Figure 1:

Comparison of T-cell responses to SARS-CoV-2 spike and structural proteins measured by in-house PITCH ELISpot and Oxford Immunotec T-SPOT assay. (A) T-cell responses to SARS-CoV-2 spike in naïve and previously infected healthcare workers reported by three panels: PITCH total spike (S1+S2), Oxford Immunotec Panel 1 + 2 (diagnostic S1 + S2), and Oxford Immunotec Panel 14 (total spike). Friedman test was used for statistical analysis between the three panels. (B) T-cell responses to SARS-CoV-2 membrane (M) and nucleocapsid (NP) in naïve and previously infected healthcare workers reported by PITCH ELISpot and Oxford Immunotec (OI) T-SPOT assay. Wilcoxon test was used for statistical analysis between samples matched across both assays, and Mann–Whitney test was used to compare naïve and previously infected T-cell responses within subgroups. (A,B) T-cell responses are quantified by spot-forming units (SFU) per 10⁶ peripheral blood mononuclear cells (PBMCs). Healthcare workers received phlebotomy 10 weeks post 1st dose (1 dose + 10 weeks) and/or 4 weeks post 2nd dose (2 doses + 4 weeks). All samples are matched across both assays (three panels for spike and 2 for M + NP T-cell responses). At 1 dose + 10 weeks, n = 41 for naïve samples and n = 14 for previously infected samples. At 2 doses + 4 weeks, n = 75 for naïve samples and n = 24 for previously infected samples. Infection status at time of first vaccine, as defined by available PCR and serology data: grey symbols = naïve HCWs and red symbols = HCWs previously infected with SARS-CoV-2. Median T-cell responses are stated immediately above each column and marked by a horizontal line on each column, and interquartile range is represented by error bars.