TABLE 2. Effectiveness of updated 2023–2024 (monovalent XBB.1.5) COVID-19 vaccination against laboratory-confirmed COVID-19–associated emergency department or urgent care encounters, by age group — VISION network, September 2023–January 2024.
| Age group, yrs/COVID-19 vaccination dosage pattern | No.
(column %) |
Median interval since last dose for vaccinated persons, days (IQR) | VE %* (95% CI) | |
|---|---|---|---|---|
| COVID-19 case-patients | COVID-19 control patients | |||
|
≥18
| ||||
| No updated
dose† (Ref) |
15,932 (92) |
98,218 (88) |
669 (403–792) |
Ref |
| Received updated
dose |
1,297 (8) |
13,378 (12) |
44 (26–64) |
47 (44–50) |
| 7–59 days earlier |
825 (5) |
9,372 (8) |
33 (20–46) |
51 (47–54) |
| 60–119 days earlier |
472 (3) |
4,006 (4) |
74 (66–83) |
39 (33–45) |
|
18–64
| ||||
| No updated
dose† (Ref) |
10,582 (97) |
69,423 (94) |
697 (480–832) |
Ref |
| Received updated
dose |
377 (3) |
4,739 (6) |
42 (24–62) |
50 (44–55) |
| 7–59 days earlier |
259 (2) |
3,457 (5) |
31 (19–45) |
52 (45–58) |
| 60–119 days earlier |
118 (1) |
1,282 (2) |
73 (66–83) |
45 (34–55) |
|
≥65
| ||||
| No updated
dose† (Ref) |
5,350 (85) |
28,795 (77) |
509 (362–733) |
Ref |
| Received updated
dose |
920 (15) |
8,639 (23) |
46 (27–66) |
45 (41–49) |
| 7–59 days earlier |
566 (9) |
5,915 (16) |
33 (21–46) |
49 (44–54) |
| 60–119 days earlier | 354 (6) | 2,724 (7) | 74 (66–83) | 37 (29–44) |
Abbreviations: Ref = referent group; VE = vaccine effectiveness; VISION = Virtual SARS-CoV-2, Influenza, and Other respiratory viruses Network.
* VE was calculated as (1 − odds ratio) × 100% with odds ratios calculated using multivariable logistic regression. For VISION, the odds ratio was adjusted for age, sex, race and ethnicity, geographic region, and calendar time (days since January 1, 2021).
† The “no updated dose” group included all eligible persons who did not receive an updated 2023–2024 COVID-19 vaccine dose, regardless of number of previous (i.e., original monovalent and bivalent) doses (if any) received.