Laboratory methodologies for testing the antiviral susceptibility of influenza viruses

November 2012

The need for surveillance of antiviral susceptibility of influenza viruses has grown in recent years. The laboratory methodologies described below have been developed and reviewed by an Expert Working Group on Antiviral Susceptibility for the WHO Global Influenza Surveillance and Response System (GISRS). They are intended for National Influenza Centres in GISRS and other laboratories that test for influenza antiviral susceptibility.

M2 ion channel inhibitor

• Current approaches to M2 inhibitor resistance testing

Neuraminidase inhibitor (NAI)

• Overview of amino acid substitutions in influenza neuraminidase associated with resistance or reduced susceptibility to NAIs
• Genotyping: molecular-based assays
• Phenotyping: neuraminidase inhibition assays

Reference viruses for validation and controls

• Reference viruses for NAI susceptibility assays