Fig. 5.

Repeat injection of Comirnaty marginally induced PEG-specific antibodies. The concentration of anti-PEG antibodies in mouse plasma was assessed on day 28 after each vaccination. (A) A comparison of the concentrations of anti-PEG IgG before vaccination and after 3 doses of Comirnaty in group 1 (◯) (n = 10). (B) A comparison of the concentrations of anti-PEG IgM before vaccination and after 3 doses of Comirnaty in group 1 (◯) (n = 10). (C) A comparison of the concentrations of anti-PEG IgG before vaccination and after 3 doses of Comirnaty in group 2 (△) (n = 10). (D) A comparison of the concentration of anti-PEG IgM before vaccination and after 3 doses of Comirnaty in group 2 (△) (prevax and 1st dose, n = 10; 2nd dose and 3rd dose, n = 9). (E) Cross-comparison of the fold-change (log₁₀) of anti-PEG IgG and IgM (F) among the 3 cohorts: naïve groups (prevax/3rd dose, n = 10), group 1 (prevax/3rd dose, n = 10), and group 2 (prevax/3rd dose, n = 9). (E and F) Data were derived by the nonparametric Kruskal–Wallis test with Dunn’s multiple comparisons test (n = 10 in naïve group and group 1; n = 9 in group 2). Prevax, prevaccination; 3rd dose, 3rd dose of Comirnaty vaccination.