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Entries in Public health issue (2)


Time for a new gold standard in HIV viral load monitoring

This past year has brought more good news in the battle against HIV/AIDS with UNAIDS stating, “On the cusp of the fourth decade of the AIDS epidemic, the world has turned the corner—it has halted and begun to reverse the spread of HIV.” UNAID’s 2012 report cited 700,000 fewer new HIV infections in 2011 than in 2001. AIDS-related deaths have been reduced by one-third in the past six years. And access to antiretroviral therapy (ART) continues to grow at unprecedented rates. But as the battle against HIV enters a new phase, it introduces new challenges to the healthcare community, particularly with regard to diagnostics. In response, the World Health Organization and UNITAID have dubbed the next ten years, “the decade of diagnostics.” In their session at AIDS 2012 in Washington D.C. they emphasized the important role that cheaper, simplified diagnostics must play in the next phase of the campaign to stem the HIV pandemic. This emphasis is redefining the role of HIV viral load testing in treatment and is placing new demands on how these tests are conducted. 

Number of people newly infected with HIV, Global, 1990-2011

UNAIDS Report (2012)

For decades the gold standard for HIV viral load diagnostics have been RNA-based tests. But in this new diagnostic landscape I see centralized RNA-based testing rapidly losing relevance to tools that are better suited to meet the diagnostics challenges that we see today in both the developed and developing world. Most notable among these are: a) the need to scale HIV viral load monitoring in step with the burgeoning number of men, women and children entering treatment, b) managing the rise in drug-resistant HIV strains that accompany greater access to ARV treatment and c) address the diagnostic needs of infants born to HIV-positive mothers. 

In low-to-middle income countries, access to HIV viral load testing has become a more critical issue given the recent increase in access to ART.  According to the World Health Organization (WHO), there was a 20-fold increase in the number of people receiving ART in developing countries between 2003 and 2011, and a 20% increase in just one year (from 6.6 million in 2010 to more than 8 million in 2011). The rapid increase in access to Antiretroviral drugs (ARV) has triggered a corresponding increase in the need to monitor those receiving treatment. This helps to ensure the virus is being suppressed and helps the doctor know when the patient needs to be switched to a new treatment regimen.  

Originally developed for use in North America and Europe, RNA-based tests are proving impractical for decentralized use in low-to-middle income countries. Around 70% of the world’s HIV population live in sub-Saharan Africa. As a result, district hospitals and clinics outside the capital have to either send blood samples away to a central reference hospital or, more likely, forgo HIV viral load monitoring altogether. In light of this, it seems the gold standard is shifting in favor of a HIV viral load monitoring solution that can deliver the same reliability in a decentralized model with testing conducted near-patient.

This has created a flurry of innovation in the HIV viral load POC testing arena. Maurine Murtagh has identified 13 different entrants in this area in the 2nd edition of UNITAID Diagnostic Technology Landscape Report.  Of the options available today, Reverse Transcriptase (RT)-based testing seems to offer the most plausible solution on several fronts. First, RT is a very stable marker since it is not affected by mutation and is always present when the HIV virus is replicating. Since RT-based tests do not target a specific nucleic acid sequence, they are able to quantify all types and subtypes of HIV, including new strains, without any modification to the test. RT-based tests have historically been significantly less expensive than RNA tests both in terms of start-up and running costs. Further, the RT platform has an unmatched track record among this next generation of HIV viral load tests. It has been in the field for over a decade with more than 40 peer-reviewed journal articles and over 350,000 tests run. Several studies over the past decade have compared ExaVir™ Load to the gold standard PCR tests and all have found excellent correlation with RNA-based tests. 

The benefits of RT-based HIV viral load testing go beyond resource-limited settings. In the developed world, HIV viral load monitoring is a main line of defense against the rise in drug resistant strains of HIV.  Eric Rubin, professor of immunology and infectious diseases at HSPH put it eloquently, "Drug resistance is the product of success: With treatment, we have drug resistance." Since ARV treatment has been more prevalent in developed countries, resistance has mainly been a problem for these nations.  For instance, a recent study in San Francisco revealed that 60 percent of new HIV infections are drug resistant. One of the key factors in stemming this tide is early detection of treatment failure through HIV viral load monitoring of all HIV positive patients. Since healthcare systems the world over are straining to manage budgets, a more cost-effective decentralized HIV viral load monitoring solution may benefit developed nations as much as it does low-to-middle income countries.  

