Dataset Information

The emergence of HIV transmitted resistance in Botswana: "when will the WHO detection threshold be exceeded?".

ABSTRACT:

Background

The Botswana antiretroviral program began in 2002 and currently treats 42,000 patients, with a goal of treating 85,000 by 2009. The World Health Organization (WHO) has begun to implement a surveillance system for detecting transmitted resistance that exceeds a threshold of 5%. However, the WHO has not determined when this threshold will be reached. Here we model the Botswana government's treatment plan and predict, to 2009, the likely stochastic evolution of transmitted resistance.

Methods

We developed a model of the stochastic evolution of drug-resistant strains and formulated a birth-death Master equation. We analyzed this equation to obtain an analytical solution of the probabilistic evolutionary trajectory for transmitted resistance, and used treatment and demographic data from Botswana. We determined the temporal dynamics of transmitted resistance as a function of: (i) the transmissibility (i.e., fitness) of the drug-resistant strains that may evolve and (ii) the rate of acquired resistance.

Results

Transmitted resistance in Botswana will be unlikely to exceed the WHO's threshold by 2009 even if the rate of acquired resistance is high and the strains that evolve are half as fit as the wild-type strains. However, we also found that transmission of drug-resistant strains in Botswana could increase to approximately 15% by 2009 if the drug-resistant strains that evolve are as fit as the wild-type strains.

Conclusions

Transmitted resistance will only be detected by the WHO (by 2009) if the strains that evolve are extremely fit and acquired resistance is high. Initially after a treatment program is begun a threshold lower than 5% should be used; and we advise that predictions should be made before setting a threshold. Our results indicate that it may be several years before the WHO's surveillance system is likely to detect transmitted resistance in other resource-poor countries that have significantly less ambitious treatment programs than Botswana.

SUBMITTER: Vardavas R

PROVIDER: S-EPMC1764713 | biostudies-literature | 2007 Jan

REPOSITORIES: biostudies-literature

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Publications

The emergence of HIV transmitted resistance in Botswana: "when will the WHO detection threshold be exceeded?".

Vardavas Raffaele R Blower Sally S

PloS one 20070117 1

<h4>Background</h4>The Botswana antiretroviral program began in 2002 and currently treats 42,000 patients, with a goal of treating 85,000 by 2009. The World Health Organization (WHO) has begun to implement a surveillance system for detecting transmitted resistance that exceeds a threshold of 5%. However, the WHO has not determined when this threshold will be reached. Here we model the Botswana government's treatment plan and predict, to 2009, the likely stochastic evolution of transmitted resist ...[more]

PMID: 17225857

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Project description:BackgroundThe aim of this study is to analyse the prevalence of transmitted drug resistance, TDR, and the impact of TDR on treatment success in the German HIV-1 Seroconverter Cohort.MethodsGenotypic resistance analysis was performed in treatment-naïve study patients whose sample was available 1,312/1,564 (83.9% October 2008). A genotypic resistance result was obtained for 1,276/1,312 (97.3%). The resistance associated mutations were identified according to the surveillance drug resistance mutations list recommended for drug-naïve patients. Treatment success was determined as viral suppression below 500 copies/ml.ResultsPrevalence of TDR was stable at a high level between 1996 and 2007 in the German HIV-1 Seroconverter Cohort (N?=?158/1,276; 12.4%; CI(wilson) 10.7-14.3; p(for trend)?=?0.25). NRTI resistance was predominant (7.5%) but decreased significantly over time (CI(Wilson): 6.2-9.1, p(for trend)?=?0.02). NNRTI resistance tended to increase over time (NNRTI: 3.5%; CI(Wilson): 2.6-4.6; p(for trend)=?0.07), whereas PI resistance remained stable (PI: 3.0%; CI(Wilson): 2.1-4.0; p(for trend)?=?0.24). Resistance to all drug classes was frequently caused by singleton resistance mutations (NRTI 55.6%, PI 68.4%, NNRTI 99.1%). The majority of NRTI-resistant strains (79.8%) carried resistance-associated mutations selected by the thymidine analogues zidovudine and stavudine. Preferably 2NRTI/1PIr combinations were prescribed as first line regimen in patients with resistant HIV as well as in patients with susceptible strains (susceptible 45.3%; 173/382 vs. resistant 65.5%; 40/61). The majority of patients in both groups were treated successfully within the first year after ART-initiation (susceptible: 89.9%; 62/69; resistant: 7/9; 77.8%).ConclusionOverall prevalence of TDR remained stable at a high level but trends of resistance against drug classes differed over time. The significant decrease of NRTI-resistance in patients newly infected with HIV might be related to the introduction of novel antiretroviral drugs and a wider use of genotypic resistance analysis prior to treatment initiation.

Dataset Information

The emergence of HIV transmitted resistance in Botswana: "when will the WHO detection threshold be exceeded?".

Background

Methods

Results

Conclusions

Publications

The emergence of HIV transmitted resistance in Botswana: "when will the WHO detection threshold be exceeded?".

Similar Datasets

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