Comparative data of FL-OPN (A) and Ud-OPN (B) between dengue, leptospirosis, and COVID-19 infections. The abbreviations are DF, dengue fever; DHF, dengue hemorrhagic fever. Data are from references [9,111,115]. ****; p < 0.0001, ***; p < 0.001, **; p < 0.01, *; p < 0.05.