Study shows vaccinated multiple myeloma patients at greater risk of breakthrough SARS-CoV-2 infections

Patients with existing immunological complications and malignancies have been inferred to be at greater risk of developing severe coronavirus disease 2019 (COVID-19). This holds true for patients with multiple myeloma (MM).

Study: Risks of SARS-CoV-2 Breakthrough Infection and Hospitalization in Fully Vaccinated Patients With Multiple Myeloma. Image Credit: creativeneko/ Shutterstock

Recent studies have shown a lower rate of seroconversion after vaccination with messenger RNA (mRNA) anti-SARS-CoV-2 vaccines in patients with MM and other hematological malignancies.

However, the risk and outcomes of SARS-CoV-2 breakthrough infection in vaccinated patients with MM remain unknown.

Researchers recently published a study in JAMA assessing the risks of patients with MM to breakthrough infections after completing their vaccination schedule compared to those without any form of cancer.

Study details

Researchers used the cloud-based TriNetX Analytics network platform to access de-identified patient electronic health records (EHRs) from 63 health care organizations in the United States. The study population comprised of 5,07,288 patients who fulfilled the following inclusion criteria:

  1. had a recent medical encounter(s) with health care organizations since December 1, 2020;
  2. had documented evidence of full vaccination in the EHRs (Pfizer-BioNTech, Moderna, or Johnson & Johnson vaccine) between December 1, 2020, and October 8, 2021;
  3. and had no prior COVID-19 infection.

Among 1,182 vaccinated patients with MM, 33.8 percent had monoclonal gammopathy of undetermined significance (MGUS), 11.7 percent were in relapse, 88.7 percent had never achieved remission, 60.0 percent had chemotherapy, 50.3 had targeted therapy, 12.1 had radiation therapy, and 26.5 had stem cell transplant; mean (SD) blood lymphocyte count was 2.08 × 109 /L (12.2 × 109 /L).

Among 187 patients with MM with SARS-CoV-2 breakthrough infections, 34.8 had MGUS, 15.5 were in relapse, 86.6 had never achieved remission, 64.2  had chemotherapy, 54.3 had targeted therapy, 11.2 had radiation therapy, and 27.8  had stem cell transplant; mean (SD) blood lymphocytes count was 1.63 × 109 /L (2.01 × 109 /L).

The overall risk of SARS-CoV-2 breakthrough infections was 15.4 in the MM population and 3.9 in the non-cancer population. After propensity score matching for demographics, adverse socioeconomic determinants of health, transplant procedures, comorbidities, vaccine types, and medications, patients with MM remained at significantly increased risk for breakthrough infections compared with matched patients without cancer (Hazard Ratio, 1.34). The estimated probability of hospitalization at the end of the time window (October 8, 2021) was 34.4 for patients with MM.


This study found that patients with MM were at increased risk of breakthrough infections and subsequent hospitalization. These findings raise consideration for the development and implementation of enhanced mitigation strategies. Entailing more studies to evaluate the timing and impact of vaccine boosters in such an immunosuppressed population can also help improve health outcomes for patients.

Journal reference:
  • Wang, L., Berger, N. and Xu, R. (2021) "Risks of SARS-CoV-2 Breakthrough Infection and Hospitalization in Fully Vaccinated Patients With Multiple Myeloma", JAMA Network Open, 4(11), p. e2137575. doi: 10.1001/jamanetworkopen.2021.37575

Posted in: Medical Science News | Medical Research News | Disease/Infection News

Tags: Blood, Cancer, Cell, Chemotherapy, Coronavirus, Coronavirus Disease COVID-19, Health Care, Lymphocyte, Multiple Myeloma, Myeloma, Radiation Therapy, RNA, SARS, SARS-CoV-2, Transplant, Vaccine

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Sreetama Dutt

Sreetama Dutt has completed her B.Tech. in Biotechnology from SRM University in Chennai, India and holds an M.Sc. in Medical Microbiology from the University of Manchester, UK. Initially decided upon building her career in laboratory-based research, medical writing and communications happened to catch her when she least expected it. Of course, nothing is a coincidence.

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