The novel coronavirus, which causes the disease COVID-19, is highly contagious. Even people who do not have any symptoms can transmit the virus. How long a person is contagious with the coronavirus varies, and scientists do not have a precise answer that applies to every case.
When in doubt as to how long they should quarantine, a person should follow quarantine guidelines, continue to wear face masks, and avoid close contact with others — even at the end of quarantine.
This article will explain how long people may be contagious with COVID-19 depending on their individual circumstances. It will also provide information on what a person can do to protect those around them and explain the symptoms and recovery times associated with COVID-19.
Experts believe that the time from exposure to symptom onset, also known as the incubation period, is 2–14 days. However, symptoms typically appear within 4–5 days of exposure.
The median length of time that participants continued to shed the virus was 8 days after first developing symptoms. At 15.2 days, the odds of continuing to shed the virus were less than 5%.
These results suggest that shedding may occur for longer than 2 weeks in some people with COVID-19. However, the study only included people who were receiving treatment in a hospital for moderate to severe COVID-19. It is currently not clear whether the result would be the same for people with mild or asymptomatic disease.
When are people most contagious?
For this reason, people should ensure that they isolate immediately if they think that they may have come into contact with the virus or if they have developed symptoms.
What if there are no symptoms?
In people without symptoms, determining contagiousness is difficult, as many people without symptoms may never know that they have COVID-19.
If a person has no symptoms, they are asymptomatic. If a person does not have symptoms but later develops them, they are pre-symptomatic before they experience the symptoms.
A 2020 study found that both asymptomatic people and pre-symptomatic people can and do spread the virus.
Researchers looked at 31 people hospitalized for other reasons who tested positive for COVID-19 but did not have any symptoms. Of these participants, 22 eventually developed symptoms, while nine never did.
Overall, the length of time that the study participants shed potentially contagious virus particles was in the range of 5–16 days.
All data and statistics are based on publicly available data at the time of publication. Some information may be out of date.
- It has been 10 days since they first developed symptoms.
- They have not had a fever for 24 hours and have not used fever-reducing medications.
- Their other symptoms of COVID-19 are improving.
If a person is only experiencing a loss of taste and smell as a lingering symptom, they do not need to continue isolating.
It is important to note that this recommendation is for people who have had symptoms. Also, it does not apply to people who have had severe COVID-19 or those who have a severely weakened immune system. Other recommendations exist for these groups.
- People who have been in contact with someone with COVID-19: People who believe that they have had exposure to COVID-19 should quarantine at home, away from others outside of the household, for 14 days since they last saw that person.
- People who have COVID-19 or think that they have COVID-19: People should stay away from others for 10 days after symptoms first appear. They must also continue quarantining for at least 24 hours after their last fever. If a person still has a fever when they do not take fever medication, they must continue quarantining.
- People who have had a severe case of COVID-19: People who have had severe symptoms of COVID-19 may need to isolate for up to 20 days after they first noticed them. A person should talk with a doctor for more information.
- People with weak immune systems: People with weak immune systems may need testing to understand when they can be around other people. A person should talk with a doctor for more information.
Learn more about the transmission of SARS-CoV-2 here.
Protecting others in the same household
People who live with others should try to stay away from them as much as possible. They could quarantine in a basement or an isolated spare bedroom, if the space is available.
Avoid the main areas of the house, especially when other people are there.
If people need to go out
To reduce the risk of spreading the virus to vulnerable people, it is best to avoid them entirely and to quarantine per the guidelines above.
People who must go out should:
- Wear a face mask: People should try to
wear two face masks. Healthcare professionals should wear N95 masks.
- Maintain as much distance from others as possible: People should leave a minimum of 6 feet (2 meters) between each other.
- Not make physical contact with others: It can be difficult to live with less physical contact. However, people can contact loved ones using electronic devices and work from home if possible.
- Frequently wash the hands: People should wash their hands often and for at least
20 seconds. Use soap and water or hand sanitizer if soap and water are not available.
Learn about different types of face mask to protect against COVID-19 here.
One of the challenges of caring for a person with COVID-19 is that by the time they have symptoms, they might have been contagious for a few days.
Nevertheless, a caregiver can reduce their exposure by taking the following precautions:
- Wear a face mask at all times while around the sick person, and ask the sick person to do the same.
- Try caring for the person through a door. Leave food outside the door, then walk away before they open the door.
- Help the person quarantine in an isolated part of the house.
- Use video chat to stay connected, rather than talking in person.
- Wipe down all surfaces the person touches using bleach or alcohol wipes.
- Wash the hands frequently.
It may also be helpful to prepare for the possibility of illness.
Try placing a large grocery order, structuring a home quarantine area, and stocking up on medical supplies.
Learn how to wash the hands properly here.
The length of time it takes a person to recover from COVID-19 depends on many factors, including whether or not they develop symptoms, how severe any symptoms are, and whether or not they have any underlying medical conditions.
The study did not take into account the exact severity of the disease or any underlying health conditions. It did not include those with severe symptoms.
They ranged from around 5 days for younger, healthier people to 2 or more weeks for older, less healthy people. The median length of stay was 11 days.
Some people were discharged to nursing homes or rehabilitation facilities. Although this may indicate that they had not fully recovered from COVID-19, it may also be that this is where they were originally living.
A small 2021 study included participants of all ages and symptom severities. The researchers found that
The results suggest that people over the age of 65 years may be more likely to experience long COVID.
However, it is possible for people of all ages to have long COVID, including children.
Learn about the symptoms of long COVID here.
People with COVID-19 tend to be most contagious just before and just after the appearance of symptoms. However, some people may develop no symptoms at all. These people can still transmit SARS-CoV-2.
It is important to reduce the transmission of SARS-CoV-2 and the spread of COVID-19. Taking precautions such as wearing a face mask and practicing physical distancing can greatly reduce the risk of further spread.
People should follow quarantine guidelines and never assume that an absence of symptoms means an absence of COVID-19.