https://www.researchgate.net/publication/344210822_Lysine_Therapy_for_SARS-CoV-2
A report in 2016 which included L-lysine showed a positive clinical outcome against MERS-CoV in-vitro, although not SARS-CoV-2 which had not yet appeared. (5) Given that L-lysine appears to operate universally within the herpes viral family, it would be reasonable to expect it to work in the entire SARS viral family. Our clinical experience demonstrates effectiveness against SARS-CoV-2, and it is therefore likely to work in MERS-CoV and other members of the Coronavirus family in-vivo. Dietary lysine
2 deficiency is known to impair both antibody responses and cell-mediated immune response. (7) Lysine improves the immune system. (4)
One of the most important observations in relation to lysine was the incredibly short time to eliminate/reduce fever presumably due to extinguishing the associated cytokine storm.