The number of new HIV infections has fallen over the years – it declined by 39% from 2010 to 2023. But HIV’s devastating impact on global health persists. In 2023, 1.3 million people acquired HIV – three times more than the 370,000 target set by UNAids. In sub-Saharan Africa, HIV incidence among young women aged 15-24 is decreasing – but they accounted for 27% of all new infections in 2023, and were three times more likely to acquire HIV than male counterparts.
There are a variety of effective, user-centred HIV prevention options. They include oral pre-exposure prophylaxis (PrEp (a daily pill that contains antiretroviral drugs), condoms, vaginal rings (which can be inserted and release drugs), and long-acting injectables.
These are critical in the fight against HIV, but a person needs to decide to use them. It is this user decision process which is fundamental in understanding how to prevent new HIV infections.
My colleagues in public health research and I propose a new, structured way of understanding people’s thought processes when deciding whether to use condoms, medications, or other HIV prevention methods. We call this framework the “decision cascade”. It’s based on behavioural science – the study of how people think, feel and act.
To sustain and accelerate the fight against HIV, we must remember that people are at the heart of the HIV pandemic. People’s choices will be influenced by their personal judgment of whether they truly need and can access the methods and tools available, based on their individual circumstances and priorities.
The decision cascade focuses on the person and the factors that influence their decisions to act. People go through steps when making decisions. The idea behind the cascade is to help them complete each step in order to act.
We hope that the decision cascade will provide researchers, public health interventionists and policy makers with a guide to understanding people’s choices. We also suggest approaches that could work.
Building on previous work, the cascade identifies various types of decision-makers who need HIV prevention products but don’t use them. Unlike many frameworks, it includes those who don’t consider using the services, don’t see a need for them, or face barriers for personal, social, or structural reasons.
The decision cascade focuses on the person and the factors that influence their decisions to act. People go through steps when making decisions. The idea behind the cascade is to help them complete each step in order to act.
The steps are:
Step 1: triggers and cues
Individuals are cued, or triggered, to consider an action, such as using a vaginal ring. Triggers can be external (like getting a flyer about HIV services) or internal (anxiety about having had unprotected sex).
Current interventions often rely on health-focused cues. They focus on rational explanations about health benefits (for example, “using condoms reduces your risk of HIV”). They assume that if people are given logical, clear information about how to protect themselves, they will act accordingly.
The problem is that people may not process information. They may be overwhelmed with other concerns (like financial stress or relationships), or feel that HIV is not a concern for them. They might not focus on HIV prevention, even if the information is available.
Another problem is that people tend to focus on what feels urgent, relevant or important to them at the moment. If someone doesn’t see HIV as an immediate threat or priority, they may ignore prevention messages, regardless of how logical or beneficial those messages seem.
Step 2: reaction
Once cued or triggered, people often react immediately. Their reactions are often subconscious and shaped by what they already associate with HIV. If they have negative feelings or discomfort about the topic, they might ignore the message or react poorly to it.
The brain will make decisions quickly based on biases, like: “I don’t know anyone with HIV, so it’s not a risk for me”, “HIV only affects promiscuous people” or “I’m healthy, so I don’t need prevention”.
These automatic processes can make it harder for people to engage with decisions about prevention efforts, even if it is relevant to them.
Step 3: evaluation of action
Individuals weigh the costs and benefits of acting. This evaluation is complex, subjective, and influenced by biases, personal beliefs, and the trustworthiness of information sources.
For instance, if a person perceives using PrEP as a risk to important relationships, he or she may prefer alternative actions that maintain those relationships.
Step 4: ability assessment
After deciding that action is worthwhile, individuals assess their ability to act on it. This involves practical considerations like knowing how and where to access services or having the necessary resources.
Some barriers include access issues, resource constraints, and a lack of confidence in their ability to use the product.
Step 5: timing of action
Timing is an often-overlooked element in HIV prevention. Even if an individual decides that using prevention services is important and feasible, they must still decide when to act. They might delay if taking action doesn’t seem urgent.
If a person takes all these steps, they will likely act to prevent HIV infection.
The decision cascade framework highlights the need for interventions that support individuals throughout the entire decision-making process. Based on this, we have some recommendations to help design successful interventions:
Trigger engagement: Interventions should use diverse and appealing triggers to capture attention and engage a wide user base.
Address reactions: Focus on positive messaging.
Support evaluations: Provide clear, trustworthy information and highlight the value of acting. Help people weigh the personal costs against the benefits to make informed, realistic decisions.
Enhance ability: Help individuals to take practical steps towards HIV prevention. Examples include extended clinic hours, adolescent friendly services, improved choice of products, digital health approaches, community based services and cash-incentive programmes.
Encourage timely action: Interventions should find ways to reduce delays and support consistent use of prevention services. It could be through making commitments to going for check-ups, for example, or motivating people by linking prevention services with other goals.
Interventions that are designed for the way people actually make decisions are likely to be more effective.
This article is republished from The Conversation, a nonprofit, independent news organization bringing you facts and trustworthy analysis to help you make sense of our complex world. It was written by: Hilton Humphries, Human Sciences Research Council
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Hilton Humphries does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.
