Fig. 2

Minimal detection of spike-specific T cell responses after COVID-19 mRNA vaccine administration or COVID-19 infection, but readily detectable responses after enrichment by PBMC culture with mRNA-1273 vaccine in persons after lung transplantation. Spike-specific T cells in blood of lung transplant recipients were assayed by intracellular cytokine staining for IFN-γ production by flow cytometry after exposure to pooled peptides spanning the spike protein. 21 COVID-19-naïve persons were evaluated after completion of primary vaccination with two doses of mRNA COVID-19 vaccines without a third booster dose (range 42 to 160 days after second dose, mean 71 days, first column), 19 COVID-19-naïve persons were evaluated after primary vaccination and a third “booster” vaccination dose (range 8 to 50 days after booster vaccination, mean 17 days, second column), and 8 persons who had had COVID-19 (with or without vaccination, third column) were evaluated