Explained in plain English

What is the role of a common cold?

A common cold, usually a mild viral infection, can sometimes act as a trigger for more serious underlying conditions, as doctors suspect happened with Penny. While most colds are harmless, in very rare cases, they can inflame the heart muscle or exacerbate existing, undiagnosed heart problems. This doesn't mean every cold is dangerous, but it shows how the body's systems are interconnected.