Virus infections may wake dormant cancer cells, hinting at recurrence risk

New research suggests that while viruses like SARS-CoV-2 do not cause cancer, severe viral infections may flare up dormant cancer cells via inflammatory signals such as IL-6, potentially raising recurrence or metastasis. In mice, dormant breast cancer cells reactivated after COVID-19 or flu infection, and analyses of UK Biobank and US breast cancer data found higher cancer mortality and metastasis among patients who had COVID, especially within a year of infection. The findings are not yet proof of causation, and researchers urge more study, but highlight the importance of preventing severe infections in cancer patients and continuing vaccines and precautions.