Oral HIV tests: 2 % less accurate, but good enough?
Recent news that a saliva-based HIV diagnostic test is only two percent less accurate than traditional blood tests has intrigued HIV activists and health experts across the world, with many hoping that this will lead to widespread self-testing that can help curb the global HIV/AIDS epidemic.
In the 31 years since it was first recognized by the United States Centers for Disease and Prevention in 1981, the disease has reached epidemic proportions. It claimed about 2.1 million lives in 2007, despite improved access to antiretroviral treatment and care in many parts of the world.
Today, about 34 million adults worldwide live with HIV/AIDS, and the World Health Organization says half of them are women. At least 3.4 million children live with HIV/AIDS and 16.6 million children have been left orphaned by the dreaded disease.
The saliva tests are quick, convenient, non-invasive, private — and now, researchers from Canada’s McGill University Health Centre have found that the tests are also just as accurate, at least among high-risk groups.
Their findings were published Jan. 24 in the journal, The Lancet Infectious Diseases.
How it works
Like a urine test for pregnancy, the HIV oral test is easy to carry out by yourself.
All you have to do is collect the fluid from your mouth. Called oral mucosal transudate, it’s found in your mouth’s blood vessels, and it’s easy to do that: You simply swab the cotton-tipped stick around your entire inner gums and place the stick into the bottom of the vial filled with enzyme solution.
If HIV antibodies are found, a reddish-purple line appears at the top of the stick. But, doctors are quick to point out, this only means that a reaction took place — and does not automatically signify a 100 percent positive result. You have to consult a healthcare provider and take a second test to confirm the result.
The whole process takes about 20 minutes — a fraction of the time it takes for the standard blood tests to show positive or negative results.
Just as effective in high-risk groups
To find out just how effective the oral HIV tests were, a group of researchers led by the Research Institute of the McGill University Health Centre did what is known as a meta-analysis, comparing field research studies from five global databases of the two rapid test methods — blood tests and an oral fluid test, OraQuick HIV.
Researchers found that, in high-risk population — these include intravenous drug users, men who have sex with men and people who engage in unprotected sex—the oral test was just as effective as the blood test in detecting the virus.
More specifically, in high-risk populations, the saliva test is 98.0 percent accurate, while the blood test is 99.68 percent accurate.
For low-risk populations, it was about 97 percent effective.
In news reports that followed the finding’s publication, world public health authorities recognized the potentially big role these self-sampling tests could play in stemming the tide of the spread of HIV/AIDS in high-risk regions like sub-Saharan Africa.
“If you’re really talking about bringing the virus to its knees, the oral test is one more way for people to find out their status,” says Dr. Nitika Pant Pai, a McGill medical scientist and the study’s lead author.
“It has got a lot of potential, increasing access for people to get tested, especially those who feel more comfortable at home,” she says.
So far, the Kenyan government has announced controversial plans for a HIV self-testing initiative that may include approving the widespread use of these oral tests.