11/11/2025
The Surprising, Newly-Discovered COVID Vaccine Side Effect
There's a potentially new incentive to get vaccinated and boosted: A University of Florida study in the journal Nature revealed a link between mRNA-based COVID vaccines and surviving cancer.
Researchers examined clinical outcomes for more than 1,000 late-stage melanoma and lung cancer patients who were treated with a type of immunotherapy called immune checkpoint inhibitors. Immune checkpoint inhibitors block a protein that tumor cells create to deactivate immune cells, essentially training patients' immune systems to kill cancer cells.
Patients in the study who got either the Moderna or Pfizer mRNA COVID-19 vaccines within 100 days of beginning immunotherapy were more than twice as likely to survive after three years as patients who didn't receive either jab. Further, patients whose tumors don't respond well to immunotherapy were five times more likely to survive past three years if they had a Pfizer or Moderna mRNA COVID vaccine than patients who didn't get vaccinated. Finally, these results held up even when researchers factored in variables like co-morbidities, disease severity and patients' other medical conditions.
Uh, this is pretty huge, but what does it all actually mean in practice? We asked infectious disease experts and oncology researchers.
"This study opens an intriguing possibility: that modern mRNA vaccines—originally designed to prevent viral infections—may enhance the efficacy of cancer immunotherapy, particularly immune checkpoint blockade," Dr. Zihai Li, MD., Ph.D., founding director of Pelotonia Institute for Immuno-Oncology, Klotz Memorial Chair in Cancer Research and professor at the Ohio State University College of Medicine, explains. "In other words, receiving an mRNA vaccine around the time of immunotherapy could 'prime' the immune system to respond more vigorously against cancer."
That surely sounds promising, but Dr. Li points out something significant in the research that's important to keep in mind.
"The findings are most directly relevant to solid tumors such as lung cancer and melanoma, where they have the most data, and that checkpoint blockade is already a mainstay of treatment," he says. "However, much remains to be learned ... In patients, the only mRNA vaccines they looked at were mRNA vaccines against SARS-CoV2. If confirmed, these findings could reshape how we integrate vaccines and immunotherapy, transforming preventive vaccines into therapeutic allies against cancer."
With all that said, please keep in mind that this isn't a cure.
"Current clinical guidelines, including those from the American Society of Clinical Oncology (ASCO), do not recognize direct anti-cancer effects as a rationale for COVID-19 vaccination in cancer patients,"
Dr. Steven Goldberg, MD, MBA, chief medical officer at HealthTrackRx, advises. "The primary benefit of COVID-19 vaccination in this population is the prevention of COVID-19 and its complications."
