At a 2017 workshop in Chennai to understand people’s hope for a human immunodeficiency virus (HIV) vaccine, a participant said such a vaccine may make society more “morally corrupt”. He believed that a preventive vaccine may encourage more people to engage in unsafe sex with multiple partners. The respondent had HIV and had experienced stigma and discrimination.
This is called survivor’s bias, a common behavioural reaction, but there is a lesson in his response for HIV vaccine developers — the acceptability of an HIV vaccine will not be an easy journey.
The first human trials of a series of mRNA-based vaccines against HIV began in early 2022 in the US. As epidemiologists and virologists express ‘cautious optimism’ about their success, it is important to engage behavioural scientists from these early stages of development about a possible rollout.
Vaccine hesitancy is a growing concern that WHO has ranked as top ten threats to global health. Given that hesitancy stems from distrust, the issue must be tackled right from the stage when the product is being designed.
Experience shows it is prudent to involve end-users and communities in vaccine development. Social, cultural and religious beliefs can support or undo the benefit of biomedical innovations. In the past, we saw this with vaccinations for smallpox and polio, and more recently with human papillomavirus (HPV) and COVID-19. Individual and community beliefs, lack of trust, quality of support, stigma, and other factors impacted the acceptance and uptake of these vaccines. Even PrEP, a daily pill that can prevent HIV, meets resistance due to the stigma associated with the disease and the fear of being labelled as prone to a higher risk of HIV.
For an HIV vaccine to be acceptable, experts need to strategise from users’ behaviour-resistance point of view.
Gagandeep Kang, a professor at the Wellcome Trust Research Laboratory in Christian Medical College Vellore, says bodily integrity matters the most to people while making health-related choices. “In a way, vaccines breach that integrity. An HIV vaccine, whenever it comes in the future, will struggle with this,” she says adding scientists must critically think about how to place biological solutions within prevailing social norms.
In his book Change: How to Make Big Things Happen, Damon Centola suggests that, while information and disease spread through ‘simple contagions’, behaviour change often takes place in ‘complex contagions’ meaning it requires multiple sources of reinforcement. If an idea needs to overcome more resistance, it is likely that its acceptance will be like a complex contagion.
Based on Centola’s work, the journey of an HIV vaccine needs to be understood through this prism of complex contagions where an intervention needs to cross some critical barriers:
• Credibility barrier: People may be sceptical about the effectiveness and safety of a vaccine. Therefore, repeated confirmations from a trusted network would matter in such a case. As more people adopt the product, more social proof is garnered. An example is the case of the polio vaccine — the scientific response had to leverage behavioural science knowledge to address growing scepticism. Health authorities partnered with local communities to find credible sources like religious leaders to relay information and nudge communities to get vaccinated.
• Legitimacy barrier: Vaccines must be introduced alongside efforts to reduce situations that fuel fear of embarrassment or social sanctions. Adoption of an HIV vaccine will need social approval to overcome barriers related to stigma and/or embarrassment. The more people in the network get vaccinated, the lesser the perceived social risk.
Mona Balani, a project director at the National Coalition of People living with HIV in India, says uptake for an HIV vaccine might be low due to poor risk perception among people who may be at risk. “Additionally, they might fear social embarrassment or being othered as wanting to take a vaccine would mean acknowledging that they are indulging in unsafe practices,” she points out.
• Coordination barrier: For the intervention to be successful, more people must adopt it simultaneously. Focusing on just strengthening supply and access will not resolve this challenge as social norms may be a hurdle. It is easier to accept and adopt a product, when more people get vaccinated together. The success of the COVID-19 vaccine was partially because of the huge number of people who got the shots at the same time, or within a short period.
However, the pandemic also highlighted the challenge of equitable access and uptake of vaccines. Mitchell Warren, Executive Director of the non-profit AIDS Vaccine Advocacy Coalition (AVAC), points out that COVID-19 vaccine development showed while it is possible to compress timelines and urgently develop new technologies, equitably reaching these technologies to people with the greatest need remains a challenge. “We have to ensure that community engagement, behavioural science and person-centred research is integrated into the development process so that uptake of new technologies is more rapid.”
• Excitement: Social acceptance from peers is critical to boosting enthusiasm for new products and practices. During the rollout of COVID-19 vaccines, people eagerly waited to get vaccinated, making for social reinforcement. Agencies responsible for immunisations must make the best use of this emotional excitement in their call to action.
Balani says while the scientific community has been talking about an HIV vaccine for years, the latest scientific developments around this are seldom shared with the masses. “There is a clear gap in information flow which can lead to distrust among community members.” People living with HIV must be engaged from the beginning of the vaccine development process for them to trust it, and eventually become advocates of the vaccines.
• Digital realities: The blurred line between digital networks and physical contagions has given rise to newer risk behaviours. Information and misinformation now spread at lightning speed, and the reach of a hashtag is not something to be undervalued.
An accessible, affordable life-saving solution can falter on these barriers if people’s resistance to change is not accounted for. This is where behavioural science plays an important and complementary role in vaccine science. It can help design strategies calibrated to users’ needs and for specific communities where resistance is higher.
“Science is dynamic. With any vaccine, you cannot await complete quantification of risk before it is made accessible to the public,” Kang says. In the absence of such risk assessment, it is human to fear the side effects. “Tools from behavioral science can play a complementary role in pre-emptively understanding some of the gaps and pro-actively bridging these gaps,” she adds.
Warren says hundreds of millions are invested in large trials but nothing comparable on disseminating the results of the science to achieve public health impact. “This is not unique to any disease, we have seen it in the lack of global vaccine equity in the COVID-19 response and we’ve seen it in TB and HIV.”
Inviting investment in behavioural science can be frustrating as funders are tired of huge investments in this research area. Human behaviour is dynamic and past evidence may not be relevant in current situations. Similarly, while evidence collected for one population subset can inform research for the same/different population subset, it cannot substitute the need for further and more context-specific research.
Without such investments, the gap between vaccine awareness and its adoption cannot be addressed. While scientists adopt a disease-centred approach, understanding user needs through behaviour sciences during product design is critical. Scientists need to stop viewing behaviour science as a soft issue and instead work alongside behavioural experts to galvanize support for biomedical solutions via social reinforcement.