The UK’s HIV
epidemic could be partially curtailed by annual testing of high-risk groups and
one-off screening for other populations, investigators report in PLOS ONE. The authors calculated this
strategy would prevent between 4 and 15% of future HIV infections and would be
highly cost-effective. Their estimates assumed current levels of antiretroviral
testing of specific key populations is cost-effective in the UK,” comment the
researchers. “This finding is potentially relevant to other low-prevalence,
According to the
most recent estimates, 98,000 people are living with HIV in the UK. Around a quarter
of these individuals are unaware of their status.
The UK epidemic is
concentrated in three key populations: gay and other men who have sex with men
(MSM); people who inject drugs; and black African people.
recommend annual HIV tests for gay men and other individuals who may be at higher risk.
Universal screening is also recommended in settings where local HIV prevalence
in the US and France suggests that certain “test and treat” strategies can
cost-effectively prevent a substantial number of new HIV infections.
A team of UK and
US investigators therefore developed a model to estimate how many new HIV
infections would be prevented by specific screening strategies and also how
affordable these strategies would be.
They estimated the
impact of testing strategies on HIV incidence and quality-adjusted life years
(QALYS) – an important measure of cost-effectiveness. HIV testing and
counselling was assumed to cost £44 per person, but the extra costs of
achieving universal HIV testing coverage were not incorporated.
If current HIV
testing and treatment levels remained unchanged, then HIV incidence would
remain more or less steady with approximately 3500 new infections each year.
More than 6100 people would be newly diagnosed with HIV in 2013, and 5400 of
these would involve people from high-risk groups.
If it were possible
to provide HIV testing to all adults (aged 15 to 64) every three years, 1% of
all future infections would be prevented, while universal testing every year
would prevent 5% of future infections. These reductions in incidence would be a consequence of the impact of
antiretroviral treatment on infectiousness. If diagnosis with HIV were
accompanied by a 50% reduction in number of sexual partners, then between 3 to 18%
of future infections would be averted. Annual universal testing would diagnose
16,000 infections in the first year, substantially reducing the number of
individuals living with undiagnosed HIV infection.
cost-effectiveness was a major limitation of this strategy.
In the modest
optimistic scenario (50% reduction in the number of sexual partners), annual
HIV testing for all adults would cost £64,000 per QALY gained. With no
behaviour change, the cost was over £100,000 per QALY gained. It would take
approximately 11,000 tests to identify one person with HIV.
programme targeted at high-risk groups that was combined with one-off screening
for other adults prevented nearly as many infections as universal screening,
but at a much lower cost.
In this scenario,
100% of MSM, people who inject drugs and black African people would test every
year and other people would take an HIV test once.
would prevent between 4 and 15% of future infections. There would be 15,000 new HIV
diagnoses in the first year – almost as many as would be achieved with
with one-off screening for other adults was projected to cost £17,500 per QALY
gained. A total of 2500 tests would be required to identify an individual with
undiagnosed HIV infection.
uptake of antiretroviral therapy with targeted testing and one-off screening
for other adults was shown to prevent up to 23% of future infections at a cost
of £26,800 per QALY gained. This strategy would remain cost-effective with 100%
uptake of HIV therapy.
therefore conclude a targeted testing approach with one-off testing for others,
would provide 80% of the benefits of universal HIV testing but at only 14% of
the cost over ten years. “At £17,500/QALY gained, this strategy is well below
established UK cost-effectiveness thresholds of £20,000-£30,000/QALY gained.”