HIV drug resistance surveillance concept notes

In 2004, WHO in collaboration with HIVResNet developed a global strategy for surveillance and monitoring of HIV drug resistance (HIVDR).

As part of the strategy, WHO developed surveillance methods to assess the prevalence of HIVDR.

The current concept notes are available below:

1. HIVDR in adult populations starting ART (pre-treatment HIVDR) and HIVDR in adult populations receiving ART (acquired HIVDR)

These two new surveillance methods replace a previous prospective approach. The surveillance method for pre-treatment HIVDR yields a nationally representative estimate of HIVDR in populations initiating ART. The surveillance method for acquired HIVDR yields a nationally representative estimate of viral load suppression and acquired HIVDR. The methods provide results relevant for ART programme level decision making and have built-in flexibility for country adaptation. WHO and partners are working to develop a concept note to assess acquired HIVDR in paediatric populations receiving ART.

National surveys should be undertaken using the new concept notes.

Download current HIVDR surveillance concept notes

WHO has developed a series of Excel-based sample size calculators to assist countries in designing pre-treatment HIV drug resistance (PDR) surveys and acquired HIV drug resistance (ADR) surveys. These calculators yield sample size calculations consistent with the WHO methodology described in the PDR and ADR concept notes. The calculators are divided into three groups pertaining to the type of survey that will be designed: (1) PDR survey only, (2) ADR survey only, and (3) concurrent PDR and ADR survey. Each calculator group is contained within a separate Excel file. Each group includes an introductory guide (START HERE) and a series of calculators. Please read the introductory guide to determine which calculator is most appropriate for your survey type.

2. HIVDR in infants less than 18 months of age

Surveillance of HIVDR among HIV-infected children less than 18 months of age is important for improving health outcomes and minimizing HIVDR in this population. This survey method uses remnant dried blood spot specimens from a representative sample of children less than 18 months of age being tested for early infant diagnosis. HIVDR genotyping results generated from this survey will support choice of first-line ART in this population.


3. HIVDR in recently infected populations (transmitted HIV drug resistance)

The survey method using truncated sequential sampling which provided a prevalence classification of transmitted HIVDR in a specific geographic area is no longer recommended by WHO. WHO and partners are working to develop a new concept note which will provide a national statistic of transmitted HIVDR in recently infected populations. The concept note will be posted as soon as it becomes available.