable gender norms negatively impact women’s access to care, levels of physical and sexual violence and condom use. In stable relationships among older couples, male-partner engagement has improved the reported use of a condom on the most recent occasion of sex, and led to a reduction in self-reported violence ⁵⁷ . In Kenya, the “better family” intervention using couples counselling on HIV testing and care showed positive couple communication and efficacy to act around HIV ⁹⁶ . For adolescent girls and young women, school-based programs on HIV and violence reduction have shown positive results in terms of reduced acceptability to partner violence and decrease in multiple partners ⁹⁷ .

Support groups and peer educators and mentors have improved PrEP adherence for female sex workers, adolescent girls and young women, and men who have sex with men in Kenya ^{64, 90} . DSD interventions that focus on flexible adherence support and enable more frequent visits may be particularly beneficial for adolescent girls and young women ⁹⁸ . There is also the potential to integrate social media into these services, such as the use of WhatsApp© chat groups for adherence clubs ⁹⁹ .

It can be important to differentiate between the communication preferences of different groups. A study in Nigeria showed that that female sex workers preferred face-to-face interactions, phone calls, and SMS for information regarding PrEP and HIVST, while men who have sex with men preferred digital platforms like WhatsApp, Facebook©, Instagram©, and Twitter© ¹⁰⁰ .

Structural barriers lead to inadequate access to healthcare services for key populations, and insensitive service delivery. Laws criminalizing the identity or behaviors of key populations constitute a key barrier ⁸⁷ . A constraining legal environment leads to fear of – and actual – violence and harassment. This is evident for example in countries like Cameroon, Uganda, Nigeria, and Malawi, where criminalization limits the involvement of key populations in HIV prevention campaigns and access ^{101– 104} . Criminalizing sex work obstructs HIV prevention efforts, subjects sex workers to police harassment and sexual violence ^{105, 106} , and undermines safe-sex negotiations with clients ¹⁰⁷ . Similarly, laws penalizing same-sex relationships contribute to stigma and discrimination, and hinder HIV prevention interventions, perpetuating the epidemic among men who have sex with men ¹⁰⁸ . Countries that have decriminalized same-sex relations, such as South Africa and Botswana, have seen greater rates of testing and access to treatment among men who have sex with men ⁷⁸ .

Sex workers in China and Uganda must avoid accepting condoms from health services due to concerns that condoms will be used as evidence of sex workers’ occupation, which is illegal and can lead to imprisonment or even the death penalty ^{109, 110} . Studies conducted in Ethiopia, Kenya, China, and India found evidence of violence by law enforcement against sex workers, with police demanding condomless sex. However, most of the evidence towards working on mitigating violence from law enforcement has been concentrated in community-led interventions and mobilization of female sex workers and men who have sex with men to take legal action ¹⁰⁶ . There has been limited evidence of state-level policy interventions acknowledging the existence of violence and prohibiting its perpetration on female sex workers and men who have sex with men ^{111– 113} .

Strict consent laws for medical services in countries like Uganda and Kenya make it difficult for adolescents to access prevention until they are 18. This is particularly worrying for adolescent girls and young women at heightened risk of HIV, since the only way to access treatment is through explicit consent from their parents or guardians, which can lead to violence and social ostracization ¹¹⁴ . However, several countries are making strides in addressing consent laws. South Africa’s reduction in the age of consent for medical services to 12 years saw significant increases in uptake of PrEP and HIV testing among teenagers ¹¹⁵ . Tanzania also achieved comparable results after lowering the age to 12 ¹¹⁴ .

Harmful gender norms make it difficult, especially for women, to exercise choice and agency to assess and access relevant HIV prevention opportunities. In Kenya, women who anticipate male-partner stigma or violence are more than twice as likely to refuse HIV testing ¹¹⁶ . In Uganda, some women’s decision not to initiate PrEP was due to anticipated violence from their partners ^{117, 118} . A study conducted in South Africa found that intimate partner violence and fear this can result in postpartum women not feeling confident enough to request condom use ¹¹⁹ . Female sex workers who have been recent victims of violence find it even more difficult to use condoms with their male intimate partners than with their clients ¹²⁰ .

