SARS-CoV-2 Infection in Fully Vaccinated Multiple Myeloma Patients
Overview
Five fully vaccinated patients with multiple myeloma (MM) or smoldering MM (SMM) developed SARS-CoV-2 infection despite receiving two doses of the BNT162b2 mRNA vaccine. Infections occurred predominantly with the Delta variant, after a median of 86 days post-vaccination, with variable clinical presentations ranging from asymptomatic to mild symptoms.
Background
Patients with hematologic malignancies, including MM, are at increased risk of severe COVID-19 and higher mortality. MM patients exhibit immune dysregulation due to disease and treatment, leading to suboptimal vaccine responses. Initial vaccine trials excluded these patients, so vaccine efficacy and durability remain uncertain. Prior studies have shown reduced antibody responses, especially in those receiving anti-CD38 or anti-BCMA therapies.
Data Highlights
Patient
Age/Sex
MM Status
Comorbidities
Days from 2nd Dose to Infection
Variant
Symptoms
1
76/F
IgA λ SMM
Hypertension, obesity, COPD, renal failure
21
Alpha (B.1.1.7)
Diarrhea
2
71/F
IgG k MM, stage II ISS-R
Diabetes, hypothyroidism
83
Delta (B.1.617.2)
Dry cough
3
56/M
IgG λ SMM
Kidney transplant, hypertension
129
Delta (B.1.617.2)
Fever, pneumonia
4
70/M
Relapsed IgG k MM, stage II ISS
Hypertension
86
Delta (B.1.617.2)
Asymptomatic
5
54/F
IgG k MM, stage I ISS
Hypothyroidism
140
Delta (B.1.617.2)
Fever
Key Findings
Five MM/SMM patients developed SARS-CoV-2 infection despite full vaccination with BNT162b2 mRNA vaccine.
Infections occurred between 21 and 140 days after the second vaccine dose, median 86 days.
One patient was infected with Alpha variant; the other four with Delta variant, reflecting local epidemiology.
Clinical presentations varied from asymptomatic to mild symptoms such as diarrhea, cough, fever, and pneumonia.
One patient was a kidney transplant recipient under immunosuppression, highlighting additional risk factors.
Some patients were on active MM treatment, including daratumumab-based regimens, which may impair vaccine response.
Clinical Implications
MM patients remain at risk for SARS-CoV-2 infection despite full vaccination, particularly with emerging variants like Delta. Clinicians should maintain vigilance and consider additional protective measures, including booster vaccinations and continued infection control. Monitoring antibody responses and adjusting treatment timing may help optimize vaccine efficacy in this population.
Conclusion
SARS-CoV-2 infection can occur in fully vaccinated MM patients, often with mild disease, but immune dysregulation and treatment factors may contribute to vulnerability. Further studies are needed to define optimal vaccination strategies and protective measures in this high-risk group.
