Interestingly, our seroprevalence results showed that the GMC and positivity rate of anti-PT IgG antibodies in subjects were significantly higher in post-COVID-19 than in pre-COVID-19 [19.1% vs 5.4%, 20.54 (95% CI: 16.98–24.09) vs. 14.68 (95% CI: 13.20–16.16)], and the anti-PT IgG antibody concentration ≥100 IU/ml significantly increased post-COVID-19. Here, F2 is linked to COVID-19.