It has also been reported that men who endorse inequitable gender norms are less likely to take up HIV prevention products like condoms, or services like self-testing ¹²¹ , as they fear it may be perceived as a sign of weakness or vulnerability ¹²² . Prevailing gender norms, which may cause healthcare providers to hold negative attitudes, often discourage at-risk populations from openly discussing sexual health concerns and accessing appropriate care, as seen in studies from Malawi and Mozambique ^{96, 123} . Gender norms that drive inequity contribute to a lack of agency for sex workers in negotiating condom use or asserting their sexual health needs ¹²⁴ . In South Africa, the sex worker organizations SWEAT and Sisonke run a national 24-hour toll-free helpline staffed by trained sex worker counsellors. The helpline addresses concerns including violence and police abuse, offering telephonic and face-to-face counselling. Referrals to paralegals and partner organizations are provided when needed ¹⁰⁶ .

Poverty and unemployment make at-risk populations, particularly women, vulnerable to health challenges due to increased risk-taking behavior. In the face of economic needs, many women resort to transactional sex to sustain their livelihoods, and young girls are often coerced into sexual activities with older men to survive. Studies across South Africa, Kenya, Malawi, and Uganda showed that people with a low socio-economic status (SES) reported significantly lower HIV testing uptake as well as lower usage of condoms than those with a high SES ^{125– 127} . Low economic status has been associated with earlier first sexual experience, lower condom use during most recent sex, having multiple sex partners, increased chances that the first sex act is non-consensual, and a greater likelihood of having had transactional sex or physically forced sex ¹²⁸ . Programs with an economic-support component or cash-transfer schemes have been seen to lower risky sexual activity ¹²⁸ . Conditional cash-transfer programs like the zomba cash experiment in Malawi boosted the acceptability of HIV prevention products among adolescent girls and young women ¹²⁹ . In Tanzania, high-value cash transfers lowered STI prevalence through increased prevention product uptake ¹³⁰ .

Reduced funding, mostly for condoms and VMMC, along with challenges within health systems, including inefficient supply chain design for HIV products in southern and eastern Africa, limits programs’ ability to effectively reach and promote HIV prevention among key populations ^{131, 132} . The efficiency of healthcare delivery systems also structurally impacts the availability and coverage of HIV prevention and treatment products. In Ethiopia, for example, poor supply chain management has led to stock-outs as well as poor data-keeping, and high rates of wastage ¹³³ . Uganda mitigated similar problems through training and on-site mentorship for its logistics management information systems, which reduced stock outages and improved record-keeping ¹³⁴ . Programmatic investments such as EpiC (Meeting Targets and Maintaining Epidemic Control) and BioPIC (Biomedical Prevention Implementation Collaborative) aim to improve program implementation and management, and health information systems through collaboration with local partners.

Education is a key structural determinant for awareness of HIV and demand mobilization. Increased education and higher levels of educational attainment have been shown to be linked to reduced HIV incidence and prevalence. In Botswana, each year of schooling has been associated with an 8.1 percentage-point drop in HIV incidence ¹³⁵ . Similarly, in Zimbabwe, among 15–18-year-old girls, those who are enrolled in school are more than five times less likely to have HIV than those who have dropped out ¹³⁶ . Though enrollment into primary education has been increasing in the region, around 18% of girls in Kenya do not complete primary education ¹³⁷ . Limited access to education for young girls and no avenue for adults in at-risk populations is a barrier that has a significant impact on HIV prevention.

The Ministry of Education in most countries has adopted comprehensive sexuality education (CSE) as a policy measure ¹³⁸ . This is a participatory, curriculum-based approach to equip children and young people with knowledge, skills, attitudes, and values that empower them. The curriculum covers the human body and development, sexual and reproductive health and rights, values, culture, and sexuality, relationships, gender, and diversity ¹³⁹ . In 2023, South Africa published a national HIV literacy framework to improve people’s ability to use health information rather than just understanding it, to focus on “well-informed” decisions than “appropriate” ones, and to drive a public-health perspective among populations ¹⁴⁰ .