Transmitted Drug Resistance Rate Remains Below 5% in South Africa

by Mark Mascolini - Analysis of South Africans with newly diagnosed, untreated HIV infection indicates low levels of transmitted antiretroviral-resistant HIV across the country through 2010 and no evidence of transmitted drug-resistant HIV in rural KwaZulu Natal

Monitoring regional levels of transmitted antiretroviral-resistant HIV is crucial to planning treatment strategies. In countries with high rates of transmitted resistant virus, authorities usually recommend routine genotyping of virus from people starting their first antiretroviral regimen to ensure that they take drugs to which their virus remains sensitive.

This analysis of transmitted drug resistance rates in South Africa involved several methods: (1) a literature review, (2) analysis of 72 sequences from newly diagnosed people in rural KwaZulu Natal identified in the Africa Centre's 2010 HIV surveillance round, and (3) publicly available data on transmitted drug resistance from Genbank.

Viral samples collected in 2010 from newly infected people in rural KwaZulu Natal yielded no evidence of transmitted drug resistance. KwaZulu Natal province has the highest HIV prevalence in South Africa, 22.3% among women and 11.5% among men.

Among 1618 viral samples collected in 10 datasets from 2000 through 2010 across South Africa, the rate of transmitted drug resistance peaked at 6.67% (95% confidence interval 3.09% to 13.79%) in 2002. In subsequent years, the rate of transmitted drug resistance always lay below 5%, the World Health Organization cutoff for low-level transmitted resistance. After 2002, there was no statistically significant increase in transmitted drug resistance across South Africa.

The most frequently identified resistance mutations were those associated with nonnucleoside reverse transcriptase inhibitors the K103N mutation, followed by Y181C and Y188C/L. Five viral sequences analyzed had multiple mutations associated with nonnucleoside resistance.

'In Southern Africa as antiretroviral therapy access and treatment programs grow,' the authors caution, 'it is critical to maintain surveillance among recent seroconverters, treatment-naive and treated populations.'

They add that 'programs, covering well-defined geographic areas and populations, minimize the biases inherent in transmitted drug resistance surveillance and provide guidance in implementing risk reduction and secondary prevention to maintain the effectiveness of first-line treatment.'

Source: Justen Manasa, David Katzenstein, Sharon Cassol, Marie-Louise Newell, Tulio de Oliveira. Primary drug resistance in South Africa: data from 10 years of surveys. AIDS Research and Human Retroviruses. Online ahead of print. doi:10.1089/AID.2011.0284.

News date: 2012-03-05


Publication cited

Evaluation of tuberculosis diagnostics: establishing an evidence base around the public health impact. Lessells RJ, Cooke GS, Newell ML, Godfrey-Faussett P, J Infect Dis (2011), 204:S1187-95.

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