Respiratory illnesses such as Covid and the flu can awaken dormant cancer cells in the body and cause them to spread, scientists have warned. Researchers found when mice were exposed to Covid or influenza, dormant cancer cells woke up and spread rapidly.

Common respiratory infections like COVID and the flu could awaken dormant breast cancer cells in the lungs and lead to metastatic disease. These findings were based on mice infected with COVID and influenza that experienced massive awakening of dormant cancer cells.