Table 2.
Prior vaccination and documented SARS-CoV-2 infection among individuals infected with SARS-CoV-2 according to infecting lineage
| Exposure | Cases, n/N (%) | Odds ratio (95% CI), JN.1 vs. non-JN.1 infection | ||
|---|---|---|---|---|
| S-gene detected (non-BA.2.86 lineage) | S-gene target failure (BA.2.86-derived lineage) | Unadjusteda | Adjustedb | |
| N = 4614 | N = 3080 | |||
| Receipt of updated COVID-19 vaccinesc | ||||
| No XBB.1.5 (monovalent) vaccine doses | 4041 (87.6) | 2579 (83.7) | ref. | ref. |
| Any XBB.1.5 (monovalent) vaccine doses | 573 (12.4) | 501 (16.3) | 1.23 (1.11, 1.35) | 1.14 (1.01, 1.28) |
| No BA.4/BA.5 (bivalent) vaccine doses | 3205 (69.5) | 1996 (64.8) | ref. | ref. |
| Any BA.4/BA.5 (bivalent) vaccine doses | 1409 (30.5) | 1084 (35.2) | 1.14 (1.06, 1.23) | 1.10 (1.01, 1.20) |
| 0 Omicron-targeted vaccine doses | 3096 (67.1) | 1927 (62.6) | ref. | ref. |
| Any Omicron-targeted vaccine | 1518 (32.9) | 1153 (37.4) | 1.13 (1.05, 1.22) | 1.12 (1.03, 1.21) |
| Both BA.4/BA.5 (bivalent) and XBB1.5 (monovalent) vaccines | 464 (10.1) | 432 (14.0) | 1.43 (1.15, 1.43) | 1.28 (1.13, 1.45) |
| Number of vaccine doses received | ||||
| 0 vaccine doses | 569 (12.3) | 272 (8.8) | ref. | ref. |
| 1 vaccine dose | 122 (2.6) | 66 (2.1) | 1.08 (0.83, 1.41) | 1.05 (0.80, 1.38) |
| 2 vaccine doses | 901 (19.5) | 564 (18.3) | 1.16 (1.01, 1.34) | 1.10 (0.94, 1.28) |
| 3 vaccine doses | 1453 (31.5) | 1011 (32.8) | 1.27 (1.11, 1.45) | 1.20 (1.04, 1.39) |
| 4 vaccine doses | 824 (17.9) | 570 (18.5) | 1.25 (1.08, 1.44) | 1.23 (1.05, 1.44) |
| 5 vaccine doses | 415 (9.0) | 331 (10.7) | 1.34 (1.14, 1.58) | 1.43 (1.20, 1.71) |
| 6 vaccine doses | 285 (6.2) | 231 (7.5) | 1.32 (1.11, 1.58) | 1.57 (1.28, 1.91) |
| ≥7 vaccine doses | 45 (1.0) | 35 (1.1) | 1.32 (0.93, 1.88) | 1.69 (1.16, 2.45) |
| Timing of prior vaccinationc | ||||
| No doses received | 569 (12.3) | 272 (8.8) | ref. | ref. |
| Last vaccine dose within <3 months | 527 (11.4) | 436 (14.2) | 1.18 (1.07, 1.31) | 1.05 (0.80, 1.38) |
| Last vaccine dose within 3–6 months | 79 (1.7) | 92 (3.0) | 1.35 (1.10, 1.66) | 1.09 (0.79, 1.52) |
| Last vaccine dose >6 months prior | 3439 (74.5) | 2280 (74.0) | 0.98 (0.90, 1.06) | 0.97 (0.81, 1.17) |
| Documented prior infection | ||||
| 0 documented infections | 2505 (54.3) | 1506 (48.9) | ref. | ref. |
| Any prior infection | 2109 (45.7) | 1574 (51.1) | 1.14 (1.06, 1.22) | 1.09 (1.02, 1.18) |
| 1 documented infection | 1753 (38.0) | 1269 (41.2) | 1.11 (1.03, 1.20) | 1.08 (1.00, 1.17) |
| 2 documented infections | 332 (7.2) | 278 (9.0) | 1.17 (1.03, 1.33) | 1.14 (0.99, 1.30) |
| ≥3 documented infections | 24 (0.5) | 27 (0.9) | 1.37 (0.93, 2.00) | 1.30 (0.89, 1.91) |
Data encompass the primary analytic cohort (N = 7694 individuals), comprised of individuals testing positive for SARS-CoV-2 from tests undertaken in outpatient settings between 1 December, 2023 and 30 January, 2024 which were processed via TaqPath COVID-19 Combo Kit assays, who belonged to KPSC health plans for at least 1 year prior to their index test date.
aUnadjusted odds ratios are computed via conditional logistic regression models matching on week of testing alone.
bAdjusted odds ratios are computed via conditional logistic regression models matching on week of testing and controlling for age, sex, race/ethnicity, body mass index, history of cigarette smoking, prior-year healthcare utilization across all settings, Charlson comorbidity index, and median household income within cases’ census tract according to the categorization scheme indicated in Table 1. Missing values were addressed via multiple imputation, with results pooled across five pseudo-dataset replicates.
cAnalyses of vaccine type and timing adjust for a number of monovalent wild-type (Wuhan-Hu-1) vaccine doses received.