OXT and COVID-19: Patients in the mild or moderate COVID-19 group had the highest levels of oxytocin concentration during each visit (first visit: 21.78 ± 8.28 ng/mL; second visit: 29.87 ± 10.32 ng/mL; third visit: 35.36 ± 18.14 ng/mL), with the lowest levels observed in the severe COVID-19 group (first visit: 8.02 ± 1.96 ng/mL; second visit: 11.16 ± 2.98 ng/mL; third visit: 17.45 ± 5.40 ng/mL) compared to the control group (first visit: 19.98 ± 4.70 ng/mL; second visit: 25.09 ± 5.33 ng/mL; third visit: 30.94 ± 6.93 ng/mL) (Figure 3b).