SARS-CoV-2 Vaccine-Induced Immune Responses among Hematopoietic Stem Cell Transplant Recipients

Abstract

ABSTRACT Background Although SARS-CoV-2 vaccination reduces the risk and severity of coronavirus disease 2019 (COVID-19), several variables may impact the humoral response among patients undergoing hematopoietic stem cell transplantation (HSCT). Methods A retrospective chart review was conducted among SARS-CoV-2 vaccinated HSCT recipients between 2020 and 2022 at a single center in Boston, Massachusetts. Patients >18 years who received dose(s) of Pfizer, Moderna, or J&J vaccine were included. Anti-Spike (S) IgG titer levels were measured using the Roche assay. Responders (≥0.8 U/mL) and non-responders (.8 U/mL) were categorized and analyzed. Multivariable linear and logistic regression were used to estimate the correlation coefficient and odds ratio of response magnitude and status. Results Of 152 HSCT recipients, 141 (92.8%) were responders with a median anti-S IgG titer of 2500 U/mL (IQR: 107.9, 2500) at a median of 80.5 days (IQR: 36, 153.5) from last dose regardless of the number of doses received. Higher quantitative titers were associated with receipt of more vaccine doses (Coeff=205.79; 95% CI 30.10, 381.47; p= 0.022), being female (coeff= -343.5; 95% CI -682.6, -4.4; p=0.047), being younger ( years) (coeff= -365.2; 95% CI -711.3, 19.1; p=0.039) and not being on anti-CD20 therapy (coeff= -1163.7; 95% CI -1717.7, -609.7; p=0.001). Being male (OR=0.11; CI 0.01, 0.93; p=0.04) and on anti-CD20 therapy (OR=0.16; CI 0.03, 0.70; p=0.016,) were associated with Non-responders. Conclusion Overall, most HSCT recipients had high SARS-CoV-2 antibody responses. More vaccine doses improved the magnitude of immune responses. Anti-S IgG monitoring may be useful for identifying vaccine failures. Keywords COVID-19 vaccine · Anti-spike protein · Allogeneic HSCT · Autologous HSCT .Transplant