Surveillance of transmitted HIV drug resistance with the World Health Organization threshold survey method in Lilongwe, Malawi

Abstract

Background: Malawi started rapid scale-up of antiretroviral therapy (ART) in 2004 and by December 2006 had initiated 81,821 patients on treatment in the public sector. Owing to capacity constraints, standard patient care, treatment initiation and follow up are based on World Health Organization (WHO) clinical staging and do not provide laboratory monitoring to assess treatment failure.

Methods: To monitor possible transmission of HIV drug resistance (HIVDR) an HIVDR threshold surveillance based on the WHO guidelines was implemented in Malawi. Anonymous dried blood specimens were collected from routine blood samples of HIV-positive women attending primagravida antenatal care and aged <25 years.

Results: Of 59 samples tested, 54 were successfully amplified indicating good specimen quality and processing. The WHO protocol algorithm to classify the prevalence of transmitted drug resistance in the site sample only required the genotyping of 34 of the samples. None of the major drug resistance mutations on the WHO surveillance list were found in these 34 specimens.

Conclusions: Malawi HIVDR transmission can be classified as <5% for all relevant drugs and drug classes in this population. On the basis of the very positive experience of this survey, an expanded HIVDR surveillance system will be implemented to inform the ART program as it continues to scale-up.