mRNA-based COVID-19 Vaccines Improve Immunotherapy Outcomes?

At the 2025 ESMO Congress, interesting data was presented showing that mRNA-based COVID-19 vaccines significantly improve outcomes for cancer patients undergoing immunotherapy. This large retrospective study, conducted by MD Anderson Cancer Center in collaboration with the University of Florida, analyzed clinical data from over 1,000 patients with various types of cancer treated between 2019 and 2023. The study focused on patients receiving immune checkpoint inhibitors, a class of drugs that has revolutionized cancer treatment but still faces challenges with limited response rates in many patients.

The key finding was that patients who received an mRNA COVID-19 vaccine within 100 days before or after starting immunotherapy had double the likelihood of surviving three years compared to those who remained unvaccinated. The vaccine’s benefits were particularly striking in tumors traditionally considered “immunologically cold”, tumors that are typically resistant to immune checkpoint blockade, where vaccinated patients experienced nearly a five-fold improvement in long-term survival. These results suggest that mRNA vaccines can act as a potent immune stimulant, enhancing the immune system’s ability to recognize and attack cancer cells.

Preclinical experimental models supported these clinical observations. The data demonstrated that mRNA vaccination upregulated PD-L1 expression on tumor cells, thereby creating an environment more susceptible to checkpoint inhibitors and leading to an enhanced anti-tumor immune response. Tumors formerly resistant to immunotherapy exhibited slowed growth and increased responsiveness when treated with a combination of mRNA vaccines and checkpoint blockade drugs.

While the findings are based on retrospective analyses, they open exciting prospects for prospective randomized clinical trials to confirm the benefit of integrating mRNA vaccines with immunotherapy regimens in cancer care. Given that mRNA vaccines are widely available, cost-effective, and safe, their use could become a transformative adjunct to immune checkpoint inhibition, potentially expanding the reach of immunotherapy to a broader range of patients, including those with cancers previously unresponsive to existing treatments.

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