Need advice about sick policy

[bright sparks]

"You might have heard that yellow or green mucus is a clear sign that you have an infection, but despite that common misperception, the yellow or green hue isn't due to bacteria.
When you have a cold, your immune system sends white blood cells called neutrophils rushing to the area. These cells contain a greenish-colored enzyme, and in large numbers they can turn the mucus the same color."

From here: http://www.webmd.com/allergies/featu...t-mucus?page=2

Yes the yellow or green mucus is as a result of the enzyme not bacteria, but the high amount present is as a result of infection, bacterial or viral. So it is in fact still true that the presence of yellow or green mucus is a sign of infection because it is only when infection is present that the high levels of enzyme are present. No infection, low levels of enzyme = clear mucus.