Fig. 1

Kinetics of spike-specific peripheral blood mononuclear cell responses. Cellular immune responses to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein, as examined by measuring (a) interferon (IFN)-γ, (b) tumor necrosis factor (TNF), (c) interleukin (IL)-2, (d) IL-6, (e) IL-10, and (f) IL-4 secreted from the spike protein peptide-stimulated peripheral blood mononuclear cells of participants before and six months after the primary vaccination and three months after the booster vaccination. Participants are stratified into three subgroups: healthcare workers (HW), outpatients (OP), and residents of long-term care facilities (LTCF). Each dot represents an individual participant, and the lines indicate corresponding pairs. The levels of each cytokine are logarithmically transformed. Boxes span the interquartile range; the line within each box denotes the median, and the whiskers are the largest and smallest values within the range of ±1.5-fold in the interquartile range from the first and third quartiles. P values were determined using one-sample Wilcoxon test with Bonferroni correction for multiple comparisons. N.S.; not significant