Table 2. Quantification of NP in influenza vaccines by mass spectrometry.

For each vaccine, the proteins were quantified by spectral count of related strains indicated in the package insert. Because commercial vaccines indicate primarily micrograms of HA content, mass spectrometry–quantitated NP spectral counts were expressed in relation to HA spectral count. NP content in seasonal split-vaccines was about 3 to 12 times greater than that detected in seasonal subunit vaccines, with the exception of Fluvirin. Testing of Focetria by mass spectrometry demonstrated NP-to-HA ratios similar to those seen with Agrippal and Chiromas. NP content of the A(H1N1)pdm09 split-virion vaccines Arepanrix and Pandemrix was about 2.9 and 3.7 times greater, respectively, than that detected in the A(H1N1)pdm09 subunit vaccine Focetria.

VaccineNP (spectra
count)
HA (spectra
count)
NP per HA (ratio)
Fluzone
trivalent
3282581.27
Fluzone
quadrivalent
3203350.96
Fluarix
trivalent
1462820.52
Fluarix
quadrivalent
1421870.76
Afluria
trivalent
2126040.35
Agrippal
trivalent
433930.11
Chiromas
trivalent
464520.10
Fluvirin
trivalent
3263410.96
Focetria
lot 2009
634670.13
Focetria
lot 2010
604980.12
Arepanrix
2010
4887030.69
Pandemrix
2009
4464650.96