PITCH Bivalent COVID-19 vaccine
Description
This study explored the impact of ancestral/BA.1 bivalent mRNA booster vaccination (Autumn 2022) on peripheral and nasal antibody and T-cell responses to SARS-CoV-2 in 133 UK healthcare workers (PITCH study). Participants had received a primary course of mRNA vaccine (BNT162b2, Pfizer/BioNTech or mRNA-1273, Moderna) or viral vector vaccine (AZD1222, Oxford/AstraZeneca), followed by a third “booster” dose of mRNA vaccine (BNT162b2, mRNA-1273). A subset of participants then went on to receive a fourth dose of mRNA ancestral/BA.1 bivalent vaccine (Pfizer/BioNTech, Moderna). Participants underwent phlebotomy for assessment of immune responses six (median 191 days, IQR 183-201) months and twelve (median 358 days, IQR 341-370) months after the third dose of vaccine, one (median 30 days, IQR 27-34) month and six (median 190 days, IQR 180-214) months after the fourth dose of vaccine (ancestral/BA.1 bivalent) and for those participants who did not receive a fourth dose a sample was taken at eighteen (median 546 days, IQR 525-563) months after the third dose. Figure 2: Serology (Mesoscale Discovery platform) and T cell (IFN-g ELISpot) data assessing the impact of the ancestral/BA.1 bivalent booster dose (2022) on circulating antibody and T cell responses to SARS-CoV-2 in HCW. Data generated from the MSD serology assays are expressed in arbitrary units (AU)/mL. ELISpot values are expressed as spot-forming units per million (SFU/106) PBMCs. Figure 3: Broadening of circulating IgG to variant of concern spike upon receiving the ancestral/BA.1 bivalent vaccine. Data were generated from MSD serology assays and are expressed in arbitrary units (AU)/mL. Figure 4: Transient broadening of neutralising circulating SARS-CoV-2 antibodies upon vaccination. The percentage of focus reduction was calculated and IC50 was determined using the probit program from the SPSS package. Figure 5: Nasal epithelial lining fluid (NELF) IgG to SARS-CoV-2 spike is boosted upon vaccination with IgA levels being maintained. Data generated from the MSD serology assays are expressed in arbitrary units (AU)/mL. Figure 6: Increased breadth of nasal IgG to SARS-CoV-2 VOC spike. Data generated from the MSD serology assays are expressed in arbitrary units (AU)/mL. Figure 7: Cross-reactive T cell responses to SARS-CoV-2 VOC spike. IFN-g T cell responses (in blood) are expressed as spot-forming units per million (SFU/106) PBMCs.