Table 4.
Patient characteristics and incidence of ITP exacerbation following SARS-CoV-2 vaccination
| First vaccine dose | Second vaccine dose | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| n | Platelet count decrease ≥50%, n (%) | Platelet count decrease >20% and nadir <30 × 109/L, n (%) | Use of recue therapy, n (%) | ITP exacerbation,* n (%) | n | Platelet count decrease ≥50%, n (%) | Platelet count decrease >20% and nadir <30 × 109/L, n (%) | Use of rescue therapy, n (%) | ITP exacerbation,* n (%) | |
| All patients | 111 | 16 (14.4) | 10 (9) | 7 (6.3) | 19 (17.1) | 70 | 14 (20) | 10 (14.3) | 9 (12.9) | 14 (20) |
| Splenectomy | 25 | 11 (44) | 8 (32) | 6 (24) | 12 (48) | 19 | 7 (36.8) | 4 (21) | 4 (21) | 7 (36.8) |
| No splenectomy | 86 | 5 (5.8) | 2 (2.3) | 1 (1.2) | 7 (8.1) | 51 | 7 (13.7) | 6 (11.8) | 5 (9.8) | 7 (13.7) |
| Relative Risk [95% CI] |
1.8 [1.3-2.8] |
1.4 [1.02-2.2] |
||||||||
| 0-4 prior medical therapies | 54 | 2 (3.7) | 2 (3.7) | 3 (5.6) | 3 (5.6) | 43 | 7 (16.3) | 6 (14) | 6 (14) | 7 (16.3) |
| ≥5 prior medical therapies | 16 | 8 (50) | 4 (25) | 3 (18.8) | 9 (56.3) | 12 | 5 (41.7) | 2 (16.7) | 1 (8.3) | 5 (41.7) |
| Relative Risk [95% CI] |
2.2 [1.4-4.1] |
1.4 [0.9-2.6] |
||||||||
| Prior rituximab use† | 39 | 9 (23.1) | 4 (10.3) | 3 (7.7) | 10 (25.6) | 26 | 9 (34.6) | 5 (19.2) | 5 (19.2) | 9 (34.6) |
| No prior rituximab use† | 56 | 4 (7.1) | 4 (7.1) | 4 (7.1) | 6 (10.7) | 34 | 5 (14.7) | 5 (14.7) | 4 (11.8) | 5(14.7) |
| Relative Risk [95% CI] |
1.2 [0.9-1.6] |
1.3 [0.9-1.9] |
||||||||
| On current therapy for ITP | 67 | 11 (16.4) | 6 (9) | 4 (6) | 14 (20.9) | 40 | 11 (27.5) | 7 (17.5) | 6 (15) | 11 (27.5) |
| No current therapy, prevaccine platelet count <150 × 109/L | 30 | 4 (13.3) | 3(10) | 2 (6.7) | 4 (13.3) | 16 | 0 | 0 | 0 | 0 |
| No current therapy, prevaccine platelet count ≥150 × 109/L | 14 | 1 (7.1) | 1 (7.1) | 1 (7.1) | 1 (7.1) | 7 | 1 (12.5) | 1 (12.5) | 1 (12.5) | 1 (12.5) |
| Any concurrent autoimmune disease | 34 | 5 (14.7) | 3 (8.8) | 3 (8.8) | 6 (17.6) | 25 | 5 (20) | 4 (10) | 3 (12) | 5 (20) |
| No concurrent autoimmune disease | 47 | 4 (8.5) | 3 (6.4) | 2 (4.3) | 6 (12.8) | 30 | 6 (20) | 3 (16) | 3 (10) | 6 (20) |
| Relative Risk [95% CI] |
1.06 [0.8-1.4] |
1 [0.7-1.4] |
||||||||
*
Defined as development of any 1 or more of the following: (1) ≥50% decline in platelet count from prevaccination baseline; (2) >20% decline from prevaccination baseline and platelet nadir <30 ×109/L; and/or (3) receipt of rescue therapy for ITP.
†
Prior rituximab use was specifically solicited in data collection as well as all prior treatment history.