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Trust introduces a digital solution to prevent transmission of sexual diseases amongst gay men, leading to less than 1 per cent HIV seroconversion rate


    • Number of gay men testing HIV positive in London rose every year between 2008 and 2015
    • Low levels of self-esteem and absence of emotional/educational support led to risky sexual practices such as chemsex
    • Lack of awareness/knowledge regarding other prevention measures prevailed
    • Lifetime costs of treating HIV amounted to £360,000
    • Provide immediate diagnosis/treatment for gay men at risk of getting HIV


    • Launched PRIME – a digital solution to reduce the risks of HIV transmission in gay men
    • Encouraged the adoption of personalised risk reduction strategies
    • Optimised mobile phones as the target group had high engagement with mobile media for sexual purposes
    • Promoted Pre-exposure prophylaxis (PrEP) and other generic medication
    • Conducted Total Bareback - monthly testing for events when no precautions were taken


    • Public Health England reported a 29% drop in London’s gay men between 2015-16
    • Assisted with physical health/mental wellbeing of users, reducing self-esteem issues
    • Over 6500 men joined PRIME, decreasing diagnoses of other sexually transmitted infections
    • 67% users chose PrEP and 85% agreed the project helped them stay HIV negative
    • Less than 1% caught HIV per year, saving NHS £16.9 million


The number of gay men testing HIV positive in London rose every year between 2008 and 2015. 56 Dean Street is a sexual health service in central London. It reaches more high risk gay men than any other UK clinic. In 2015 it diagnosed half of the London’s HIV in gay men, giving it a unique opportunity to reduce HIV transmission.

Dean Street PRIME is an innovative, digital HIV risk reduction and lifestyle intervention targeted at gay men at extremely high risk of HIV. (Over 10% risk per year). PRIME aimed to recruit 3000 men and to halve their risk to 5% per year. PRIME was optimised for mobile as the target group had high engagement with mobile media for sexual purposes. It encourages the adoption of one of 5 personalised risk reduction strategies.

A monthly text contains a link to updated content on a ‘Google hidden’ website. ( PRIME launched in early 2016. Over 6500 men have joined PRIME. Public Health England (PHE) found the HIV seroconversion rate is less than 1% in PRIME users. Between 2015-7 HIV diagnoses at the clinic dropped by 81%. PHE reported a 29% drop in London’s gay men between 2015-16 (2017 figures pending).


There have been significant advances in understanding how we can prevent HIV transmission. Condoms are no longer the only option. HIV positive people on effective treatment are not infectious. We also know that people are most infectious in the first few months after catching HIV. This makes immediate diagnosis and treatment very important. Preventive PrEP drugs taken before sex are very effective. (Pre-Exposure Prophylaxis).

In addition P-E-P, an emergency treatment take after exposure, is another option if condoms fail (Post Exposure Prophylaxis). Despite this, the number of gay men testing HIV positive rose every year 2008-2015. Gay men often had limited understanding of these new options. We identified ways to predict a gay man was at high risk in the next year. Modelling suggested that we saw about a third of all the gay men likely to seroconvert in London.

Preventing infection would not only protect them, but also their partners. The lifetime costs of treating someone with HIV are £360,000. We aimed to half the men’s risk as this was likely to be highly cost effective. We chose a digital solution to be convenient for patients, and practical and cost effective way to reach large numbers with limited resources.


People were offered PRIME if any of the following applied. There was evidence that all were linked to a 10% chance of catching HIV in the following 12 months.

• Rectal gonorrhoea/chlamydia.

• Early syphilis.

• Requiring Post Exposure Prophylaxis.

• Condomless receptive anal sex with multiple partners.

We aimed to recruit 3000 men and reduce their risk to 5% Over 6500 people have joined PRIME. Less than 1% became HIV positive per year. In March 2018, 546 PRIME members responded to a survey monkey designed to help develop future content. 85% agreed with the statement ‘I feel PRIME has helped me stay HIV negative’

Testimonials “I’m not exaggerating when I say that PRIME has literally changed my life. If you could see my medical records before and after PRIME. It’s astonishing.” ‘PRIME has permitted me to stay on top of my sexual health in ways that were not available to me before now. It not only assists with my physical health, but also tremendously with my mental wellbeing’ ‘PRIME has helped reduce my self esteem issues somewhat, which has helped me look after my health better. I still struggle, but PRIME is helping me.’


The costs of PRIME were supported by the ‘MAC AIDS Foundation’ and ‘Chelsea and Westminster Charity’. Funds are limited and so the project links users to existing organizations and resources. Public Health England are collaborating with the clinic to evaluate outcomes of PRIME users using ‘GUMCAD’ data. They are interested in using it a model of HIV prevention outside London. It links to and promotes NHS home testing services.

PRIME was used to develop the ‘Plan ZERO’ tool. It was promoted at Pride, on Facebook and Twitter and through broadcast commercials on Grindr ‘dating’ app. A paper version was distributed in London gay venues. Dean Street PRIME works also closely with the ‘Wellbeing’ programme which runs community events in local MSM venues. The project links with MSM bars, clubs and promoters. (e.g. The ‘World AIDS Day HIV testing event’ in G-A-Y Bar and ‘Let’s Talk about Gay Sex and Drugs’ in Ku Bar).

It promotes gay community groups offering an alternative to sexualised bars/clubs. As PrEP is not routinely available on the NHS, PRIME also links with community organisations such as ‘Prepster’ and ‘I Want PrEP Now’. It promotes the PrEP IMPACT trial and other sources of generic drugs.


Public Health England have helped evaluate PRIME. Their data suggests that diagnoses of other sexually transmitted infections also fell in PRIME members. High risk gay men HIV tested more frequently. In those testing HIV positive, the time to starting treatment improved. People were offered PRIME because, statistically, their chance of catching HIV was at least 10% per year of follow up.

Once on PRIME most users adopted an effective prevention strategy. (67% chose Pre Exposure Prophylaxis). Follow up data shows that after joining, less than 1% of PRIME members caught HIV per year of follow up. The PRIME digital solution allows the service to support to over 6500 people that could otherwise never be achieved with the staffing resources available. Community events, workshops and Facebook Live allow people to interact with staff in real time.

Staff can also give detailed information using video content that is then available on YouTube. It costs the NHS £360,000 to provide lifetime care for every HIV positive person. In the first 6 months alone there were 47 less cases of HIV diagnosed than expected. This equates to a £16.9 million cost saving to the NHS


Focus groups of gay men helped design the intervention to ensure it had a culturally appropriate tone and content. Key findings were the target group often

• Exhibited low levels of self-esteem that led to risky sexual practices such as ‘chemsex’.

• Wanted to ultimately settle down with one partner.

• Was looking for emotional and educational support.

• Perceived existing HIV prevention messaging to be prejudiced towards their behaviour, didn’t speak their language and assumed all MSM had the same lifestyles.

• Placed high value on easy access to testing services. Focus groups ensured that the names of the 5 strategy options were not perceived as judgemental.

• Take a Break (A period of abstinence)

• Just Us – (Monogamous relationship with testing and relationship agreement)

• Condoms Plus ( Condoms with P-E-P if things go wrong).

• Pre exposure prophylaxis

• Total Bareback (Monthly testing if no precautions) Follow up groups and online surveys have helped refine content, workshops and community events.

• 75% of PRIME members wanted more video content containing experts giving advice & information.

• Greater focus on Pre Exposure Prophylaxis as 67% were using it

• Development of interactive tool to help choose risk reduction options

• Development of interactive tool to self-assess whether P-E-P is recommended


Key individuals

Dr Alan McOwan