Practical methods to measure the potency of influenza vaccines are needed as 
alternatives for the standard single radial immunodiffusion (SRID) assay. 
VaxArray assays for influenza hemagglutinin (HA) and neuraminidase (NA) have 
been developed to address this need. In this report, we evaluate the use of 
these assays to assess the potency of HA and NA of an A/H3N2 subunit vaccine by 
determining the correlation between the amounts measured by VaxArray and the 
immunogenicity in mice. The antibody response after one and two doses of five 
formulations of the vaccine ranging from 5 µg/mL to 80 µg/mL of HA, was measured 
by hemagglutination inhibition (HAI) and neuraminidase inhibition (NAI) assays. 
For hemagglutinin, vaccine potency determined by VaxArray was equivalent to 
potency measured SRID and these amounts were predictive of immunogenicity, with 
excellent correlation between potency measured by VaxArray and the HAI geometric 
mean titers (GMT). Likewise, the amount of NA measured by VaxArray was 
predictive of the NAI GMT. The VaxArray NA assay reported non-detectable levels 
of intact NA for a sample that had been heat degraded at 56 °C for 20 h, 
demonstrating that the assay measures the native, active form of NA. Similarly, 
the HA potency measured by VaxArray in this heat-treated sample was very low 
when a monoclonal antibody was used to detect the amount of antigen bound. 
Importantly, the force degraded sample induced low HAI titers and the NAI titers 
were not measurable, supporting the conclusion that the VaxArray HA and NA 
assays measure the immunogenic forms of these A/H3N2 antigens. This study 
indicates that VaxArray assays can be used to assess the potency of HA and NA 
components in influenza vaccines as a proxy for immunogenicity.