An estimated 29,000 individuals in France were living with undiagnosed
HIV infection in 2010, investigators report in the online edition of AIDS. Sixty per cent of people with undiagnosed
HIV had a CD4 count below 500 cells/mm3 and were therefore
eligible for immediate antiretroviral therapy. The investigators believe their
findings are of relevance to HIV screening strategies, and that universal HIV
testing for men would be appropriate and cost effective, especially in high-prevalence
cities, such as Paris.
People living with undiagnosed HIV are unable to benefit from HIV treatment and care.
Research has shown that the majority of new HIV transmissions originate in
undiagnosed individuals, and late diagnosis increases the risk of serious HIV-related
illness and death.
HIV testing strategies in France have traditionally relied on voluntary counselling and
testing. Annual HIV tests are recommended for high-risk groups such as gay men, people who
inject drugs and heterosexual people from high-prevalence settings who report
multiple sexual partners. In addition, all individuals aged between 15 and 70
are recommended to have at least one HIV test during their lifetime.
To better inform HIV screening strategies, investigators used mathematical modelling techniques to estimate new infections, time to diagnosis and the number of people with undiagnosed HIV at the end of 2010.
Approximately 83,000 people newly acquired HIV in France
between 2000 and 2010. Of these, an estimated 29,000 remained undiagnosed at the end of
2010. The majority (70%) of those undiagnosed individuals were men. As regards HIV
risk group, gay and other men who have sex with men (MSM) comprised 32% of
undiagnosed individuals, French-born heterosexuals 35%, non-French-born
heterosexuals 32% and people who inject drugs 2%.
Undiagnosed prevalence was 10 per 10,000 among men compared to 4 per
10,000 among women. The prevalence in men was at the 0.10% threshold at which
universal HIV testing becomes cost effective.
Analysis by exposure groups showed that the rate of undiagnosed
infections was highest among MSM at 295 per 10,000, followed by people who inject drugs (62 per 10,000), non-French-born heterosexuals (36 per 10,000) and was
lowest among French-born heterosexuals (3 per 10,000).
The authors estimated that 29% of undiagnosed individuals had acquired HIV within the last year and that 16% acquired HIV five
or more years ago. There was a higher prevalence of old infections among men
than women (18 vs 12%). Heterosexual men were the group most likely to have
been living with an undiagnosed infection for five or more years (20%).
French national guidelines now recommend the initiation of HIV therapy
at a CD4 count of 500 cells/mm3 and 60% of undiagnosed individuals
had a CD4 count below this threshold. The investigators were especially
concerned that approximately a fifth of people with undiagnosed HIV had a CD4 count
below 200 cells/mm3. They
note that “a recent study showed that, in France, patients presenting to care
with CD4+ below 200 cells/mm3 were 13 times more likely
to die from HIV within the next 6 months after enrolment than patients
presenting with CD4+ above 200 cells/mm3.”
Heterosexual men were the group most likely to have a low CD4 count.
“New screening strategies to reach out to undiagnosed individuals are
needed in order to reduce HIV transmissions and ensure timely access to HIV
care for these individuals,” the authors conclude. “Universal screening of men
could be cost-effective in the areas most affected by the epidemic, such as the
metropolitan area of Paris, and thus should be further evaluated.”