Table 2.
Summary of immunogenicity between heterologous and homologous prime-boost schedules at 28 days post boost
|
Prime with ChAd |
Prime with BNT |
||||||
|---|---|---|---|---|---|---|---|
| ChAd/ChAd | ChAd/m1273 | ChAd/NVX | BNT/BNT | BNT/m1273 | BNT/NVX | ||
| Per-protocol analysis | |||||||
| SARS-CoV-2 anti-spike IgG, ELU/mL | |||||||
| n/N | 163/164 | 162/162 | 158/160 | 159/163 | 153/154 | 163/166 | |
| GMC | 1971 (1718 to 2262) | 20 114 (18 160 to 22 279) | 5597 (4756 to 6586) | 16 929 (15 025 to 19 075) | 22 978 (20 597 to 25 636 | 8874 (7391 to 10 654) | |
| GMR* | Ref | 10·2 (8·4 to ∞) | 2·8 (2·2 to ∞) | Ref | 1·3 (1·1 to ∞) | 0·5 (0·4 to ∞) | |
| Modified intention-to-treat analysis | |||||||
| SARS-CoV-2 anti-spike IgG, ELU/mL | |||||||
| n/N | 170/171 | 167/167 | 165/167 | 163/167 | 163/164 | 169/172 | |
| GMC | 1959 (1704 to 2253) | 20 360 (18 411 to 22 517) | 5440 (4632 to 6390) | 16 838 (14 985 to 18 921) | 23 187 (20 891 to 25 735) | 8913 (7464 to 10 644) | |
| GMR* | Ref | 10·5 (8·9 to 12·3) | 2·8 (2·2 to 3·4) | Ref | 1·3 (1·2 to 1·6) | 0·53 (0·43 to 0·65) | |
| Live virus neutralising antibody (Victoria†), FRNT50 | |||||||
| n/N | 47/171 | 48/167 | 51/167 | 46/167 | 48/164 | 49/172 | |
| GMC | 109 (70 to 168) | 1684 (1313 to 2162) | 432 (301 to 618) | 1501 (1188 to 1896) | 1883 (1546 to 2294) | 1109 (805 to 1529) | |
| GMR* | Ref | 16·9 (10·1 to 28·0) | 4·2 (2·4 to 7·2) | Ref | 1·3 (1·0 to 1·8) | 0·8 (0·6 to 1·2) | |
| Live virus neutralising antibody (Victoria†), normalised NT80 | |||||||
| n/N | 19/171 | 18/167 | 20/167 | 17/167 | 19/164 | 21/172 | |
| GMC | 331 (213 to 514) | 2244 (1737 to 2901) | 630 (398 to 997) | 3216 (2336 to 4427) | 3252 (2416 to 4376) | 868 (494 to 1527) | |
| GMR* | Ref | 7·5 (4·4 to 12·7) | 2·0 (1·0 to 3·9) | Ref | 1·0 (0·6 to 1·6) | 0·3 (0·1 to 0·6) | |
| Pseudotype virus neutralising antibody, NT50 | |||||||
| n/N | 169/171 | 154/167 | 158/167 | 159/167 | 157/164 | 163/172 | |
| GMC | 132 (113 to 154) | 1358 (1182 to 1562) | 473 (399 to 561) | 883 (751 to 1039) | 1260 (1106 to 1436) | 787 (631 to 981) | |
| GMR* | Ref | 10·0 (8·1 to 12·3) | 3·4 (2·7 to 4·3) | Ref | 1·4 (1·2 to 1·7) | 0·9 (0·7 to 1·2) | |
| Cellular response (wild-type), SFC per million PBMCs‡ | |||||||
| n/N | 95/171 | 101/167 | 98/167 | 96/167 | 98/164 | 102/172 | |
| GMC | 45 (34 to 61) | 148 (118 to 187) | 190 (159 to 227) | 49 (39 to 63) | 76 (58 to 99) | 29 (22 to 38) | |
| GMR* | Ref | 3·5 (2·5 to 4·8) | 4·8 (3·6 to 6·6) | Ref | 1·5 (1·1 to 2·2) | 0·6 (0·4 to 0·9) | |
In the per-protocol analysis, data are n/N, GMC (95% CI), and GMR (98·75% CI); in the modified intention-to-treat analysis, data are n/N, GMC (95% CI), and GMR (95% CI). BNT=BNT162b2 vaccine, Pfizer–BioNTech. ChAd=ChAdOx1 nCoV-19 vaccine, AstraZeneca. ELU=ELISA laboratory units. FRNT50=50% focus reduction neutralising antibody titre. GMC=geometric mean concentration. GMR=geometric mean ratio. m1273=mRNA–1273 vaccine, Moderna. NT80=80% neutralising antibody titre. NVX=NVXCoV2373 vaccine, Novavax. NT50=50% neutralising antibody titre. SFC=spot-forming cells. PBMC=peripheral blood mononuclear cell.
GMRs were adjusted for randomisation stratification variables, including study site and cohort, with one-sided 98·75% CIs in per-protocol analyses and were further adjusted for interval between first and second dose and baseline immunogenicity, with two-sided 95% CIs in the modified intention-to-treat analyses; non-inferiority margin is 0·63.
A Wuhan-related strain isolated early in the pandemic from Australia.
Cellular response data were available in around 60% of sites, the rest of the study sites did not collect plasma samples due to logistical challenges.