Natsal: Protecting public health by understanding sexual behaviour
Over nearly four decades, the National Surveys of Sexual Attitudes and Lifestyles (Natsal) has provided evidence about sexual behaviour and attitudes across Britain. Here we explore how Natsal influences public health decisions and can help us navigate emerging sex and wellbeing issues.
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Across Britain, new generations are growing up protected from human papillomavirus (HPV) – and the cancers it causes. For women born since September 1995, the HPV vaccination programme has almost eliminated the risk of cervical cancer. But how did experts anticipate its impact and justify a national rollout? That’s where Natsal comes in.
Improving sexual health and wellbeing starts with understanding sexual attitudes and lifestyles. Natsal – a representative survey of the British population conducted roughly once a decade – has been carefully accumulating evidence on this topic for more than 35 years. In this time it has drawn on data from more than 45,000 people.
Natsal’s insights helped make the case for the original HPV vaccination programme in 2008. “The mathematical models were all based on Natsal behavioural data, on sexual mixing data,” recalls UK Health Security Agency epidemiologist, Kate Soldan, allowing decision makers to “see what impact different designs of a vaccination programme could have on the prevalence of infection.”
Not only that, but Natsal’s sample bank enabled experts to estimate how common HPV was before the vaccination programme began – filling in gaps in NHS datasets. Kate notes that this baseline “has been very important for understanding the impact of the programme.”
HPV is just one of the many health challenges Natsal has helped tackle. “We’ve surveyed many thousands of people, and we’ve used that…to inform all sorts of practice and policy,” explains Anne Johnson – co-creator of the first Natsal study. “Our work has informed the development of the Chlamydia Screening Programme… [and] policy on sex education [and] contraception services.”
Natsal's long-term, population-level view of behaviour is essential for understanding how health risks emerge and change over time. It's an evolving platform for discovery, offering a unique and incredibly rich resource for researchers and policymakers.
Helena Wells
Research Manager
Wellcome
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Where it started – a search for reliable data in the early days of HIV
The survey was originally initiated in response to the emerging HIV epidemic in the 1980s. It aimed to improve understanding of how HIV might spread in Britain, and what might help prevent that spread. While other scientists focused on the biology of the disease, Anne and the Natsal team zoomed out – looking at the problem through a social and behavioural lens.
Back then, social taboo around the subject of sex meant reliable data was lacking and misinformation was rife, obscuring understanding and effective routes to prevention. “There was immense prejudice and fear about [HIV],” observed Anne.
Against this backdrop, the Natsal team set out to carefully develop questionnaires that would put participants at ease, including confidential self-completion sections for sensitive topics. As Wendy Macdowall, who’s been part of the Natsal team since the second study, explains “people are sharing deeply personal information. Designing the survey is about care as much as science. That means not overburdening participants, giving them control, and recognising that some questions can be sensitive or triggering.”
Watch: The rocky road to launching Natsal
Explore Natsal’s fascinating origin story and impact through the eyes of Anne Johnson, co-creator of the first Natsal study.
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Anne Johnson, co-creator of the National Survey of Sexual Attitudes and Lifestyles (Natsal), explains how a groundbreaking study launched during the HIV epidemic went on to shape policies on HIV prevention, HPV vaccination, sex education and sexual health services across the UK.
Thatcher's ban – why Wellcome stepped in
Still, asking a population about their sexual practices was not straightforward at first. Many considered the subject “private”, including Margaret Thatcher, who was concerned that “people…would be deeply offended by questions of this kind."
Indeed, despite careful pilot work showing that people were willing to participate, the study was deemed too intrusive at the eleventh hour. “We were all ready to go, but…unfortunately we couldn’t get agreement from government agencies to fund the survey,” explains Anne.
Wellcome was approached and, after rapid independent review, recognised Natsal’s scientific importance, rigour, and relevance to public health. “Within ten days of [Thatcher’s] ban, Wellcome…agreed to fund the survey,” says Anne. The work went ahead, creating a trusted evidence base that was instrumental in informing HIV prevention, control, and service provision.
Its impact only grew from there.
We quote Natsal in everything we do and have made it accessible for approximately 100 partner organisations and hundreds of schools.
Wellcome has continued to support subsequent waves of Natsal, alongside other UK funding partners including the Medical Research Council (MRC), the Economic and Social Research Council (ESRC), and the National Institute for Health and Care Research (NIHR).
The next chapter – protecting health and wellbeing and the digital world
Data from Natsal remains crucial to public health interventions. "It can now inform the national NHS cervical cancer screening programme," says Kate Soldan. "Because that programme now needs to focus its efforts on engaging and doing the right testing of women who have not been protected by vaccination."
And as sexual lifestyles evolve, Natsal remains a trusted source of data for decision-makers, policy-makers, and those campaigning for change. “Each wave of Natsal responds to what society is dealing with at that moment – from HIV and sexually transmitted infections (STIs) to wellbeing and sexual violence,” explains Pam Sonnenberg, principal investigator on Natsal-4 – the latest study, set for publication later in 2026.
Future studies will help us understand the emerging issues impacting health and wellbeing – from sexual identity to our increasingly digital lives.
The latter will be a key area for ongoing study, according to Natsal’s Wendy Macdowall, who is leading on the topic of digital technologies: “[Natsal-3] did not ask about things like AI companions, sex robots, digital intimacy, and how far any of this is going to go. Digital intimacy is changing, and it’s something we need to understand better.”
Natsal, she says, is uniquely positioned to deliver this insight: “Without a study like Natsal, we’re left relying on assumptions, anecdotes, or extreme narratives. The data helps distinguish what’s common, what’s changing, and what actually needs attention.”
As Anne puts it, Natsal reveals “what is going on, not what we think is going on.”
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