Table 3.
Vaccine characteristics of included studies (N=41)
| Frequency* | % of vaccines (N=102) | ||
| Vaccine platforms | Egg based | 47 | 46% |
| Cell based | 5 | 5% | |
| Recombinant | 4 | 4% | |
| Not applicable | 2 | 2% | |
| Not reported | 44 | 43% | |
| Adjuvant | Yes | 26 | 25% |
| No/not applicable | 76 | 75% | |
| Dosage of HA/strain | Standard dosage | 64 | 63% |
| High dosage | 23 | 23% | |
| Other | 10 | 10% | |
| Not applicable | 5 | 5% | |
| Frequency* | % of arms (N=98) | ||
| Dose frequency | Single dose | 89 | 91% |
| Two doses | 3 | 3% | |
| Not reported | 5 | 5% | |
| Not applicable | 1 | 1% | |
| Duration between the doses | 4 weeks | 2 | 2% |
| 3 weeks | 1 | 1% | |
| Not reported | 5 | 5% | |
| Not applicable | 90 | 92% | |
The term ‘other’ in the vaccine name indicates that there are varying dosages available for different strains or includes the dosage of recombinant vaccines. As such, it is not categorised as standard dose nor high dose as per guidelines.
*It is possible for one study to report multiple treatment arms utilising different platforms or dosages. Therefore, the total frequency may not be equal to the actual number of studies.