Table 1. Characteristics of liquid and lyophilized influenza vaccine formulations.
| Liquid | Lyophilized | |||||
| Vaccine | Size (nm) | PDI | Size (nm) | PDI | HA1 recovery (%) | Antigenic recovery (%) |
| WIV | 137±1 | 0.07 | 146±3 | 0.09 | 137±11 | 111±1 |
| Virosome | 131±2 | 0.13 | 151±9 | 0.24 | 110±9 | 118±4 |
| Split | 520±14 | 0.63 | 150±4 | 0.43 | 115±4 | 95±7 |
| Subunit | 103±2 | 0.41 | 131±4 | 0.32 | 115±11 | 100±2 |
Size and polydispersity index (PDI) are shown for liquid formulations and reconstituted lyophilized formulations. Recovery of HA1 and antigenicity of lyophilized vaccines are shown as a percentage of vaccines before freeze-drying. Data represent mean ± SD; n = 3.