Table 2.
Vaccine effectiveness for any primary COVID-19 vaccine series against infections, hospitalisations, and mortality I2
|
Baseline, days |
Follow-up, days |
I2 | σ | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 0–13 | 14–42 | 112–139 | 140–167 | 168–195 | 196–223 | 224–251 | 252–279 | 280–307 | ||||
| Any variant | ||||||||||||
| Documented infections | ||||||||||||
| Vaccine effectiveness | 67% (95% CI 53 to 77; 95% PI −20 to 91) | 83%* (95% CI 80 to 86; 95% PI 39 to 95) | 62%† (95% CI 53 to 69; 95% PI −29 to 89) | 56%† (95% CI 47 to 63; 95% PI −38 to 88) | 51%*† (95% CI 40 to 60; 95% PI −44 to 87) | 56%† (95% CI 43 to 66; 95% PI −38 to 88) | 50%*† (95% CI 34 to 61; 95% PI −46 to 86) | 49%† (95% CI 27 to 64; 95% PI −48 to 86) | 47%† (95% CI 18 to 65]; 95% PI −51 to 86) | 53, 47 | 0·48, 0·44 | |
| κ | 8 (14) | 40 (96) | 22 (50) | 31 (77) | 21 (49) | 15 (23) | 13 (21) | 8 (12) | 6 (8) | .. | .. | |
| Hospitalisations | ||||||||||||
| Vaccine effectiveness | 88% (95% CI 75 to 94; 95% PI 20 to 98) | 92% (95% CI 88 to 94; 95% PI 51 to 99) | 89%† (95% CI 84 to 92; 95% PI 33 to 98) | 86%† (95% CI 80 to 90; 95% PI 20 to 98) | 83%† (95% CI 74 to 89; 95% PI −2 to 97) | 82%† (95% CI 70 to 89; 95% PI −10 to 97) | 79%† (95% CI 65 to 87; 95% PI −23 to 97) | .. | .. | 33, 65 | 0.51, 0·72 | |
| κ | 4 (7) | 21 (55) | 11 (37) | 15 (37) | 9 (19) | 6 (8) | 7 (9) | .. | .. | .. | .. | |
| Mortality | ||||||||||||
| Vaccine effectiveness | .. | 91% (95% CI 85 to 95; 95% PI 45 to 99) | 91% (95% CI 81 to 95; 95% PI 37 to 99) | 85%† (95% CI 73 to 91; 95% PI 3 to 98) | 86% (95% CI 73 to 93; 95% PI 9 to 98) | .. | .. | .. | .. | 26, 69 | 0·46, 0·75 | |
| κ | .. | 10 (23) | 4 (7) | 8 (15) | 4 (8) | .. | .. | .. | .. | .. | .. | |
| Omicron | ||||||||||||
| Documented infections | ||||||||||||
| Vaccine effectiveness | .. | 61% (95% CI 51 to 68; 95% PI 11 to 83) | 36%† (95% CI 18 to 50; 95% PI −32 to 72) | 31%*† (95% CI 14 to 45; 95% PI −36 to 70) | 21%*† (95% CI 0 to 38; 95% PI −44 to 66) | 34%*† (95% CI 16 to 49; 95% PI −34 to 71) | .. | .. | 22%*† (95% CI −9 to 45; 95% PI −46 to 67) | 32, 68 | 0·22, 0·33 | |
| κ | .. | 12 (21) | 6 (10) | 7 (14) | 5 (10) | 6 (8) | .. | .. | 4 (4) | .. | .. | |
| Hospitalisations | ||||||||||||
| Vaccine effectiveness | .. | 71% (95% CI 58 to 80; 95% PI 32 to 88) | .. | .. | 52%† (95% CI 29 to 67; 95% PI −12 to 79) | .. | .. | .. | .. | 40, 55 | 0·23, 0·27 | |
| κ | .. | 6 (7) | .. | .. | 4 (4) | .. | .. | .. | .. | .. | .. | |
I2 is Higgin's and Thompson's I2 presented at the within-study and between-study levels. σ is an estimate of τ, the SD of effect sizes in the population, presented at the within-study and between-study levels. κ=number of studies pooled (number of cohorts or observations pooled). PI=prediction interval.
*
Vaccine effectiveness at this follow-up timepoint is statistically different from the vaccine effectiveness observed at baseline 1 (0–13 days).
†
Vaccine effectiveness at this follow-up timepoint is statistically different from the vaccine effectiveness observed at baseline 2 (14–42 days).