The new ECDC technical report describes the first European external quality assessment (EQA) exercise for antiviral drug susceptibility testing of influenza viruses.
Twenty different laboratories from 16 European countries participated in the exercise carried out during winter 2010/11. Participants tested samples of recent influenza A and B viruses containing substitutions known to confer resistance to antiviral drugs. In addition, they provided an interpretation of variations in the results for genotypic and phenotypic testing in terms of virus susceptibility to antiviral drugs.
The results of the exercise show good results from the genotypic detection of the H275Y mutation in influenza A(H1N1)pdm09 virus. The proficiency for detection of a mixture of resistant and sensitive A(H1N1)pdm09 viruses was lower. Areas of difficulty included influenza A(H1N1)pdm09 mixture analysis, analysis of NAI-resistant H3N2 and influenza B virus. Variation between genotypic and phenotypic susceptibility testing was observed.
The report concludes that the following strategies would help to improve consistency:
- provision of guidelines on the interpretation of resistance mutations and phenotyping results;
- harmonisation of baseline values;
- provision of a reference set of viruses.
Future capacity building should focus on the development of widespread capability for genotypic and phenotypic detection of oseltamivir resistance in A(H1N1)pdm09 and other human influenza viruses.
The results of this exercise will be used to guide the development of the network of laboratories and promote harmonisation of antiviral susceptibility testing, data interpretation and reporting.
Read the full report