Beneficial effects of Vitamin C and L-Arginine in the treatment of post-acute sequelae of COVID-19.

We thank Dr. Ku and collaborators for their interest in our work on COVID-19 and long-COVID.

We agree on the fact that BMI, smoking, COPD, and other factors may increase the risk of post-acute sequelae of COVID-19 (PASC) [1]. However, these considerations are not pertinent to our study, in which we did not assess the risk of developing Long-COVID [2]; in fact, all the patients enrolled in our study had Long-COVID when the survey was administered. The LINCOLN (-Arginine and Vitamin C improve Long-COVID) survey [3] was designed to determine whether a supplementation combining Vitamin C (to reduce oxidation) and L-Arginine (to improve endothelial function [4]) could have favorable effects in patients with Long-COVID. Several investigators have reported that vaccination reduces the risk of developing PASC [5], [6], but, as mentioned above, all patients who received the LINCOLN survey had PASC; additionally, it is important to note that in Italy more than 90% of the population has received at least two doses of COVID-19 vaccine. Finally, recall bias and non-response bias do not apply to our study, since our LINCOLN questionnaire was administered only once.

Funding

None.

Declarations of Competing Interest

None.