Table 2.
Antibody responses to SARS-CoV-2 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&3 | Group 2&3 | Group 1&3 | Group 2&3 | Group 1&3 | Group 2&3 | |
| Seropositivity-BI [n (%)] | 35.29 | 36.54 | 34.63 | 0.918 | 0.758 | ||||
| GMT-BI | 5.39 | 5.72 | 5.51 | 0.505 | 0.999 | ||||
| Seropositivity [n (%)] | 98.04 | 100.00 | 98.54 | 0.724 | 0.121 | ||||
| Seroconversion [n (%)] | 93.14 | 95.67 | 94.63 | 0.544 | 0.654 | -1.49(-6.13,3.15) | 1.04(-3.1,5.18) | Yes | Yes |
| GMT | 114.70 | 120.30 | 161.80 | 0.012 | 0.033 | 0.71(0.57,0.88) | 0.74(0.6,0.92) | Yes | Yes |
| Aged 18-59 | |||||||||
| GMT | 106.4 | 112.9 | 171.2 | <0.01 | 0.01 | 0.62(0.51,0.83) | 0.66(0.50,0.88) | Yes | Yes |
| Seroconversion [n (%)] | 92.86 | 95.37 | 92.73 | 1.000 | 0.524 | 0.13(-6.67,6.93) | 2.64(-3.63,8.91) | Yes | Yes |
| Aged ≥60 | |||||||||
| GMT | 125.70 | 128.90 | 151.50 | 0.182 | 0.189 | 0.83(0.59,1.16) | 0.85(0.62,1.17) | Yes | Yes |
| Seroconversion [n (%)] | 93.48 | 96.84 | 95.47 | 0.325 | 1.000 | -3.36(-9.51,2.79) | -0.84(-6.05,4.37) | 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 inactivated SARS-CoV-2 vaccine. For antibody responses to SARS-CoV-2, seropositivity criteria: The neutralizing antibody titer is ≥1:8; seroconversion criteria: the neutralizing antibody titer is < 1:8 before immunization and ≥ 1:8 after immunization; or the neutralizing antibody titer is ≥ 1:8 before immunization and increases by 4 times and above after immunization.