Table 4 Adjusted relative vaccine effectiveness of the booster vaccination comparing to full vaccination of inactivated Covid-19 vaccine
|  | Fully vaccinated group (N = 2,084,721) |  | Booster vaccinated group (N = 2,084,721) | Risk difference per million PWs (95% CI) | rVE (95% CI) | |
|---|---|---|---|---|---|---|
| Â | Events | Risk per million PWs | Events | Risk per million PWs | Â | Â |
Outcome 1: Documented SARS-CoV-2 infection | ||||||
Overall | 23,193 | 774.9 | 19,470 | 648.7 | 126.2 (125.4, 127.1) | 16.3 (14.4, 17.9) |
Age group—no. | ||||||
    60–69 years old | 16,483 | 793.7 | 14,027 | 673.6 | 120.1 (119.1, 121.1) | 15.1 (13.2, 17.0) |
    70–79 years old | 6106 | 744.7 | 4875 | 592.6 | 152.1 (150.0, 154.1) | 20.4 (17.4, 23.4) |
    80–89 years old | 578 | 619.6 | 544 | 582.0 | 37.6 (36, 39.2) | 6.1 (−5.5, 16.5) |
    90 years old and above | 26 | 830.9 | 24 | 765.4 | 65.5 (52.4, 78.6) | 6.7 (−62.5, 46.4) |
Sex—no. | ||||||
    Male | 11,689 | 789.9 | 9442 | 636.0 | 153.9 (152.4, 155.4) | 19.5 (17.3, 21.7) |
    Female | 11,504 | 760.2 | 10,028 | 661.0 | 99.2 (98.2, 100.1) | 13.0 (10.7, 15.3) |
Whether having chronic disease | ||||||
    0 | 14,728 | 787.3 | 12,882 | 686.9 | 100.4 (99.5, 101.3) | 12.7 (10.6, 14.8) |
    ≥1 | 8465 | 754.3 | 6588 | 585.0 | 169.3 (167.3, 171.2) | 22.5 (20.0, 25.0) |
Time interval between 1st dose and 2nd dose | ||||||
    21–56 days | 23,048 | 774.8 | 19,333 | 648.0 | 126.7 (125.9, 127.6) | 16.4 (14.8, 18.0) |
    57–180 days | 145 | 800.3 | 137 | 754.3 | 46.0 (42.0, 49.9) | 5.9 (−18.8, 25.5) |
    181 days and above | 0 | 0 | 0 | 0 | – | – |
Time interval since completion of 2nd dose (days) | ||||||
    181–270 | 21,549 | 795.1 | 18,172 | 668.6 | 126.6 (125.7, 127.5) | 15.9 (14.2, 17.6) |
    271–360 | 1630 | 718.2 | 1298 | 570.2 | 147.9 (144.1, 151.8) | 20.5 (14.5, 26.1) |
    361 and above | 14 | 25.0 | 0 | 0 | 25.0 (13.7, 35.4) | 100 (NA) |
Outcome 2: Severe/critical Covid-19 | ||||||
Overall | 66 | 2.2 | 26 | 0.9 | 1.3 (1.1, 1.5) | 60.5 (37.8, 74.9) |
Age group—no. | ||||||
    60–69 years old | 16 | 0.8 | 9 | 0.4 | 0.3 (0.2, 0.4) | 44.4 (−25.8, 75.4) |
    70–79 years old | 26 | 3.2 | 8 | 1.0 | 2.2 (1.7, 2.7) | 69.1 (31.9, 86.0) |
    80–89 years old | 24 | 25.7 | 6 | 6.4 | 19.3 (14.1, 24.3) | 74.9 (38.7, 89.8) |
    90 years old and above | 0 | 0 | 3 | 95.7 | Nonea | Nonea |
Sex—no. | ||||||
    Male | 15 | 1 | 5 | 0.3 | 0.7 (0.5, 0.9) | 66.6 (8.1, 87.9) |
    Female | 51 | 3.4 | 21 | 1.4 | 2.0 (1.7, 2.3) | 58.7 (31.3, 75.1) |
Whether having chronic disease | ||||||
    0 | 29 | 1.6 | 12 | 0.6 | 0.9 (0.7, 1.1) | 58.7 (19.1, 78.9) |
    ≥1 | 37 | 3.3 | 14 | 1.2 | 2.1 (1.6, 2.5) | 61.9 (29.6, 79.4) |
Time interval between 1st dose and 2nd dose | ||||||
    21–56 days | 64 | 2.2 | 26 | 0.9 | 1.3 (1.1, 1.5) | 59.3 (35.7, 74.2) |
    57–180 days | 2 | 11 | 0 | 0 | 11.0 (1.3, 19.6) | 100 (NA) |
    181 days and above | 0 | 0 | 0 | 0 | – | – |
Time interval since completion of 2nd dose (days) | ||||||
    181–270 | 63 | 2.3 | 26 | 1 | 1.4 (1.2, 1.6) | 58.7 (34.7, 73.8) |
    271–360 | 3 | 1.3 | 0 | 0 | 1.3 (0.3, 2.2) | 100 (NA) |
    361 and above | 0 | 0 | 0 | 0 | – | – |
Outcome 3: Covid-19-related death | ||||||
Overall | 11 | 0.4 | 2 | 0.1 | 0.3 (0.2, 0.4) | 81.7 (17.5, 95.9) |
Age group—no. | ||||||
    60–69 years old | 3 | 0.1 | 0 | 0 | 0.1 (0, 0.2) | 100 (NA) |
    70–79 years old | 2 | 0.2 | 1 | 0.1 | 0.1 (0, 0.2) | 50.7 (−443.5, 95.5) |
    80–89 years old | 6 | 6.4 | 0 | 0 | 6.4 (2.4, 10.1) | 100 (NA) |
    90 years old and above | 0 | 0 | 1 | 31.9 | Nonea | Nonea |
Sex—no. | ||||||
    Male | 5 | 0.3 | 1 | 0.1 | 0.3 (0.1, 0.4) | 80.2 (−69.3, 97.7) |
    Female | 6 | 0.4 | 1 | 0.1 | 0.3 (0.1, 0.5) | 82.9 (−42.4, 97.9) |
Whether having chronic disease | ||||||
    0 | 7 | 0.4 | 1 | 0.1 | 0.3 (0.1, 0.5) | 85.7 (−15.9, 98.2) |
    ≥1 | 4 | 0.4 | 1 | 0.1 | 0.3 (0.1, 0.4) | 74.6 (−127.5, 97.2) |
Time interval between 1st dose and 2nd dose | ||||||
    21–56 days | 11 | 0.4 | 2 | 0.1 | 0.3 (0.2, 0.4) | 81.7 (17.5, 95.9) |
    57–180 days | 0 | 0 | 0 | 0 | – | – |
    181 days and above | 0 | 0 | 0 | 0 | – | – |
Time interval since completion of 2nd dose (days) | ||||||
    181–270 | 11 | 0.4 | 2 | 0.1 | 0.3 (0.2, 0.5) | 81.8 (17.7, 96.0) |
    271–360 | 0 | 0 | 0 | 0 | – | – |
    361 and above | 0 | 0 | 0 | 0 | – | – |
