What Is Asymptomatic COVID-19 and Are You Contagious? – Health Essentials

The emergence of COVID-19 and its slow integration into our daily lives has impacted everybody. But that impact hasnt been the same across the board. One reason? The physical experience of being sick with COVID-19 can vary wildly from person to person. Contracting COVID-19 is deadly for some, while others dont get so much as a sniffle. How exactly is that possible?

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Were learning more about COVID-19 every day. And theres so much information out there that it can be hard to keep up. We asked infectious disease specialist Donald Dumford, MD, to bring us up to date on asymptomatic COVID-19. He details the ongoing research on the topic and explains how we can use what we know to navigate our new normal in a smart, safe way.

Simply put, the word asymptomatic means being sick without having symptoms. No fever, no cough, no body aches, no fatigue. Nothing. Your bodys actively battling a disease and in some cases spreading it without you even realizing youre unwell.

Its called being an asymptomatic carrier. Asymptomatic carriage isnt something that happens with all diseases, but it does happen with COVID-19. And it happens quite a bit. Dr. Dumford says its one of the reasons the virus proved impossible to contain and why it transitioned from an isolated outbreak to a global pandemic so quickly.

Dr. Dumford notes that its common to confuse asymptomatic COVID-19 with pre-symptomatic COVID-19, so lets clarify these terms.

As we mentioned, an asymptomatic person goes through the whole course of their illness without developing symptoms. They may never even realize they were sick. The term pre-symptomatic meanwhile, refers to whats called an incubation period. Thats the time between getting infected and showing symptoms of an illness.

All viruses, including COVID-19, have an incubation period. In many cases, its when the virus is most contagious. While they are two different things, being pre-symptomatic and being asymptomatic are both tricky from a disease prevention standpoint because in both cases, a person can pass the virus on to other people without realizing theyre doing it.

Asymptomatic COVID-19 is quite common. Scientists think that at least 20% of all people infected with COVID-19 never have symptoms. Meanwhile, because COVID-19 reinfection is common and many of us have established some immunity to the virus its not unusual to experience both symptomatic and asymptomatic COVID-19 infections over the course of ones life.

At this stage in the pandemic, whether or not having COVID-19 will make you feel sick is, at least partially, a game of chance. But theres a growing body of evidence indicating that some of us are playing with loaded dice.

Studies indicate that children and adolescents may be more likely to have an asymptomatic infection than adults. Research also suggests that a lack of COVID-19 symptoms may sometimes be determined by genetics. That would make sense because we already know that some people are genetically predisposed to developing critical cases of COVID-19 pneumonia. These two branches of COVID-19-related research may one day help us limit the severity of symptoms in people who are prone to severe complications.

Dr. Dumford explains that not having symptoms of COVID-19 doesnt mean you cant infect other people. And the people you infect have the same risk of having symptoms that you did.

In other words, the virus youre passing on isnt different. Whats different is how your body responds.

Given that so many people with COVID show minimal to no symptoms, the possibility of exposure is present virtually every day, Dr. Dumford says. That makes preventive measures all the more important, especially if you or somebody you love is vulnerable to severe complications from COVID.

The U.S. Centers for Disease Control and Prevention (CDC) announced significant changes in COVID-19 isolation guidance on March 1, 2024. Their new policy says that isolation should be determined on the basis of clinical symptoms. That means you can end your isolation as soon as:

You see where this is going: People with asymptomatic COVID-19 infections now arent required to isolate at all. Its still encouraged to wear a well-fitting mask for the five days after coming out of isolation. If you dont have to isolate at all, Dr. Dumford says you should still strongly consider masking in public for five days after youre diagnosed.

Asymptomatic COVID-19 cases have always slipped through the net to a certain extent, even at the height of the pandemic. But in the past, many people had to submit to regular testing to attend work or school. Required testing is much rarer nowadays and many people are no longer able to isolate for five days without facing professional or academic consequences. The pandemic isnt over, but it sometimes feels like it is.

What does all this mean in practical terms?

Theres one other thing to be aware of: While its rare, some people with asymptomatic COVID-19 do go on to develop long COVID. In other words, they develop symptoms days, weeks or months after the virus resolves. And those symptoms continue for months or, in some cases, years.

Approximately 20% of individuals infected with COVID-19 are asymptomatic. That means they dont have any symptoms and may never even know they were sick. Thats a problem from a public health standpoint because the person who had COVID-19 is still contagious and can unknowingly spread the virus to other people. Its also reason #418 that staying up to date on your COVID-19 vaccines is so important.

If you know that you have an asymptomatic case of COVID-19, be sure that you wear a mask and practice social distancing if youre going to be around other people. Isolation guidelines are changing as the virus becomes part of our everyday lives, but your responsibility to protect others from infection isnt.

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What Is Asymptomatic COVID-19 and Are You Contagious? - Health Essentials