Table 1.
Follow up of anti-S1-S2 IgG antibody titers according to SARS-CoV-2 infection history.
| Time Points | Total (n = 112) (AU/mL) |
Median-Fold Increase 1 (n = 112) | Negative SARS-CoV-2 Infection (AU/mL) Before Vaccination (n = 63) |
Median-Fold Increase Negative SARS-CoV-2 Infection |
Positive SARS-CoV-2 Infection (AU/mL) Before Vaccination (n = 49) |
Median-Fold Increase Positive SARS-CoV-2 Infection |
p-Value |
|---|---|---|---|---|---|---|---|
| 21–28 days after first dose (T1) | 122 (1837.8) | 97.6 (68.6) n = 63 |
2220 (6005) n = 49 |
<0.001 | |||
| 21–28 days after second dose (T2) | 1875 (2065) | 10.66 | 1495 (1430) n = 62 |
14.1 | 2680 (3920) n = 50 |
1.52 | <0.001 |
| Three months after second dose (T3) | 300 (540.2) | 1.98 | 217 (236) n = 62 |
2.58 | 452 (1355) n = 50 |
0.36 | <0.001 |
| 1–7 days after third dose (T4) | 489 (1019.2) | 2.22 | 416 (988) n = 60 |
3.85 | 740 (1245) n = 52 |
0.46 | 0.040 |
| 21–28 days after third dose (T5) | 3020 (2210) | 21.03 | 2805 (1765) n = 60 |
32.2 | 3256 (2403) n = 52 |
1.72 | 0.094 |
| Three months after third dose (T6) | 1035 (914.6) | 6.06 | 853 (813) n = 60 |
8.5 | 1285 (1052) n = 52 |
0.62 | 0.002 |
| Prior to the application of fourth dose (T7) | 598 (707.5) | 2.98 | 448 (492) n = 60 |
4.85 | 693 (1270) n = 52 |
0.55 | 0.006 |
| 21–28 days after fourth dose (T8) | 4230 (3337.5) | 30.81 | 4080 (3638) n = 54 |
40 | 4455 (3302) n = 58 |
2.4 | 0.512 |
| p-value | <0.001 | <0.001 | <0.001 | <0.001 |
SARS-CoV-2 infection is presented as cumulative case count. Some subjects could have had SARS-CoV-2 more than once. Data are presented as medians and interquartile ranges. The Friedman test was performed for comparison between time points. The Mann–Whitney U test was applied for comparisons between individuals with a positive and negative SARS-CoV-2 infection. A p < 0.05 was considered statistically significant. 1 The increase throughout follow up was compared with the antibody titers determined 21–28 days after the first dose.