A Disconcerting Link: Can Viruses Like the Flu and COVID-19 ‘Wake Up’ Dormant Cancer Cells?

“Dormant cancer cells are like the embers left in an abandoned campfire, and respiratory viruses are like a strong wind that reignites the flames.” This is the stark analogy offered by Dr. James DeGregori, a senior author of a groundbreaking and deeply disconcerting new study. The research, published in the prestigious journal Nature, provides the first experimental evidence for a fear long held by oncologists and cancer survivors: that a common illness like the flu or COVID-19 could potentially awaken sleeping cancer cells, setting the stage for a deadly recurrence.

Part I: The Science Explained

For many cancer survivors, the greatest fear is not the primary tumor they fought, but the possibility that stray cancer cells have spread to other organs. These “disseminated cancer cells” can lie dormant for years, sometimes decades, existing in a kind of suspended animation. The central question for researchers has always been: what, if anything, can wake them up?

To test the role of viral infections, a team of researchers led by scientists at the University of Colorado Cancer Center and the Montefiore Einstein Comprehensive Cancer Center conducted a study in lab mice. The mice had dormant, disseminated cancer cells in their lungs. The researchers then exposed them to common respiratory viruses: influenza and SARS-CoV-2, the virus that causes COVID-19. In both cases, the result was the same. The viral infection triggered a powerful inflammatory response in the lungs, and this inflammation acted like an alarm clock, “awakening” the dormant cancer cells and causing them to stir.

Part II: The Crucial Caveats and Context

While the finding is startling, the study’s authors and independent experts are urging caution. This is a preliminary study in mice, and its findings are not a cause for immediate public panic. The most critical caveat, noted by co-lead author Dr. Julio Aguirre-Ghiso, is that in the study, the awakened cancer cells in the mice went back to sleep once the respiratory infection was resolved.

“That indicates that more than one event, caused by viruses or other sources, might be needed for these metastatic cells to grow and become life-threatening,” Dr. Aguirre-Ghiso said, emphasizing that this research is “step one of future efforts.” Independent oncologists not involved with the study have echoed this, stressing that mouse models do not always translate to human biology and that this is a very early but important clue, not a definitive conclusion.

Part III: The Human Question

This new research in mice does, however, provide a potential mechanistic explanation for some existing human data. Studies from 2020, for example, found that unvaccinated patients with active cancer who contracted COVID-19 had double the risk of dying compared to those who didn’t. The Nature study raises a host of urgent new questions for the millions of cancer survivors worldwide.

Does vaccination against the flu and COVID-19 offer a protective benefit against this inflammatory “awakening”? Should cancer survivors, even those many years in remission, take extra precautions during respiratory virus season? How might this new understanding of the link between inflammation and cancer recurrence change the future of long-term patient care and monitoring? These are now critical questions that researchers must urgently address.

A New and Vital Frontier of Research

This study does not prove that getting the flu will cause a cancer relapse in humans. What it does is open a groundbreaking and vital new frontier of scientific inquiry. For the first time, we have a clear, experimental model showing how the body’s own inflammatory response to a common virus can interact with dormant cancer cells. Understanding this mechanism is the first essential step toward one day developing therapies that can keep those dangerous “embers” from ever being reignited. The takeaway for the public is not fear, but a deeper appreciation for the complex and often unexpected connections between the body’s various systems, and a renewed hope that with each new discovery, we move one step closer to truly conquering cancer.