HIV This Week

Bennett D, Myatt M, Bertagnolio S, Sutherland D, Gilks C. Recommendations for surveillance of transmitted HIV drug resistance in countries scaling up antiretroviral treatment. Antivir Ther 2008; Supplement 2: 25–36.

The World Health Organization (WHO) HIV drug resistance threshold survey method was developed for surveillance of transmitted HIV drug resistance in resource-limited countries. The method is being implemented with minimal resources as a routine public health activity to produce comparable results in multiple countries and areas within countries. Transmitted drug resistant HIV strains will be seen first in cities or health districts where antiretroviral treatment has been widely available for years. WHO recommends countries begin surveillance in these areas. Each survey requires <=47 specimens from individuals consecutively diagnosed with HIV to categorize resistance to each relevant drug class as <5%, 5–15% or >15%. Use of routinely collected information and remnant specimens is recommended to minimize costs. Site and individual eligibility criteria are designed to minimize inclusion of antiretroviral drug-experienced individuals and individuals infected before antiretroviral treatment was available. Surveys have been implemented in 21 countries. In this supplement, seven countries report results of <5% transmitted HIV drug resistance in areas where antiretroviral treatment has been available for the longest time period. The main challenges in implementation are acquiring sufficient numbers of eligible specimens and optimizing specimen handling. The WHO HIV drug resistance threshold survey method is feasible in resource-limited countries and produces information relevant to antiretroviral treatment and drug resistance prevention planning.

Editors’ note: This supplement contains reports of HIV drug resistance surveillance from seven countries ( Ethiopia, Malawi, Swaziland, Tanzania, Vietnam, South Africa, and Thailand) along with methodological articles explaining the threshold survey analysis method. This method requires minimal infrastructure and provides important information to limit the emergence and transmission of resistance in resource-limited settings.

Malawi started rapid scale-up of antiretroviral therapy in 2004 and by December 2006 had initiated over 85,000 patients on treatment. Early warning indicator reports can help to minimize the risk of emerging drug resistance. Data collected during the routine quarterly supervision of 103 public sector sites was used to compile the first early warning indicator report for HIV drug resistance in Malawi, reflecting outcomes for October to December 2006. All sites reach the World Health Organization (WHO) targets for prescribing practices and drug supply continuity. The target for adherence was achieved by 85% of sites and 84% achieved the target for minimizing treatment defaults; however, less than half of all sites reach the WHO target for patient retention. In conclusion, these results emphasize the importance of defaulter tracing and initiating treatment earlier in the course of HIV infection. As part of a comprehensive HIV drug resistance monitoring programme, the Ministry of Health plans for on-going tracking of these indicators, as well as special data collection from the private sector. Plans are also underway to gather information on other recommended indicators that are not collected during routine supervision.

Editors’ note: In Malawi, data on programmatic factors associated with an increased risk of drug resistance such as patient adherence, prescribing practices, continuity of drug supply, and patient outcomes are reviewed with site personnel during routine quarterly supervision visits. National patient mastercards (the patient record) and patient antiretroviral registers are complimented by pharmacy registers. With monthly targets for new patients starting HIV treatment set nationally, drug procurement can be accurately estimated and drugs reallocated if necessary to prevent the stock-outs that are a prominent cause of drug resistance.