Figure 2.

Neutralizing antibody titres in previously infected (n=23) and uninfected healthcare workers (n=13) tested at V0, V1_20, V2_20 and V2_90, and in unvaccinated HCWs (n=9) tested at N_60, N_300 and N_390.

Data are reported as individual ID₅₀ values and as median value at each study time

The same symbols indicate the same HCWs at different time points

ID₅₀: reciprocal value of the sample dilution that showed a 50% protection of virus cytopathic effect

V0: before receiving the first dose

V1_20: 20±2 days after the first dose

V2_20: 20±3 days after the second dose

V2_90: 90±2 days after the second dose

N_60: baseline, after about 2 months from diagnosis

N_300: after a median of 291 days from diagnosis

N_390: after a median of 394 days from diagnosis