Fully Vaccinated Patients With Multiple Myeloma: Rates of SARS–CoV-2 Breakthrough Infection and Hospitalization

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In a U.S. cohort study reported in JAMA Network Open, Wang et al found that fully vaccinated patients with multiple myeloma were at increased risk of breakthrough SARS–CoV-2 infection, and that those with breakthrough infection were more likely to be hospitalized vs fully vaccinated persons without cancer.

Study Details

The study used the cloud-based TriNetX Analytics network platform to access de-identified patient electronic health records from 63 health-care organizations in the United States. The study population included 507,288 patients who had:

  • Recent medical encounters with health-care organizations since December 1, 2020
  • Documented evidence of full vaccination with Pfizer-BioNTech (two doses), Moderna (two doses), or Johnson & Johnson (one dose) vaccines between December 1, 2020, and October 8, 2021
  • No prior COVID-19 infection.

Key Findings

Among 1,182 vaccinated patients with multiple myeloma, 77% received BioNTech, 22.2% Moderna, and 0.8% Johnson & Johnson vaccines, compared with 90%, 8.5%, and 1.4%, respectively, of 506,106 patients without cancer.

Among the vaccinated multiple myeloma patient population, 33.8% had monoclonal gammopathy of undetermined significance (MGUS); 11.7% were in relapse; 88.7% had never achieved remission; 60.0% had received chemotherapy, 50.3% had received targeted therapy, and 12.1% had undergone radiation therapy; 26.5% had undergone stem cell transplantation; and mean blood lymphocyte count was 2.08 × 109/L.

Breakthrough infection was observed in 15.4% of the multiple myeloma patient population vs 3.9% of the noncancer population. Among the 187 patients with multiple myeloma who had breakthrough infection, 34.8% had MGUS, 15.5% were in relapse, 86.6% had never achieved remission, 64.2% had received chemotherapy, 54.3% had received targeted therapy, 11.2% had undergone radiation therapy, 27.8% had undergone stem cell transplantation, and mean blood lymphocyte count was 1.63 × 109/L.  

In propensity score–matched analysis—including demographics, adverse socioeconomic determinants of health, transplantation procedures, comorbidities, vaccine types, and medications—patients with multiple myeloma remained at significantly increased risk for breakthrough infection (hazard ratio [HR] = 1.34, 95% confidence interval [CI] = 1.06–1.69). Among patients with breakthrough infection, estimated probability of hospitalization was 34.4% for patients with multiple myeloma vs 4.5% for noncancer patients (HR = 15.9, 95% CI = 6.2–40.3).

The investigators concluded, “This study found that patients with [multiple myeloma] were at increased risk of breakthrough infections, and that breakthrough infections were associated with increased risk for hospitalization. These findings raise consideration for the development and implementation of enhanced mitigation strategies and the need for studies to evaluate the timing and impact of vaccine boosters in this unique, immunosuppressed population.”

Nathan A. Berger, MD, of the Center for Science, Health, and Society, School of Medicine, Case Western Reserve University, is the corresponding author for the JAMA Network Open article.

Disclosure: The study was supported by the National Cancer Institute, American Cancer Society, and others. For full disclosures of the study authors, visit

The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.