Correlation of donor characteristics and S‐RBD‐specific IgG antibody. (A) The S‐RBD‐specific IgG antibody level in non‐febrile (<37.5°C), mild‐febrile (37.5‐38.4°C), moderate‐febrile (38.5‐39.4°C), and extreme‐febrile (≥39.5°C) donors. (B) The S‐RBD‐specific IgG antibody level in donors with fevers lasting <3 days, 3‐7 days, and ≥8 days. (C) The S‐RBD‐specific IgG antibody level of donors <30 years old, 30‐39 years old, 40‐49 years old, and ≥50 years old. (D) The S‐RBD‐specific IgG antibody level in male and female donors. (E) The S‐RBD‐specific IgG antibody level of A, B, O, and AB blood type donors. The differences between the groups were analyzed using the Newman–Keuls test and values are presented as the mean ± SD. *p < 0.05, **p < 0.01; NS, nonsignificant.