A study published in the Journal of Antimicrobial Chemotherapy has reported that antiretroviral therapy (ART) is currently failing in one quarter of the patients receiving this treatment in Mozambique, one of the countries with the highest HIV prevalence in the world. These findings confirm the need to monitor the viral load in HIV patients in order to ensure timely detection of treatment failure so that the necessary changes can be made in treatment to slow the progression of the disease and prevent the selection of drug-resistant virus that may spread to the rest of the population. The study is the result of a strategic collaboration between ISGlobal, the IrsiCaixa AIDS Research Institute and the Manhiça Health Research Centre (CISM).
The study was carried out in the Manhiça district of Mozambique, one of the regions with the highest prevalence of HIV in Africa. Since 2004, there has been free access to antiretroviral drugs in this district where 40% of the population is currently infected with the virus. The authors of the new study found that 24% of the patients on ART in Manhiça have high viral loads and that 89% of these patients have developed resistance to the most commonly used antiretroviral drugs. The presence of high viral loads indicates that the virus is continuing to replicate despite treatment.
"The findings are very worrying," says Maria Rupérez, the study's lead author, "If the current treatment is not working, these patients will have to be switched to other drugs, but the alternatives are more expensive not always available". Moreover, there is also a danger that resistant strains of the virus will spread to the rest of the population, aggravating the situation and jeopardizing the control of the HIV epidemic in Africa.
Since 2001, large-scale distribution of antiretroviral drugs and the use of standardised and simplified protocols have made it possible to treat more than 9 million people living with HIV in developing countries, particularly sub-Saharan Africa. While this increase in the number of people receiving ART is a very positive development, it also brings new challenges. Without proper monitoring, patients in whom the drugs fail to stop the replication of the virus—either because of poor adherence to treatment or because the virus has developed resistance—will continue to receive the same drug while maintaining high viral loads, a situation that facilitates the accumulation of resistant strains and more rapid progression of the disease.
The World Health Organisation (WHO) recommends virologic monitoring to ensure that treatment failure is identified promptly and the patient can be switched to a different therapy. However, the reality is that viral load testing is not carried out in many health care centres in developing countries because of a lack of technical and economic resources. According to Roger Paredes, the principal investigator on the study, the solution is to facilitate access to a wider range of treatments and to ensure "affordable access to the new rapid viral load tests that can detect early virologic failure and are suitable for use in the health centres, as recommended by WHO". In his view, "The large-scale distribution of a simplified viral load test in developing countries would not only be a major step in the control of HIV in these patients, but would also help to prevent the spread of resistance to the rest of the population."
Reference: María Rupérez, Christian Pou, Sonia Maculuve, Samandhy Cedeño,Leopoldina Luis, Judith Rodríguez, Emilio Letang, José Moltó, Eusébio Macete, Bonaventura Clotet, Pedro Alonso, Clara Menéndez, Denise Naniche, and Roger Paredes. Determinants of virological failure and antiretroviral drug resistance in Mozambique. J. Antimicrob. Chemother. first published online June 16, 2015.