Introduction: Due to functional hypogammaglobulinemia, multiple myeloma patients are at increased risk for infection and generally have poorer responses to vaccines. In this study, we examined antibody responses after complete COVID-19 vaccination in patients with plasma cell dyscrasias, most of whom were receiving treatment.
Patients and Methods: Real world study of consecutive patients with multiple myeloma and other plasma cell dyscrasias (PCD) were evaluated after complete vaccination with either the 2-shot mRNA vaccines from BioNTech and Moderna or the 1-shot adenoviral vector vaccine from Johnson & Johnson (J&J). Patients received vaccines 1-4 months before antibody testing without controlling for the type of vaccine or the timing of drug therapy. Patients with a clinical history or antibody evidence of prior infection were excluded. Anti-nucleocapsid and quantitative anti-spike antibody levels were measured with the Roche Elecys assay.
Results: 95% of patients had detectable antibody responses. Multivariate analysis showed that higher age, ongoing anti-CD38 monoclonal antibody therapy and the J&J vaccine negatively affected quantitative response. A small number of ineffectively vaccinated patients receiving IVIG subsequently had detectable nucleocapsid and spike antibodies confirming the presence of the latter in currently administered IVIG.
Conclusions: Nearly all PCD had detectable anti-spike antibodies after vaccination but age, anti-CD38 monoclonal antibody therapy, and the single-shot J&J vaccine negatively affected responses. In patients who received the J&J vaccine, second doses or heterologous mRNA vaccines should be tested. Quantitative antibody testing might make future management more rational, particularly in patients with poor responses.