The US Center of Disease Control (CDC) has established a frequently asked questions (FAQs) page on their website. Question #4 on the page is a very important question.
How does Covid-19 spread?
The coronavirus spreads from person to person when an infected person coughs or sneezes within six feet of a person. The reason why this virus spreads so quickly is due to this one issue. In other normal viruses, an infected person has to be exhibiting symptoms before spreading to another person. However, a person with Covid-19 with no symptoms can pass the coronavirus with a cough or a sneeze.