Can a COVID-19 Vaccine Help Treat Cancer?
Recent research from the United States has sparked interest in whether COVID-19 vaccines, particularly mRNA vaccines, might influence cancer outcomes when given alongside immunotherapy. In a retrospective analysis of more than 1,000 patients with advanced lung cancer or metastatic melanoma, researchers found that those who received a COVID-19 mRNA vaccine within 100 days of starting immunotherapy lived longer on median than those who did not receive the vaccine. While the results are striking, experts caution that the study shows association, not causation, and controlled trials are needed to confirm any direct therapeutic effect.
What the Study Found
The study, published in Nature, analyzed patient records to assess whether vaccination could impact responses to cancer immunotherapy. Among patients with advanced lung cancer, vaccination was associated with a near doubling of median survival—rising from about 20.6 months to approximately 37 months. For individuals with metastatic melanoma, median survival increased from 26.7 months to a range of 30 to 40 months, with some patients potentially doing even better.
How Might an mRNA Vaccine Help the Immune System?
Assoc Prof Seth Cheetham, Deputy Director of the BASE mRNA Facility at the University of Queensland, explains a possible mechanism. He suggests that mRNA vaccines can rapidly “wake up” the immune system, prompting a stronger, broader immune response. Animal models in related studies have shown that this surge can prime cancer-fighting immune cells to infiltrate tumours and attack malignant cells more effectively.
While this is a plausible explanation, Cheetham notes that researchers are not claiming the COVID vaccines are cancer therapies. Instead, the findings hint at a practical and potentially inexpensive way to boost immunotherapy effectiveness using an existing vaccine. In the context of cost and logistics, this could be important if confirmed by more rigorous trials.
Limitations and Next Steps
Experts emphasise that the retrospective design of the study means the results could reflect other factors that differ between vaccinated and unvaccinated groups. Possible confounders include health status, access to care, and treatment choices. Randomised controlled trials are essential to determine whether the vaccine causally improves cancer outcomes or simply associates with factors that influence survival.
Dr. Cheetham and other researchers point to the potential of combining vaccines with immunotherapies, but they caution against overinterpreting current data. If future trials confirm benefit, the approach could offer a readily accessible strategy to enhance cancer treatment without introducing new drugs or complex manufacturing processes.
What It Means for Patients Today
For patients already navigating advanced cancers, the findings may provide some reassurance about getting a COVID-19 vaccine during treatment. Independent of any potential cancer-specific benefit, vaccines continue to offer protection against COVID-19 infection, hospitalization, and death—an important consideration for individuals with compromised health undergoing immunotherapy.
COVID Vaccines Remain Important for Public Health
Separately, updated COVID vaccines continue to show effectiveness against infection and severe outcomes, with protection strongest shortly after vaccination and gradually waning over time. Health authorities advocate annual vaccination to maintain protection, especially for older adults and those with chronic conditions.
Bottom Line
The Nature study presents an intriguing possibility that existing mRNA vaccines could augment cancer immunotherapy, potentially improving survival in some patients. However, the evidence is preliminary and retrospective. Confirmatory, controlled trials are needed to determine causality and to guide clinical practice. Until then, vaccination remains a key tool for preventing COVID-19 and its complications, alongside ongoing cancer treatments.
