Gay and bisexual men in British Columbia will soon have greater access to a more accurate form of HIV testing that can detect the virus as soon as a week after exposure.
A BC Centre for Disease Control (BCCDC) study released Oct 9 found that pooled nucleic acid amplification testing (NAAT), also known as the early HIV test, greatly improves the diagnosis of early or acute HIV infection.
The pilot project, which will now be an ongoing program, examined HIV test results from men over the age of 18 at six clinics in Vancouver used by gay and bisexual men from April 2009 until March 2012. The research found that 25 men who would have received a negative result under standard HIV testing were diagnosed with acute HIV by pooled NAAT.
The study, titled “Targeting Screening and Social Marketing to Increase Detection of Acute HIV Infection in Men Who Have Sex with Men in Vancouver, British Columbia,” was released in the Oct 9 edition of AIDS, a peer-reviewed scientific journal that is the official journal of the International AIDS Society. The researchers estimate that the new protocol may have prevented 25 to 75 new infections.
“This will increase the ability to diagnose early acute HIV infection, and this has the potential to effect the course of the epidemic,” says study co-author Mark Gilbert, a physician epidemiologist in sexually transmitted infections at the BCCDC.
“The basic premise is that we know that acute HIV infection is in the first few months after infection. Viral load is very high, and that’s one of the factors that influences how infectious someone is. A high viral load increases the chance of passing on HIV.”
Pooled NAAT is a form of testing developed in the United States that detects the presence of HIV in the blood before antibodies are detectable. Pooled NAAT tests can detect the virus seven to 15 days after an infection, compared to 20 to 30 days using standard tests.
“There have been some studies that suggest that up to half of infections are from someone with acute infection,” Gilbert says. “Most people in the acute phase of infection are unaware that they have HIV and are not taking measures to prevent HIV, and most people who get diagnosed take measures to prevent transmission. The sooner you know you have HIV, the sooner you take measures to prevent passing on HIV to other people. Giving people diagnoses at a very early stage really maximizes the prevention of HIV.”
Wayne Robert, executive director of the Health Initiative for Men (HIM), says pooled NAAT tests are an effective and cost-effective tool in HIV prevention.
“The earlier you identify, the earlier guys can respond to their situation,” he says. “In the case of acute HIV, they can take measures to prevent onward transmission and can make the decision of taking antiretroviral drugs earlier in the process of the disease, for example.”
The study also found that social marketing campaigns done in conjunction with pooled NAAT were effective in increasing the rate of acute HIV diagnosis, as well as the frequency of testing.
To that end, the BCCDC, in conjunction with HIM, implemented two campaigns. The What Are You Waiting For campaign ran from December 2009 to February 2010 and sought to raise awareness of new testing technology, including NAAT and rapid testing. The Hottest At the Start campaign, which ran from June to August 2011, focused on the increased transmission risk associated with acute HIV.
“These campaigns were targeted to gay men, and gay men really responded to it,” Robert says.
“When we started the campaign, a lot of guys had no concept of acute HIV, and they thought the longer you had it the more infectious you are, when you are, in fact, more likely to transmit in the acute phase. We know that guys incorporate this information and respond to it.
“There are a lot of guys keeping an eye on these developments,” he says, “just like we were earlier adopters of social media and online interactions and so on, also they can incorporate that into their health strategies.”
Gilbert says they are exploring other sites in BC where the program could be introduced.
“We are looking at sites where there is a history of people being diagnosed with HIV,” he says. “We’re talking to people in different regions of the province to get a sense of good clinics to implement it at.”
Research for the study was funded through the Canadian Institutes of Health Research and supported through the Seek and Treat for Optimal Prevention of HIV/AIDS (STOP HIV/AIDS) program.
“Our government is committed to reducing the spread of HIV by ensuring those living with HIV/AIDS have access to the best care and treatment, and it is very exciting that this groundbreaking research is going on right here in BC,” says a press release from BC’s minister of health, Terry Lake. “As part of our vision of an AIDS-free generation, we’ve committed $19.9 million in annual funding to health authorities to support the expansion of STOP HIV/AIDS throughout BC, and we are the only province in Canada showing a consistent decline in new HIV diagnoses.”
New infection rates among gay men, however, rose from 152 new cases in 2010 to 167 in 2011.