Fig. 1.

Neutralising titres against SARS-CoV-2 of baseline and 6 months post-symptom onset convalescent samples from 48 subjects with mild COVID-19. A) 50% inhibitory dilution neutralising titres (ID₅₀) against infectious cell-culture derived SARS-CoV-2 between baseline and 6-month time points, with decreased neutralising titres (red, n=21), unchanged neutralising titres (grey, n=24) and increased neutralising titres (blue, n=3) as defined in B. Each dotted line on the X-axis represents the time post-symptom onset according to group stratification, with the first section (14-30 days) comprising subjects with the baseline sample obtained ≤1M post-symptom onset, the second section (31-60 days) 1-2M, the third section (61-90 days) 2-3M and the last section (91-160 days) >3M post-symptom onset. B) The changes in neutralising titres (∆ID₅₀) for all subjects from baseline to 6-months. Boosted titres (>100 ID₅₀ increase) are shown in the blue shading, unchanged titres (∆ID₅₀ between 100 and -100) are shown in the grey shading and decreased titres (>100 ID₅₀ decrease) are shown in the red shading. The line in the grey shading represents the median change for all values. C) Comparisons of ID₅₀ between baseline (BL; blue) and 6-month (6M; red) timepoints in all subjects (*p=0•045; Paired-parametric T test) and in stratified groups (Wilcoxon T tests; ≤1M to 6M **p=0•0046; others not significant [ns; p>0•05]).