How people without symptoms can spread COVID-19

Published June 26, 2020


The U.S. Centers for Disease Control and Prevention (CDC) has updated masking guidelines since this was written. Get the latest information.

Can you spread COVID-19 if you are asymptomatic?

It is estimated that about 45% of people who contract COVID-19 will have no symptoms. This is one of the biggest challenges regarding the virus. It is clear that asymptomatic people may still have the ability to spread the virus to others.

"It really depends on how high the viral load is in your body. That's what determines how easily you can spread the virus to others," says Nada Fadul, MD, Nebraska Medicine infectious diseases specialist. Viral load refers to the amount of viral particles in the body. 

And this is not dependent on the severity of your symptoms. Even if you are asymptomatic, you can still have a large amount of the virus in your body, similar to someone who has severe symptoms. How well you control the disease varies widely for each person. How healthy you are and the strength of your immune system are important factors, she says.

When is the virus most contagious? 

We are not certain about when the virus is most contagious. We suspect it to be approximately two days before and up to nine days after symptoms start, Dr. Fadul says. That's when the viral load is large enough in your body to become contagious. 

While the virus has an incubation period of up to 14 days, the average time from infection to developing symptoms is five days. 

Our experts recommend you remain quarantined at least five days after your symptoms have stopped, or 10 days from their onset if you have a normal immune system. Dr. Fadul says to choose whichever is the longest amount of time. 

If you're curious, read more about how the virus infects the lungs

Have you been wondering about the chances of reinfection? They're not certain, but the experts think it's unlikely. "There have been a few reported cases of reinfection in South Korea," says Dr. Fadul. "We think that may be because even after the virus has died, the DNA can still remain intact in your body."

Worried you might have the virus? 

If you are experiencing symptoms, visit and follow the prompts be screened or tested for COVID-19. 

Or use our free drive-through clinic located at 50th and G in Omaha. We have partnered with the Douglas County Health Department, UNMC and One World Community Health to make testing as accessible as possible. You don't have to make an appointment, and anyone can get tested, even if you don't have symptoms. Upon arrival, you will be asked to register by scanning a QR code. 

The test is performed by placing a nasal swab through your nostril to the back of your nose, where it is held for 15 seconds. This test can tell if you have active virus in your body. It will not tell you if you've had the virus in the past. That requires an antibody test, which can be ordered by your doctor. 

How to protect yourself

Regardless of if you are experiencing symptoms or have had the virus, the best advice is to continue doing the right thing when you are away from home:

  • Wear a face mask
  • Be diligent about social distancing
  • Don't attend large gatherings 
  • Wash your hands frequently

And remember, what we know about the virus is continually changing as new information becomes available. So stay current on the facts, identify reliable sources of information and be sure to follow the most recent guidelines.