Our recent work showed COVID BALF from vaccinated individuals contained significantly lower concentration of fibrinogen and prothrombin, suggesting a potential benefit of vaccination being lower risk of fibrin clotting and acute lung injury. As our previous mass spec-based proteomic ID approach showed the presence over 500 proteins in BALF, we propose to compare the presence of various inflammatory, coagulation factors between vaccinated and unvaccinated BALF through proteomic approach. The research has potential to reveal the benefit of vaccination to prevent lung fibrosis.