In areas where the subtype of the individual may be unknown RT-based testing provides additional advantages. This has not been much of a concern in the US where the vast majority of HIV-1 infections are subtype B—98 percent according to some surveys. But an article from CAP Foundation asserts that it may be time for the US to  “catch up to what’s happening in Tanzania and elsewhere in Africa. Specifically, HIV-1 subtypes common in Africa may be making inroads in the United States, as they have in Europe.”  Of the testing options available, only RT-based testing is able to detect any HIV activity without modifying the test — including new HIV strains.

World map of Global distribution of HIV-1 strains

IAVI Report (2003)

Lastly, with half of the world’s HIV population being women and many of them of child-bearing age, there has been increased focus in recent years on mother-to-child transmission. Here too we see great strides have been made with 57% of HIV positive pregnant woman living in low-and middle-income countries receiving treatment in 2011. One persistent problem has been the early infant diagnosis (EID) since standard rapid tests won’t work on newborns. This is another area where RT-based testing has been found to convey an advantage. Over the past year more studies have confirmed that in addition to RT-based EID solutions being significantly less expensive than RNA-based tests, they are also able to detect and quantify HIV infection in infants more reliably and at a much younger age.  

This World AIDS Day, as Cavidi celebrates the 25th Anniversary of our RT-technology, I’m pleased to report that we are making steady progress on three fronts to address the challenges above.  First, we continue to support the increasing uptake of our manual ExaVir Load HIV viral load monitoring test which is increasing access to affordable HIV viral load testing around the world.  Second, we have made excellent progress developing a new automated platform for near patient HIV viral load monitoring. The platform design is now entering final stages of prototype development and testing. And third, over this past year we have initiated further studies into the development of an RT-based EID test. I look forward to sharing more details on these exciting developments over the next year.

New challenges require new solutions. As we enter the decade of diagnostics I hope to see a new gold standard emerge that will make HIV viral load testing more accessible and reliable. My team will do their part as they continue to bring innovative RT-based diagnostics to the world in 2013 and beyond. 

 John Reisky de Dubnic




HIV Viral load monitoring: from patient to public health issue

Amazing strides have been made in providing access to Antiretroviral Therapy (ART) in resource-limited settings. In 2011, around
8 million HIV-infected patients living in low- and middle-income countries have access to ART compared to just 400,000 a decade a go. Greater access to Antiretroviral drugs (ARVs) is good news, but it has magnified the need for HIV viral load monitoring to properly administer these drugs. A recent Médecins Sans Frontières (MSF) review of data from 12 low- and middle-income countries found that only 2% of patients had ever received a HIV viral load test result, no less received them every 6-months as recommended by the World Health Organization (WHO).

One Hope by Joe Average was used for the XI International AIDS Conference in Vancouver in 1996The direct benefits of HIV viral load testing to the patient are well documented in terms of better outcomes with decreased mortality. That’s why HIV viral load testing has long been a standard part of treatment in middle- to upper-income nations. But if we look beyond the patient, there is an equally compelling public health case to be made for ensuring access to HIV viral load testing in the low- and middle-income countries where the vast majority of HIV patients live. Here are four ways HIV viral load testing protects the public as well as the patient. 

 1. Help clinical resources go further by targeting counseling where it is needed. Some patients will take their medication as instructed – many will not. Noncompliant patients will usually show elevated viral activity which can lead to increases in treatment failure, transmission, comorbidity, drug resistance, and mortality. Counseling has been found to be very effective at helping with adherence issues but is labor intensive.  This can be an enormous strain affecting the entire clinic. With HIV viral load monitoring the clinic can identify noncompliant patients early and more efficiently target counseling only to those who need it. 

 2. Reduce treatment costs by helping less-expensive first-line ART last longer.  HIV mutates at such a remarkable rate that it is a foregone conclusion the virus will eventually be able to resist first-line treatment. The only question is when. If proper concentrations of the drugs are not properly maintained in the blood it makes this job a lot easier for the virus and thus will lead to treatment failure sooner. Monitoring viral load helps identify viral activity and address it before the treatment fails and the patient needs to be moved to a new treatment (if available).  Without viral load measurement, doctors can also misattribute patient symptoms to treatment failure and switch them before it is required. Since first-line ART is always cheaper than second-line treatment (in some cases one-quarter the price), keeping patients on first-line treatment for as long as possible helps resources go further. 

