Illustration of coronavirus on a molecular level

Understanding how coronavirus spreads is an important part of protecting yourself. Coronavirus transmission can happen in a variety of ways.

Learn more about how COVID spreads and what you can do to protect yourself.

How Does the Coronavirus Spread?

Though novel coronavirus is still very new, we are learning more about the different ways it can spread. There are three primary modes of transmission.

Respiratory Droplets

Respiratory droplets that contain the virus are the primary vehicle for coronavirus spread, according to the CDC.

Respiratory droplets are created by infectious people when they cough, sneeze, sing, shout, talk or even just breathe. If a nearby person inhales these droplets, they can become infected.

If these droplets land on nearby surfaces, they can also become contaminated.

Avoiding Respiratory Transmission

  • Social distancing and avoiding people you don't live with as much as possible is the best way to prevent coronavirus spread.
  • Remaining at least 6 feet apart from others can also significantly reduce your chances of inhaling respiratory droplets.
  • Wearing a mask can also help contain the respiratory droplets you exhale as well as creating a barrier between you and an infected person's respiratory droplets.

Contact Transmission

Another main way coronavirus spreads is by directly touching a person who is infected. You can also get coronavirus by touching a contaminated surface and then touching your mouth, nose or another membrane, which would allow it to enter the body.

Avoiding Contact Transmission

Be sure to:

Airborne Virus Transmission

In October, the CDC officially recognized that coronavirus could spread through airborne transmission. Airborne transmission is when respiratory droplets containing the virus remain suspended in the air for a longer amount of time (hours rather than minutes or seconds). Droplets that remain airborne can also travel over distances greater than 6 feet.

Avoiding Airborne Transmission

There are certain situations that you should avoid to decrease your risk of being infected through airborne transmission:

  • Crowded spaces. Spaces with lots of people and poor ventilation can put you at risk.
  • Inadequate ventilation. Being in closed-off spaces with little ventilation or air movement allows suspended respiratory droplets to build up in the air. If an infectious person is or has recently been in the space, airborne transmission could occur.
  • Taking part in activities that generate excessive respiratory droplets. In addition to the above, certain actions produce more and smaller respiratory droplets than others, increasing the likelihood of airborne transmission in enclosed spaces. These activities include shouting, singing and exercising.

Is the Coronavirus Airborne?

Though we have long known about the coronavirus's ability to spread through respiratory droplets, many have also wondered if the coronavirus is airborne.

After analyzing the evidence currently available, the CDC determined that it's possible for the coronavirus to spread through the air. The difference between airborne and droplet transmission may seem like a technicality, but there are distinct ramifications.

Respiratory droplets aren't all the same. They can be large, even visible to the naked eye. This means that they fall to the ground quickly and are less likely to be inhaled by another person.

In airborne transmission, these droplets are very small, meaning that they are lighter and can remain in the air for extended periods of time. Small droplets can also travel greater distances, moving with air currents. This means that, in certain cases, 6 feet of distance may not be enough to protect yourself.

In a health care setting, taking measures to stop transmission is essential for keeping patients safe. All University of Maryland Medical System hospitals have been isolating patients with or suspected of having coronavirus since the beginning of the pandemic. This practice, which began as a precautionary measure as we learned more about the virus, has since become an important part of keeping our patients safe when they need to go to the hospital.

Does Weather Affect Coronavirus Spread?

While the virus is new and studies are still being conducted, as of November 2020, the relationship between weather and coronavirus spread still isn't fully understood. What we do know is that coronavirus spread can still happen in any kind of weather.

If so, why is there concern about the virus becoming worse in the winter?

Other respiratory viruses, like the common cold or flu, spread more in the winter months. Some believe that viruses can live longer in colder temperatures and lower humidity, but this is still a topic of study and is not currently considered the main contributor to respiratory virus seasonality.

Instead, the main factor seems to be human behavior. When the weather gets cold, we retreat indoors — often with other people in poorly ventilated spaces. This allows highly infectious viruses to spread from person-to-person with ease.

This means that items like humidifiers, while useful for relieving respiratory illness symptoms, will likely have no significant impact on the potential for coronavirus spread this winter. The best way to protect yourself is by using CDC-recommended coronavirus prevention measures.