* High risk groups not getting enough HIV health services
* Gay men, sex workers, drug users, prisoners are key
* WHO says gay men should take AIDS drugs as prevention
By Stephanie Nebehay and Kate Kelland
GENEVA/LONDON, July 11 - Five key groups, including gay men, prostitutes and prisoners, have stubbornly high rates of HIV that are threatening progress in the global AIDS battle, the World Health Organisation (WHO) said on Friday.
These people are most at risk of becoming infected with the human immunodeficiency virus that causes AIDS, yet are least likely to get HIV prevention, testing and treatment services, the Geneva-based United Nations health agency said.
"Globally we are failing certain populations that have the greatest risk yet we know have universally poorer access to health services. These are men who have sex with men, sex workers, transgender persons, specifically transgender women, persons who inject drugs and persons who are in prisons or other closed settings," Gottfried Hirnschall, director of the WHO's department, told reporters at a briefing.
"We are seeing exploding epidemics in some of these key populations," he said, adding that these groups account for up to 50 percent of new cases of HIV infection.
The WHO said studies estimate that female sex workers are 14 times more likely to have HIV than other women, gay men are 19 times more likely to have HIV than the general population, and transgender women are almost 50 times more likely than other adults to have HIV. For injecting drug users, the risks of HIV infection can be 50 times higher than the general population.
For the first time, the WHO said it "strongly recommends" that men who have sex with men should consider taking antiretroviral AIDS drugs as an extra way of protecting themselves against HIV infection, alongside using condoms.
Such an approach, known as pre-exposure prophylaxis or PrEP, is a way for people who do not have HIV but are at risk of getting it to protect themselves by taking a single pill, usually a combination of two antiretrovirals, every day.
PrEP, when taken consistently, has been shown to cut the risk of HIV infection in high risk people by up to 92 percent.
"The reason that we are adding this to our prevention choices for men who have sex with men is that we have these very worrying increases in HIV incidence," said Rachel Baggaley, coordinator of the WHO's department for HIV/AIDS.
AIDS experts estimate that globally, HIV incidence among gay men could cut by 20 to 25 percent through PrEP, averting up to 1 million new infections in this group over 10 years.
Some 35.3 million people worldwide are infected with HIV, but the rising number of patients reflects great strides in recent years in developing sophisticated HIV tests and combination AIDS drugs and getting them to many of those who need them to stay alive.
As a result, the annual AIDS death toll is falling, dropping to 1.6 million people in 2012 from a peak of 2.3 million in 2005. New HIV infections are also steadily declining, by one-third in 2013 from 2011.
This progress has raised hopes for a world free of AIDS or HIV in our lifetime.
Yet figures show the key high risk populations continue to have high infection rates, and appear to be hard to reach in terms of getting the right prevention messages, or getting them the testing and treatment health services they need.
Hirnschall said that in many countries, gay men, sex workers and other marginalised groups are left out of national HIV plans and excluded by discriminatory laws and policies.
"None of these people live in isolation," he warned. "Sex workers and their clients have husbands, wives and partners. Some inject drugs. Many have children. Failure to provide services to the people who are at greatest risk of HIV jeopardises further progress against the global epidemic."
The WHO report, released ahead of the International AIDS Conference in Melbourne, Australia, which begins on 20 July, said that by the end of 2013, around 13 million people worldwide were taking AIDS drug treatment. This has led to a 20 percent drop in HIV-related deaths between 2009 and 2012, it said. (Writing by Kate Kelland; Editing by Richard Chang)