Table 7.
Meta-regression analysis of factors associated with VE against severe COVID-19
| Factors | b | 95% CI | P | S.E | Exp(b) | 95% CI |
|---|---|---|---|---|---|---|
| Study regiona | ||||||
| Western Pacific region | Ref | – | – | – | 1 | – |
| Region of Americas | 0.463 | (0.035, 0.891) | 0.034 | 0.214 | 1.589 | (1.036, 2.438) |
| European region | 2.587 | (1.757, 3.418) | < 0.001 | 0.416 | 13.290 | (5.795, 30.508) |
| Region of South-East Asia | 0.077 | (− 0.663, 0.816) | 0.837 | 0.370 | 1.080 | (0.515, 2.261) |
| Eastern Mediterranean region | − 0.001 | (− 0.505, 0.502) | 0.996 | 0.252 | 0.999 | (0.604, 1.652) |
| VOC | ||||||
| Alpha | Ref | – | – | – | 1 | – |
| Gamma | 0.786 | (0.063, 1.510) | 0.034 | 0.362 | 2.195 | (1.065, 4.527) |
| Delta | 0.983 | (0.413, 1.553) | 0.001 | 0.286 | 2.672 | (1.511, 4.726) |
| Omicron | 1.138 | (0.479, 1.798) | 0.001 | 0.330 | 3.121 | (1.614, 6.038) |
| Others | 0.415 | (− 0.283, 1.112) | 0.240 | 0.350 | 1.514 | (0.754, 3.040) |
| Population type | ||||||
| General | Ref | – | – | – | 1 | – |
| HCWs | 0.757 | (− 0.717, 2.230) | 0.309 | 0.738 | 2.132 | (0.488, 9.300) |
| COVID-19 inpatient | 1.346 | (0.738, 1.955) | < 0.001 | 0.305 | 3.842 | (2.092, 7.064) |
| Chronical patient | 0.512 | (− 0.147, 1.171) | 0.126 | 0.330 | 1.669 | (0.863, 3.225) |
| Age range | ||||||
| 18–59 | Ref | – | – | – | 1 | – |
| < 18 | − 0.546 | (− 1.184, 0.093) | 0.093 | 0.320 | 0.579 | (0.306, 1.097) |
| ≥ 60 | 0.568 | (0.290, 0.847) | < 0.001 | 0.140 | 1.765 | (1.336, 2.333) |
| Othersb | 0.503 | (− 0.180, 1.186) | 0.146 | 0.342 | 1.654 | (0.835, 3.274) |
| Vaccine doses | ||||||
| Primary | Ref | – | – | – | 1 | – |
| Booster | − 0.614 | (− 0.972, − 0.257) | 0.001 | 0.179 | 0.541 | (0.378, 0.773) |
| Study design | ||||||
| Cohort studyc | Ref | – | – | – | 1 | – |
| Retrospective cohort study | 0.883 | (0.447, 1.319) | < 0.001 | 0.218 | 2.418 | (1.564, 3.740) |
| Case–control study | 0.103 | (− 0.290, 0.496) | 0.603 | 0.197 | 1.108 | (0.748, 1.642) |
| Descriptive study | − 1.863 | (− 2.685, − 1.040) | < 0.001 | 0.412 | 0.155 | (0.068, 0.353) |
| Constant | − 2.789 | (− 3.549, − 2.029) | < 0.001 | 0.381 | 0.061 | (0.029, 0.131) |
aCountries included in each region: Western Pacific Region includes China (Mainland and Hong Kong) and Malaysia; region of Americas includes Argentina, Brazil, Chile, Colombia, and Mexico; European region includes Hungary, Serbia, and Turkey; region of South-East Asia includes Thailand and Indonesia; Eastern Mediterranean region includes Egypt, Iran, Morocco, Pakistan, and United Arab Emirates
bMixed, aged 18 years and older and cross-age ranges or not extractable
cProspective cohort