Serological Response in Lung Transplant Recipients after Two Doses of SARS-CoV-2 mRNA Vaccines

The immunological effectiveness of SARS-CoV-2 mRNA vaccines in lung transplant (LT) recipients is largely unknown. Thus, we assessed the effect of Pfizer-BioNTech and Moderna mRNA vaccines’ two-dose (2D) regimen on humoral responses in immunocompromised lung transplant (LT) recipients. About 25% (18/73) of SARS-CoV-2 uninfected-LT patients generated positive spike-IgG response following 2D of vaccines, with 36% (9/25) in the Moderna cohort and only 19% (9/48) in the Pfizer cohort. 2D in LT patients elicited significantly lesser median IgG _SP response (1.7 AU/mL, 95% CI: 0.6-7.5 AU/mL) compared to non-transplanted, uninfected naïve subjects (14209 AU/mL, 95% CI: 11261-18836 AU/mL) (p<0.0001). In LT patients, Moderna-evoked seropositivity trend was higher by 23-fold than Pfizer. 2D COVID-19 vaccination elicits a dampened serological response in LT patients. Whether assessing other arms of host immunity combined with higher vaccine dose can better capture and elicit improved immunogenicity in this immunocompromised population warrants investigation.