Table 1.
Detection of COVID-19 samples collected at different time points postsymptom onset by SARS-CoV-2 surrogate and conventional neutralization assays.
| Days postsymptom onset | sVNT | PRNT-50 | PRNT-90 |
|---|---|---|---|
| 1–7 (n = 39) |
56.4% (22; 39.6%–72.2%) |
66.7% (26; 49.8%–80.9%, P= 0.4795) |
30.8%a (12; 17.0%–47.6%, P= 0.0094) |
| 8–14 (n = 60) |
73.3% (44; 60.3%–83.9%) |
75.0% (45; 62.1%–85.3%, P = 1.000) |
50.0%b (30; 36.8%–63.2%, P = 0.0005) |
| 15–21 (n = 20) |
95.0% (19; 75.1%–99.9%) |
95.0% (19; 75.1%–99.9%, P = 1.000) |
65.0%a (13; 40.8%–84.6%, P = 0.0412) |
| 22–28 (n = 9) |
88.9% (8; 51.8%–99.7%) |
100% (9; 66.4%–100%, P = 0.4795) |
66.7% (6; 29.9%–92.5%, P = 0.4795) |
| 29–35 (n = 12) |
83.3% (10; 51.6%–97.9%) |
75.0% (9; 42.8%–94.5%, P = 1.000) |
66.7% (8; 34.9%–90.1%, P = 0.4795) |
| 36–42 (n = 13) |
84.6% (11; 54.6%–98.1%) |
84.6% (11; 54.6%–98.1%, P = 0.3428) |
46.2% (6; 19.2%–74.9%, P = 0.0736) |
| 43–49 (n = 20) |
100% (20; 83.2%–100%) |
100% (20; 83.2%–100%, P = 1.000) |
50.0%a (10; 25.2%–72.8%, P = 0.0044) |
| 50+ (n = 21) |
90.5% (19; 69.6%–98.8%) |
85.7% (18; 63.7%–97.0%, P = 1.000) |
61.9%a (13; 38.4%–81.9%, P = 0.0412) |
| Total (n = 194) |
78.9% (153; 72.4%–84.4%) |
80.9% (157; 74.7%–86.2%, P = 0.5708) |
50.5%c (98; 43.3%–57.8%, P< 0.0001) |
Number of specimens and 95% confidence intervals are indicated in parentheses. Two-tailed McNemar tests were conducted to analyze the increase in detection of COVID-19+ samples conferred by sVNT compared with PRNT-50 or PRNT-90. sVNT vs. PRNT-50 *P < 0.05, **P < 0.001, ***P < 0.0001. sVNT vs PRNT-90.
a
P < 0.05,
b
P < 0.001,
c
P < 0.0001.