Table 3.
Antibody responses to four types of influenza strains.
| SARS-CoV-2 + IIV4/PPV23 group | SARS-CoV-2 + PPV23/IIV4 group | SARS-CoV-2/IIV4+PPV23 group | P value | 95% CI | Non-inferiority* | ||||
|---|---|---|---|---|---|---|---|---|---|
| Group 1 | Group 2 | Group 3 | Group 1&2 | Group 3&2 | Group 1&2 | Group 3&2 | Group 1&2 | Group 3&2 | |
| A/H1N1 | |||||||||
| Seropositivity-BI [n (%)] | 29.32 | 25.76 | 32.46 | 0.432 | 0.145 | ||||
| GMT-BI | 17.23 | 16.56 | 17.81 | 0.732 | 0.509 | ||||
| Seropositivity [n (%)] | 96.86 | 94.95 | 95.29 | 0.343 | 0.877 | ||||
| Seroconversion [n (%)] | 87.43 | 90.91 | 85.34 | 0.270 | 0.089 | -3.47(-9.65,2.7) | -5.57(-11.99,0.85) | Yes | No |
| GMT | 475.30 | 488.80 | 307.50 | 0.843 | 0.001 | 0.97(0.74,1.28) | 0.63(0.48,0.83) | Yes | No |
| A/H3N2 | |||||||||
| Seropositivity-BI [n (%)] | 36.65 | 35.86 | 43.46 | 0.871 | 0.126 | ||||
| GMT-BI | 26.45 | 26.37 | 28.65 | 0.967 | 0.174 | ||||
| Seropositivity [n (%)] | 98.95 | 98.48 | 97.91 | 0.682 | 0.668 | ||||
| Seroconversion [n (%)] | 86.91 | 80.30 | 65.97 | 0.079 | 0.001 | 6.61(-0.71,13.93) | -14.33(-23.04,-5.63) | Yes | No |
| GMT | 223.40 | 177.70 | 129.60 | 0.028 | 0.001 | 1.26(1.03,1.54) | 0.73(0.6,0.88) | Yes | Yes |
| B/Victoria | |||||||||
| Seropositivity-BI [n (%)] | 35.08 | 41.92 | 46.60 | 0.166 | 0.353 | ||||
| GMT-BI | 24.96 | 28.38 | 30.36 | 0.133 | 0.426 | ||||
| Seropositivity [n (%)] | 93.19 | 95.96 | 94.24 | 0.228 | 0.432 | ||||
| Seroconversion [n (%)] | 67.54 | 69.19 | 56.54 | 0.726 | 0.010 | -1.65(-10.9,7.59) | -12.65(-22.18,-3.12) | No | No |
| GMT | 141.90 | 148.10 | 118.00 | 0.697 | 0.040 | 0.96(0.77,1.19) | 0.8(0.64,0.99) | Yes | Yes |
| B/Yamagata | |||||||||
| Seropositivity-BI [n (%)] | 56.02 | 54.04 | 59.69 | 0.695 | 0.261 | ||||
| GMT-BI | 37.47 | 36.01 | 40.58 | 0.624 | 0.148 | ||||
| Seropositivity [n (%)] | 97.38 | 96.46 | 96.86 | 0.601 | 0.829 | ||||
| Seroconversion [n (%)] | 68.59 | 67.68 | 61.78 | 0.847 | 0.224 | 0.91(-8.35,10.17) | -5.9(-15.38,3.59) | Yes | No |
| GMT | 196.10 | 177.70 | 149.90 | 0.364 | 0.905 | 1.1(0.89,1.36) | 0.84(0.7,1.02) | Yes | Yes |
*Non-inferiority for the GMT ratio is considered to be fulfilled when the lower boundary of 95% CI is 0.5 or higher. Non-inferiority for the seroconversion rate would be considered as achieved if the lower bound of the two-sided 95% CI of the difference was > -10%. BI, before injection; GMT, geometric mean titre; Blood samples were collected at 28 days after each group received the influenza vaccine. Seropositivity criteria: The protective level of HI antibody titer against certain antigen is ≥ 1:40; seroconversion criteria: the HI antibody titer is<1:10 before vaccination and ≥1:40 after vaccination; the HI antibody titer is ≥ 1:10 before vaccination and increased by four times after vaccination.