Figure 3.

Serological profile follow‐up overtime. Workers whose serum was positive for IgG anti‐N (A–C), anti‐S (D–F), and pseudo‐neutralization activity (G–I) at the first blood sampling (t ₀) were reassessed together with serum obtained 6–12 weeks later (t₁ ). (A–G) Test values according to delay between date of symptom onset and the two serum analyses: t ₀ (blue dots) and t ₁ (red dots). Linear regression is plotted. Coefficient of determination and associated p value are indicated. (B–H) Whisker‐plots summarizing test value for both tests (t ₀ and t ₁). Statistical significance was determined using a Wilcoxon test (****p < 0.0001). (C–I) Individual follow‐up of seropositive workers with a decreasing value. Variation of mean (t ₀ /t ₁) is indicated in %.