How Long Does COVID-19 Stay in Your System?

How long COVID-19 stays in your system can vary, but most people who get COVID are no longer contagious after 10 days. Those with severe COVID may remain infectious beyond 10 days and need to take additional precautions.

However, there are people in whom COVID has been known to persist for months rather than weeks. In fact, it’s possible for COVID to remain in the body more than a year. While cases like these are rare, there is increasing evidence that the virus may persist in other tissues for longer than previously thought and possibly contribute to the development of long COVID.

How Long Is COVID-19 Contagious?

As a general rule, most people with mild to moderate COVID are no longer contagious 10 days after symptoms first appear. However, for people with severe symptoms or weakened immune systems, the virus can stay in the system for longer periods of time.

When you get COVID, you are contagious because your body is continuously shedding infectious particles (called viral shedding). Until viral shedding fully ceases, there is a chance you can infect others. The shedding can persist whether you have symptoms or not and even after you no longer test positive for COVID.

However, as time passes, the potential for infection dramatically decreases as there are generally too few viral particles for an infection to be viable.

How Long Does COVID Last if You’re Vaccinated?

Vaccination status can affect how long you are contagious with COVID, as well as how long the virus stays in your system. Ongoing research suggests that those who are vaccinated against COVID may be able to clear the virus from their bodies faster than their unvaccinated counterparts.

According to a 2022 study published in Emerging Infectious Diseases, vaccinated people with mild or asymptomatic COVID experience shedding six to nine days after being diagnosed or developing symptoms. While shedding can persist well after this time, any viruses shed after the first 10 days are considered non-viable due to their low numbers.

The same may not be true for people who remain unvaccinated against COVID-19. A 2022 study published in PLoS Pathology reported that unvaccinated people continue to experience viable shedding an average of seven and a half days compared to six days for those who were vaccinated.

While a 15% difference may seem incidental, as new variants of COVID-19 continue to emerge, the length of time people are contagious may change and the difference in shedding times between vaccinated and unvaccinated people may widen.

How Long Should You Stay Home Once You Test Positive for COVID?

In March 2024, the Centers for Disease Control and Prevention (CDC) revised its guidance on the isolation of people with diagnosed or suspected COVID.

According to the CDC, if you test positive for COVID or have symptoms of a respiratory viral infection:

• Isolate at home until you’ve been fever-free for 24 hours (without taking fever-reducing medication) AND your symptoms are mild and improving.
• Take additional precautions for five days following isolation, such as wearing a well-fitting mask, keeping a distance from others, and washing your hands often.

COVID Can Stay in the Body Long After Infection

Research shows, that for some people, the COVID-19 virus can remain in the body for more than a year after infection.

One such case presented at the 2022 European Congress of Clinical Microbiology & Infectious Diseases described an incident in which an immunocompromised person tested positive for 505 days until the time of their death.

A similar case was identified in London in which positive COVID test results were returned for more than a year in another immunocompromised individual.

While this shouldn’t suggest that being immunocompromised inherently prevents you from clearing the virus, it may lengthen the time that COVID remains in the body.

Of seven other immunocompromised people monitored by the King’s College researcher, the average duration of viable viral shedding was 73 days. Each had different reasons for their weakened immune state, including organ transplantation, HIV, cancer, and medical treatments used to treat other illnesses.

Similar cases were identified in Spain and China where viral shedding persisted for 189 days and 169 days, respectively.

Viral Persistence and Long COVID

There is also evidence that COVID may persist in other tissues outside of the respiratory tract even when COVID tests show no sign of the virus.

According to researchers at Stanford University who monitored 113 individuals with mild to moderate COVID, nearly half (49.2%) had evidence of viral shedding in their stool. Even after the nasal swab tests came back negative, 12.7% continued to shed the virus in their stools for the next four months. By month seven, 3.8% were still shedding the virus.

Another study published in Science Translational Medicine in 2024 found that the virus could replicate in tissues for up to two years after infection.

In theory, this might explain why certain people develop long COVID in which symptoms persist for more than 12 weeks even when tests show no evidence of the virus. In fact, the vast majority of COVID long haulers test negative for the virus.

Summary

The amount of time that COVID stays in the body varies from person to person. That’s one reason why it’s important that you take steps to protect others if you are ill or think that you were in contact with someone who might have been.

If you have COVID, you can help curb the spread of the virus by taking the necessary precautions. The best way to reduce your risk of infection is to stay up to date with COVID-19 vaccines.