New Delhi: Common respiratory infections, including Covid-19 and influenza, can awaken dormant breast cancer cells that have spread to the lungs, setting the stage for new metastatic tumours, according to a new study. The findings published in the journal Nature, based on mouse studies as well as meta-analysis of human patients, support research showing increases in death and metastatic lung disease among cancer survivors infected with SARS-CoV-2 the virus that causes Covid. Our findings