Multiple myeloma (MM) is a blood cancer characterized by the uncontrolled growth of malignant plasma cells within the bone marrow. While these plasma cells normally produce protective antibodies, their cancerous proliferation disrupts the body’s ability to fight infection. The combination of the underlying disease and its necessary treatments creates an elevated risk profile for patients who contract COVID-19. Extensive clinical data confirms that survival is a common outcome, though the risk of severe illness is significantly higher than in the general population.
Survival Rates and Outcomes
A person with multiple myeloma can survive COVID-19, but the risk of a severe outcome is substantially increased. Early in the pandemic, studies reported a high overall mortality rate for MM patients hospitalized with COVID-19, often ranging from 27% to 33%, which was notably higher than for the general hospitalized population. For those requiring mechanical ventilation, the death rate reached up to 80% to 100% in some early reports.
Survival rates have since improved dramatically due to widespread vaccination and targeted antiviral treatments. Data showed that overall mortality for MM patients decreased significantly, dropping from approximately 34% to 10% over time. This improvement highlights the effectiveness of contemporary medical management. Patients whose myeloma is in complete or very good partial response have superior outcomes compared to those with active, progressive, or relapsed disease. Advanced age, kidney disease, and other underlying health conditions are consistently associated with a higher risk of adverse outcomes.
How Multiple Myeloma Weakens Immune Response
The underlying pathology of multiple myeloma creates a state of immune vulnerability that predisposes patients to severe infections. The disease originates from plasma cells, which produce antibodies to neutralize threats like viruses and bacteria. Cancerous myeloma cells crowd out and suppress healthy plasma cells, leading to hypogammaglobulinemia, where levels of functional, protective antibodies are low.
This deficiency prevents the body from mounting an effective initial defense against SARS-CoV-2, increasing susceptibility to severe disease. While myeloma cells produce large amounts of a non-functional monoclonal protein (M-protein), this does not help fight the virus and can sometimes cause organ damage. Furthermore, the disease process itself impairs the function of other infection-fighting immune cells, such as T-cells and B-cells. This immune dysregulation results in a slower and less robust response, allowing the infection to become more prolonged and severe.
COVID-19 Risks Associated with Specific Therapies
Many common multiple myeloma treatments further increase a patient’s vulnerability to COVID-19. Corticosteroids, such as dexamethasone, are a backbone of nearly all MM treatment regimens and cause broad immunosuppression. Dexamethasone reduces the activity of various immune cells, increasing the risk of contracting the virus and experiencing a more aggressive infection.
Other novel agents, including proteasome inhibitors and immunomodulatory drugs, also contribute to immunosuppression. While necessary to control the cancer, these therapies impair the body’s ability to generate robust immune memory and weaken vaccine response. Specific monoclonal antibody therapies, like those targeting CD38, can deplete certain immune cells and temporarily interfere with the effectiveness of a vaccine or natural immunity.
A recent autologous stem cell transplant (ASCT) represents a period of profound, temporary immunosuppression, especially in the first few months post-transplant while the immune system rebuilds. The intensity of the procedure necessitates strict infection precautions. When an active COVID-19 infection occurs, doctors typically must temporarily pause the anti-myeloma therapy until the infection resolves. This necessary pause in cancer treatment can sometimes lead to disease progression, challenging the balance between cancer control and viral management.
Prevention and Acute Care Protocols
A proactive approach to both prevention and acute treatment is standard care for multiple myeloma patients due to their high-risk profile. Vaccination against SARS-CoV-2 is paramount, even though the immune response is often suboptimal compared to healthy individuals. Studies confirm that MM patients frequently require additional vaccine doses beyond the standard primary series to achieve adequate protection.
Many MM patients showed little or no antibody response after the initial two doses, but a third dose often proved highly effective, converting a poor response to a protective one. Staying up-to-date with all recommended boosters and additional doses is necessary to maintain the highest level of immunity possible. Non-pharmaceutical interventions like consistent masking and avoiding high-risk exposures remain important protective measures.
Upon diagnosis of an active COVID-19 infection, MM patients are prioritized for specific antiviral medications. The oral antiviral Nirmatrelvir/ritonavir (Paxlovid) is a first-line treatment for mild-to-moderate COVID-19 and must be started within a few days of symptom onset to be most effective. Intravenous Remdesivir is another therapeutic option, sometimes used when oral antivirals are contraindicated due to drug-drug interactions with myeloma medications. Careful consultation with the oncology team is necessary to manage these medications and coordinate the temporary interruption of myeloma therapy.