How long can you spread your germs once have the symptoms?

Once you start having symptoms of an infectious illness, you can spread your germs to others for anywhere from a few days to a few weeks, depending on the specific illness. For example, with flu, you can spread the virus from 1 day before symptoms start until 5 to 7 days after, whereas with COVID-19, you can spread the virus for anywhere from 2 days before to 10 days after symptoms start, potentially longer for people with severe illness.