The following is a summary of “Antibody response after third dose of COVID-19 mRNA vaccination in allogeneic hematopoietic stem cell transplant recipients is comparable to that in healthy counterparts,” published in the August 2023 issue of Hematology by Takagi et al.
Researchers started a retrospective study to measure antibody titer serially in 92 allogeneic hematopoietic stem cell transplantation (allo-HSCT) patients to determine the efficacy of SARS-CoV-2 mRNA vaccination.
They assessed 87 patients with a median age of 53 years (range 18–75) at the time of vaccination. The average duration between allo-HSCT and vaccination was 3.3 years (range, 0.5–15.7).
The results showed one month after the second dose, 80.5% of patients (70 patients) exhibited a positive response, while 19.5% (17 patients) showed a negative response (< 20 U/mL). Patients over 44 years showed negative responses, with low IgM levels being the main predictor of vaccine failure in the older ones. Examining 47 patients, antibody levels notably rose from a median of 18.3 U/mL to 312.6 U/mL after the third vaccination (P<0.01). Healthy individuals (n = 203) had a median antibody titer of 426.4 U/mL after the third vaccination, comparable to that of the patients (P=0.2). Despite previous vaccine failures with the initial two mRNA doses, patients showed increased antibody levels following the third mRNA vaccination.
Investigators concluded that allo-HSCT recipients should receive the mRNA vaccine regularly.