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

Background: Lung-transplant (LT) recipients are at high risk for COVID-19 due to immunosuppression and respiratory tropism of SARS-CoV-2. The information on the effect of COVID-19 mRNA vaccines to elicit immunogenic responses after a two-dose (2D) regimen in LT recipients is sparse. Thus, we assessed the effect of Pfizer-BioNTech and Moderna mRNA vaccines' 2D regimen on anti-spike responses in immunocompromised LT recipients. Methods: We utilized serum samples from LT recipients vaccinated for SARS-CoV-2 with 2D of either the Pfizer-BioNTech or Moderna vaccines and 2D-vaccinated naive (non-transplanted and non-exposed to COVID-19) group. Antibody responses were assessed using the FDA-approved SARS-CoV-2 anti-nucleocapsid protein IgG assay (IgG(NC)), the SARS-CoV-2 anti-spike protein IgM assay (IgM(SP)), and the SARS-CoV-2 anti-spike protein IgG II assay (IgG(SP)). CD4+ T-cell activity was assessed as a marker of immune competence using the ImmuKnow (R) assay. Results: About 25% (18/73) of SARS-CoV-2 uninfected-LT patients generated a 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 a significantly lesser median IgG(SP) response (1.7 AU/mL, 95% CI: 0.6-7.5 AU/mL) compared to non-transplanted, uninfected naive subjects (14,209 AU/mL, 95% CI: 11,261-18,836 AU/mL; p < 0.0001). In LT patients, the Moderna-evoked seropositivity trend was higher than Pfizer. Conclusion: 2D COVID-19 vaccination elicits a dampened serological response in LT patients. Whether assessing other arms of host immunity combined with a higher vaccine dose can better capture and elicit improved immunogenicity in this immunocompromised population warrants investigation.

Automated summary

Lung-transplant recipients are at high risk for COVID-19 due to their immunosuppressed state and the respiratory tropism of SARS-CoV-2. The study found that the serological response in LT patients after receiving two doses of COVID-19 vaccine is dampened, with Moderna vaccine showing a higher trend of seropositivity compared to Pfizer.