When it comes to COVID-19, there are still many questions about how the virus spreads and what role the HVAC system can play in its transmission. According to the Centers for Disease Control (CDC), the virus that causes COVID-19 is thought to spread mainly from person to person through respiratory droplets that are produced, for example, when an infected person coughs, sneezes, talks, sings, etc. These droplets can land in the mouths or noses of people who are nearby or possibly be inhaled into the lungs, which is way more likely when people are in close contact with one another (within about 6 feet).