Patients with multiple myeloma (MM), particularly those receiving anti-CD38 treatment, do not achieved full protection from the BNT162b2 mRNA vaccine at 5 weeks after the first shot compared with patients with myeloproliferative malignancies (MPM) or elderly patients without cancer. These results were published in the Journal of Hematology & Oncology.

As part of a single center prospective cohort study, the researchers evaluated 42 patients with MM and 50 patients with MPM (20 with chronic myeloid leukemia, 30 with myeloproliferative neoplasms) who were actively undergoing anticancer treatment. They planned to measure antibody titers, seroconversion rates, and trends in patients with solid tumors and hematologic malignancies and compare them against 36 patients older than 80 (control group). The patients were evaluated for anti-SARS-CoV-2-neutralizing IgG titer on the day of the first injection of the mRNA vaccine, on the day of the second injection 3 weeks later, and at the 5-week mark.

At 5 weeks, patients with multiple myeloma experienced a less robust response (geometric mean concentration [GMC] of IgG, 106.7 AU/mL) than either the control group (353.3 AU/mL) or even the patients with MPM (172.9 AU/mL). The patients with MPM achieved seroconversion levels of 88% (P =.038) after the second dose; the control group achieved a 100% seroprotection rate at the cut-off point of 15 AU/mL. But patients with MM only achieved a seroconversion rate of 78.6% after the second dose (P =.003).

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“[T]he fact that not all MM patients responded to vaccine, and that those who responded did it not robustly, poses great concerns and turns to the opportunities offered by the new mRNA vaccination platforms,” the researchers wrote. Further studies are needed to determine if repeated booster of mRNA vaccine and at what intervals may improve humoral response.

This less-than-robust response led the researchers to suggest IgG titer monitoring and boosters for patients with MM. Those undergoing treatment with anti-CD38 monoclonal antibodies also should maintain social distancing and mask wearing regardless of vaccination status, and cohabiting family members need to be vaccinated.

Study limitations included a limited number of patients and a limited observation period, as well as a lack of parallel investigations on the T-cell response which does not enable drawing a firm conclusion as to whether the patients really developed true protection against COVID-19.


Pimpinelli F, Marchesi F, Piaggio G, et al. Fifth-week immunogenicity and safety of anti-SARS-CoV-2 BNT162b2 vaccine in patients with multiple myeloma and myeloproliferative malignancies on active treatment: preliminary data from a single institution. J Hematol Oncol. 2021;14(1):81.