Table 2. Seroconversion and seroprotection rate.
| SEROCONVERSION | SEROPROTECTION | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| T1 | T3 | T6 | T0 | T1 | T3 | T6 | ||||||||
| % | (n/n total) | % | (n/n total) | % | (n/n total) | % | (n/n total) | % | (n/n total) | % | (n/n total) | % | (n/n total) | |
| HUa | 22 | (10/45) | 11 | (5/45) | 3 | (1/38) | 92 | (44/48) | 92 | (44/48) | 100 | (45/45) | 97 | (36/37) |
| CTb | 33 | (3/9) | 33 | (3/9) | 25 | (2/8) | 100 | (9/9) | 100 | (9/9) | 100 | (9/9) | 100 | (8/8) |
| CT+HU | 17 | (1/6) | 17 | (1/6) | 0 | (0/6) | 100 | (7/7) | 100 | (7/7) | 100 | (7/7) | 100 | (7/7) |
| No DMTc | 14 | (1/7) | 33 | (2/6) | 0 | (0/2) | 86 | (6/7) | 100 | (8/8) | 100 | (6/6) | 100 | (2/2) |
| SCD | 22 | (15/67)* | 17 | (11/66)* | 6 | (3/54)* | 93 | (66/71) | 94 | (68/72) | 100 | (67/67) | 98 | (53/54) |
| SCD>16y | 30 | (11/36)** | 29 | (8/28)** | 12 | (3/26)** | 92 | (34/37) | 97 | (37/38) | 100 | (37/37) | 97 | (28/29) |
| CTRL | 68 | (19/28) | 43 | (13/30) | 26 | (7/27) | 47 | (14/30) | 96 | (27/28) | 93 | (28/30) | 78 | (21/27) |
| P-value | 0.0051* | 0.0667* | 0.1710* | |||||||||||
| P-value | <0.0001** | 0.0098** | 0.0136** | |||||||||||
A 4-fold increase in HAI titers between two paired samples is considered as positive for seroconversion. Seroconversion at T1, T3, T6 was defined relative to the titer at T0. Fisher exact test was used to compare the seroconversion rate between controls and SCD patients. HAI titers of 1:40 or more are considered positive for seroprotection.
*SCD vs CTRL
**SCD>16y vs CTRL
a Hydroxyurea (HU)
b Chronic transfusion (CT)
c No Disease modifying therapy (DMT)