Patients with cancer who received mRNA-based COVID-19 vaccines within 100 days of starting immune checkpoint therapy were twice as likely to be alive three years after beginning treatment, according to new research led by The University of Texas MD Anderson Cancer Center.
The study, which included more than 1,000 patients treated between August 2019 and August 2023, was presented at the 2025 European Society for Medical Oncology (ESMO) Congress. The research was co-led by Dr. Steven Lin, Professor of Radiation Oncology, and Dr. Adam Grippin, Senior Resident in Radiation Oncology.
Vaccines Enhance Antitumor Immune Response
“This study demonstrates that commercially available mRNA COVID vaccines can train patients’ immune systems to eliminate cancer,” said Dr. Grippin. “When combined with immune checkpoint inhibitors, these vaccines produce powerful antitumor immune responses that lead to remarkable improvements in survival.”
As reported by medicalxpress, the team discovered that mRNA vaccines, originally designed for infectious diseases, could stimulate the immune system to recognize and destroy cancer cells. This effect was first observed by Dr. Grippin during his graduate research at the University of Florida, in the lab of Dr. Elias Sayour, where they developed personalized mRNA-based vaccines for brain tumors. Even when these mRNA vaccines did not specifically target tumor cells, they trained the immune system to attack cancer.
From Hypothesis to Clinical Evidence
Encouraged by these early findings, Drs. Lin and Grippin hypothesized that mRNA COVID vaccines might offer similar immune-boosting effects. The widespread use of these vaccines provided a unique opportunity to test this idea.
The researchers conducted a retrospective analysis of MD Anderson patients to evaluate whether those who received mRNA COVID vaccines had better outcomes than those who did not. The study showed that vaccinated patients lived significantly longer across multiple cancer types.
How mRNA Vaccines Amplify Immunotherapy
To explore the underlying mechanisms, the Lin and Sayour labs used preclinical models to study how mRNA vaccines interact with the immune system. They found that mRNA vaccines act like an immune alarm, putting the body on high alert to detect and attack cancer cells.
In response, cancer cells increase production of PD-L1, a protein that helps them evade immune attacks. Fortunately, immune checkpoint inhibitors—a major class of cancer drugs—are specifically designed to block PD-L1, preventing cancer cells from hiding. This combination creates a synergistic effect, allowing the immune system to launch a stronger, more effective attack on the tumor.
These findings were confirmed in both animal studies and human samples. Healthy volunteers who received mRNA vaccines showed increased immune activation, while tumor samples from vaccinated patients exhibited higher PD-L1 expression, reinforcing the preclinical observations.
Dramatic Survival Benefits Across Cancer Types
The study analyzed multiple cancer cohorts. Among 180 patients with advanced non-small cell lung cancer, those who received an mRNA vaccine had a median survival of 37.33 months, compared to 20.6 months in 704 unvaccinated patients.
In patients with metastatic melanoma, the difference appeared even more striking. Vaccinated patients (43) have not yet reached median survival, while unvaccinated patients (167) survived a median of 26.67 months, showing a strong survival advantage.
Notably, the benefit was greatest in patients with “cold” tumors—tumors that normally do not respond well to immunotherapy due to low PD-L1 expression. These patients experienced a five-fold improvement in three-year overall survival after receiving a COVID mRNA vaccine.
Consistent Findings Across Variables
The survival benefits were consistent regardless of vaccine manufacturer, number of doses, or treatment timing. This strengthens the conclusion that the vaccine’s immune-activating effects play a central role in improving outcomes.
A Promising New Frontier in Cancer Immunotherapy
“The most exciting part of our work is that it points to the possibility that widely available, low-cost vaccines can dramatically enhance the effectiveness of immunotherapy,” said Dr. Grippin. “mRNA vaccines could help extend these benefits to patients with treatment-resistant cancers.”
To further validate the findings, researchers are designing a multi-center, randomized Phase III clinical trial. This trial will test the role of mRNA COVID vaccines in cancer care. Researchers will determine whether doctors should integrate them into standard treatment protocols for patients receiving immune checkpoint inhibitors.
Transforming a Pandemic Tool into a Cancer-Fighting Ally
This groundbreaking study underscores a new dimension of mRNA vaccine technology—beyond preventing infectious diseases. These vaccines may also reprogram the immune system to fight cancer more effectively“>. If confirmed in clinical trials, the integration of mRNA vaccines into immunotherapy could mark a major leap forward in oncology care.