Table 8.
The relative effectiveness of booster immunization of COVID-19 vaccines to prevent SARS-CoV-2 infection and COVID-19 caused by the Omicron variant.
| Type of disease | Type of vaccine | No. of studies | RR/OR (95% CI) | P h/I 2 (%)& | VE (%) (95% CI)# | P | Vaccine name |
|---|---|---|---|---|---|---|---|
| One dose of COVID-19 vaccine booster immunization* | |||||||
| Omicron variant (B.1.1.529) | |||||||
| Cohort studies: SARS-CoV-2 infection | Overall | 5 | 0.386 (0.289, 0.514) | <0.001/86.1 | 61.4 (48.6, 71.1) | <0.001 | |
| RNA-based vaccine | 4 | 0.372 (0.258, 0.538) | <0.001/89.5 | 62.8 (46.2, 74.2) | <0.001 | BNT162b2; mRNA-1273 | |
| Case–control studies: symptomatic COVID-19 | Overall | 3 | 0.326 (0.309, 0.344) | 0.205/37.0 | 67.4 (65.6, 69.1) | <0.001 | BNT162b2; mRNA-1273 |
| Omicron variant (BA.2) | |||||||
| Cohort studies: symptomatic COVID-19 | Overall | 2 | 0.422 (0.244, 0.731) | 0.111/60.6 | 57.8 (26.9, 75.6) | 0.002 | BNT16b2 |
| Severe COVID-19 | Overall | 2 | 0.122 (0.087, 0.173) | 0.650/0.0 | 87.8 (82.7, 91.3) | <0.001 | BNT16b2 |
| COVID-19-related death | Overall | 1 | 0.110 (0.060, 0.186) | NA | 89.0 (81.4, 94.0) | <0.001 | BNT16b2 |
| Two doses of COVID-19 vaccine booster immunization to prevent the Omicron variant (B.1.1.529) infection & | |||||||
| Non-randomized clinical studies: SARS-CoV-2 infection | Overall | 2 | 0.784 (0.568, 1.081) | 0.465/0.0 | 21.6 (-8.1, 43.2) | 0.138 | BNT162b2; mRNA-1273 |
| Symptomatic COVID-19 | Overall | 2 | 0.621 (0.432, 0.893) | 0.607/0.0 | 37.9 (10.7, 56.8) | 0.010 | BNT162b2; mRNA-1273 |
| Cohort studies: SARS-CoV-2 infection | Overall | 3 | 0.508 (0.482, 0.537) | 0.148/47.6 | 49.2 (46.3, 51.8) | <0.001 | |
| RNA-based vaccine | 2 | 0.521 (0.468, 0.582) | 0.058/72.1 | 47.9 (41.8, 53.2) | <0.001 | BNT16b2 | |
| Severe COVID-19 | Overall | 2 | 0.182 (0.073, 0.459) | 0.244/26.3 | 81.8 (54.1, 92.7) | <0.001 | |
| COVID-19-related death | Overall | 1 | 0.070 (0.010, 0.460) | NA | 93.0 (54.0, 99.0) | <0.001 | |
*Comparison between booster vaccinees and non-booster vaccinees groups; #Vaccine effectiveness = 100*(1–RR) % or 100*(1–OR) %& Comparison between two doses of COVID-19 vaccine booster immunization and one dose of COVID-19 vaccine booster immunization groups, VE, vaccine effectiveness.