KNG1 and COVID-19: As far as the bradykinin mean concentration is concerned, we observed a statistically significant lower concentration (p < 0.0001) of bradykinin among 15 patients in the COVID-19 group (156.4 ± 129.8 pg ml−1) than in the 21 healthy individuals on control group (9,929 ± 8,368 pg ml−1).