3. Reduce the spread of HIV.  Studies have found that transmission among HIV-infected persons with a viral load below 1,500 copies/ml is rare.  Put simply, if there is no virus circulating in the patient’s blood, then they are unlikely to spread the disease.  So managing HIV viral load can, in itself, contribute to prevention. But you can’t manage what you can’t measure. This is where HIV viral load monitoring contributes. A mathematical model published in the AIDS journal this year demonstrated that routine virological monitoring combined with ART can lead to a 31% reduction in HIV transmission. 

 4. Combat the global problem of HIV drug-resistance. If HIV is allowed to remain active in the presence of drugs meant to suppress it, then it is just a matter of time before it will produce a viable mutation that will be resistant to the drug. We are already seeing this. A 2010 study in resource-limited settings found that in the absence of HIV viral load monitoring, the incidence of drug-resistant mutations following treatment failure is high.  Of course this causes secondary resistance in these patients. But there’s a knock-on effect in that these resistant patients begin spreading a strain of HIV to others that drugs can’t treat. MSF reports that primary resistance in sub-Saharan Africa is already at 5.6% overall. If we look at countries where ART have been dispensed without HIV viral load monitoring for 10 years or longer we see a rate of 12%.  Worse still, the drug-resistant mutations that are being found in newly infected people who have never been on treatment are resistant to both first- and second-line drugs. That’s a trend that could unravel much of the progress made over the last 20 years in the battle against HIV. 

When we look at HIV viral load monitoring from a public health perspective it becomes clear that the issues above are not limited to low- and middle-income countries. First, because any HIV viral load monitoring solution that is inexpensive enough to be viable in resource-limited settings could lower the cost of HIV treatment for any healthcare system. Secondly, because issues like the spread of HIV infection and drug resistance know no borders. HIV/AIDS is a global problem and affordable HIV viral load monitoring is an important part of the solution whether you are in Nairobi, New York, Melbourne, Lusaka, London, Harare or Hong Kong. 

 As access to ARVs grows across low- and middle-income regions, so does the public health imperative to dispense those drugs in a responsible manner with regular HIV viral load monitoring of patients.  As MSF put it, “Funding the implementation of viral load should not be seen as a luxurious and avoidable expense, but should rather be recognized as a necessary and potentially cost-saving addition to current international commitments to scaling up treatment.”  Today, Cavidi and others have the technology to address this public health issue and provide inexpensive, near-patient HIV viral load monitoring where ever it is needed. Doing so will not only serve the patient but protect the public. All we need is the collective will to make it happen. One more reason why the time for HIV viral load testing is now. 


John Reisky de Dubnic



Further reading:

  • Aghokeng AF, Kouanfack C, Laurent C, Ebong E, Atem-Tambe A, Butel C, Montavon C, Mpoudi-Ngole E, Delaporte E, Peeters M: Scale-up of antiretroviral treatment in sub-Saharan Africa is accompanied by increasing HIV-1 drug resistance mutations in drug-naive patients. AIDS 2011, 25: 2183 –2188.
  • Estill J, Aubriere C, Egger M, Johnson L, Wood R, Garone D, Gsponer T, Wandeler G, Boulle A, Davies M-A, Hallett T, Keiser O: Viral load monitoring of antiretroviral therapy, cohort viral load and HIV transmission in Southern Africa: A mathematical modelling analysis. AIDS 2012, 26: 1413.
  • Hamers RL, Wallis CL, Kityo C, Siwale M, Mandaliya K, Conradie F, Botes ME, Wellington M, Osibogun A, Sigaloff KCE, Nankya I, Schuurman R, Wit FW, Stevens WS, van Vugt M, de Wit TFR: HIV-1 drug resistance in antiretroviralnaive individuals in sub-Saharan Africa after rollout of antiretroviral therapy: a multicentre observational study. Lancet Infect Dis 2011, 11: 750 –759.
  • Lynen L, Van Griensven J, Elliott J: Monitoring for treatment failure in patients on first-line antiretroviral treatment in resource-constrained settings. Curr Opin HIV AIDS 2010, 5: 1–5.
  • Médecins Sans Frontières: Undetectable – How Viral Load Monitoring Can Improve HIV Treatment in Developing Countries, July 2012
  • Murtagh M: UNITAID HIV/AIDS Diagnostic Landscape 2nd Edition. 2012.
  • Quinn T, Wawer M, Sewankambo N: Viral Load and Heterosexual Transmission of Human Immunodeficiency Virus Type 1. N Engl J Med 2000, 342: 921–929.