HIV drug resistance in Africa

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In 2016, the WHO guidelines on the use of antiretroviral drugs for treating and preventing HIV infection were updated [1]. In these guidelines, WHO recommend antiretroviral therapy (ART) for all people living with HIV. Universal access to HIV treatment is mandatory in order to achieve the goal of United Nations AIDS Program to end the HIV/AIDs epidemic as a public health threat by 2030. However, universal access to treatment is not a sufficient tool to end HIV epidemic if it is not accompanied by the ability to monitor its effectiveness and to make the appropriate changes in the antiretroviral regimen when it fails. In these guidelines, routine viral load is recommended as the preferred monitoring approach to diagnose and confirm treatment failure. Unfortunately, there are too many settings in poor-resource countries in which this essential measure to fight against AIDS is still not available. The potential risk of universal treatment without monitoring viral load or testing genotypic resistance is to create a new epidemic of drug-resistant HIV. Nossa Senhora da Paz hospital is located in Cubal, a rural setting of sub-Saharan Africa, in the province of Benguela in Angola. It is a private nonprofit hospital run by Sisters of the Company of Santa Teresa de Jesus and belongs to the national network of hospitals. Established in 2005, this was one of the first rural clinics accredited to be a Care and Treatment Centre of the National AIDS Control Program in the country, and over 1500 patients have been enrolled into care since its foundation. Routine CD4+ lymphocyte count is performed before treatment initiation and periodically every 3–4 months. Viral load determination is not available. In patients with suspected failure to ART, samples of dried blood spot specimens (DBSS) were collected to determine HIV viral load. Samples were analyzed in the Microbiology Department of Hospital Vall d’Hebron in Barcelona. RNA extraction and viral load determination were performed with NucliSENS Easy Q v2.0 system. A threshold of 1000 copies/ml has been used to define virological failure. For genotypic resistance testing on DBSS, nucleic acids were extracted using the same method. Relevant drug-resistant mutations (DRMs) in the retrotranscriptase, protease, and integrase were identified by deep sequencing in a 454 GS Junior System (Roche Diagnostics, Mannheim, Germany). Results were analyzed by DeepChek HIV v1.4 (ABL and Therapy Edge) using a 1% frequency threshold for variant detection. Genotype interpretation was performed according to the HIV drug resistance database from Stanford University. In September 2016, 606 HIV-infected patients (432 women and 174 men) were actively controlled in the outpatient clinic of hospital Nossa Senhora da Paz. Overall, 505 (83%) of the patients were receiving ART, most of them a first-line regimen based on non-nucleoside reverse transcriptase inhibitors. Seventeen patients were receiving a second-line regimen with two nucleoside reverse transcriptase inhibitors and lopinavir/ritonavir. In seven of these 17 patients, clinical or immunological failure was suspected. A genotypic resistance test was performed in seven patients with suspicion of clinical and/or immunological failure to first-line regimen (patients 1–3) or second-line regimen (patients 4–7). Table 1 shows the results of the genotype resistance tests performed.Table 1: Genotypic resistance tests of patients with first or second-line ART regimen failure.In our experience, we have corroborated that the lack of routine viral load monitoring leads to a late diagnosis of virological failure. The consequence of late diagnosis of virological failure is that DRMs accumulate, as we can observe in our first three patients with failure to first-line regimen. In the 2LADY-ANRS 12169 trial, conducted in Cameroon, Senegal, and Burkina Faso, 98.7% of the patients were resistant to at least one of the first-line drugs, and 40.6 and 55.8% were resistant to two or three drugs of their ongoing first-line regimen [2]. The prevalence of resistance increased with time on ART, from 8% in the 6–12-month group to 27.1% in the above 72-month group [3]. More worrying, if possible, is the situation in HIV-infected children and adolescents. Among 213 children on ART for a median of 4.3 years in rural Tanzania, 25.4% had virological failure. ART-associated DRMs were identified in 90%, with multiclass resistance in 79% [4]. This situation is similar to what occurs in other settings in sub-Saharan Africa [5–7]. A matter of concern is the detection of major mutations to integrase inhibitors in patients 2 and 3. A possible explanation for these cases is the transmission of virus with primary resistance to integrase inhibitors. This observation requires further monitoring in order to detect primary resistance to integrase inhibitors in settings with no availability of these drugs. The delay in diagnosis of failure to first-line ART regimens and the accumulation of resistance mutations may lead to a loss of efficacy of the second-line regimens. In sub-Saharan Africa in patients treated with a protease inhibitor-based second-line regimen and viral load at least 1000 copies/ml, 22 of 32 (69%) harbored DRMs, and seven of 32 (22%) harbored protease inhibitor resistance [8]. This probably explains the low efficacy of protease inhibitor-based second-line regimens observed in the 2LADY ANRS 12169 trial in which only 37.7% of patients with viral load above 100 000 copies/ml at failure of first-line regimen had a viral load below 50 copies/ml at week 48 [9]. Finally, we can expect that transmitted drug resistance may increase in the following years in resource-limited countries. As an example of this situation is the alarmingly high rate of drug resistance observed among newly diagnosed HIV-infected children in the National Prevention of Mother-to-child Transmission Program in Togo. Overall, 121 of 201 (60.2%) newly diagnosed children had detectable DRMs [10]. In summary, it is necessary to extend the capacity to determine viral load in poor-resource settings in order to detect earlier virological failure. Otherwise, it is mandatory to provide national programs with new families of antiretroviral drugs such as integrase inhibitors. Resistance to antiretroviral drugs in developing settings constitutes a serious health threat to achieve the aim to eradicate HIV infection [11,12]. The threat of resistance is here and we must face it without delay. Acknowledgements M.M. and V.F. had full access to all the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis.