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 isolate, a person should follow isolation guidelines, continue to wear face masks, and avoid close contact with others — even at the end of isolation.
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.
Different variants of the virus appear to have different incubation periods, with Omicron having a
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.
The 2021 study included immunocompromised people who may shed the virus for longer. It is currently not clear whether the result would be the same for people with mild or asymptomatic disease.
It’s also worth noting that infectiousness itself, both in the sense of how much someone will transmit the virus to others and how long they can do so, is
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 shed the virus and spread COVID-19.
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. Visit our coronavirus hub for the most recent information on the COVID-19 pandemic.
When a person develops symptoms or tests positive for COVID-19, isolating from others helps prevent the virus from spreading.
According to the
No symptoms (asymptomatic)
A person may test positive for COVID-19 but never develop any symptoms. Someone with no symptoms can end their isolation period after day 5. Day 0 is the day of the positive test, and day 1 is the following day.
After isolation ends, wear a high-quality mask indoors at home and in public through day 10. If a person
If a person develops symptoms, the clock resets to day 0 and the isolation period restarts.
A person with mild symptoms must isolate until at least day 5. Day 0 is the first day you have symptoms, and the following day is day 1.
After day 5, someone who has had a mild COVID-19 infection can be around other people again if both of the below statements are true:
- 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.
When ending isolation, it is important to wear a high-quality mask at home and in public through day 10. Anyone who is unable to wear a mask, such as young children, should isolate through day 10.
After isolation, people with mild symptoms can consider ending masking sooner if they have 2 negative COVID-19 tests, taken 48 hours apart.
Moderate or severe symptoms
Moderate symptoms of COVID-19 include shortness of breath or difficulty breathing. According to the CDC, a severe case is when a person is hospitalized.
People who have had a moderate or severe COVID-19 infection should isolate through at least day 10. Day 0 is the first day of symptoms, and the 10-day count begins on the following day.
Anyone who has been hospitalized to treat COVID-19 should talk with their doctor before ending isolation.
If you have a moderately or severely compromised immune system
People who are immunocompromised should talk with their doctor before ending isolation. In some cases, a person may need to isolate for 20 days or longer. Testing may be an option to reduce the isolation period.
People who have been in contact with someone with COVID-19
People who believe that they have had exposure to COVID-19 should monitor themselves for symptoms and wear a high-quality mask indoors at home and in public for
Even with a negative test result, it is important to continue these precautions. It can take 10 days for an infection to develop.
If you develop symptoms, test yourself and follow isolation guidelines.
People who have COVID-19 or think that they have COVID-19
People should follow isolation guidelines based on their health status and the severity of their infection. Isolation periods can range from approximately 6 to 11 days or longer.
A person must also continue isolating 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 isolating.
After isolation ends, wearing a high-quality mask is usually recommended during the period when a person may still be able to transmit the virus.
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 weakened immune systems
Anyone who is immunocompromised and may have been exposed to COVID-19 should contact their doctor. A person with a weakened immune system who has had a COVID-19 infection may need to isolate for 20 days or more.
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.
Improving ventilation in the home can help reduce the amount of virus in the air. Consider options such as opening windows, turning on exhaust fans, and using air filters.
If people need to go out
To reduce the risk of spreading the virus, it is best to to isolate according to the guidelines above. Also, avoid visiting vulnerable people during the period after isolation when a person may still be able to transmit the virus.
People who must go out should:
- Wear a face mask:
Well fitting KN95s or N95sprovide good protection. If you do not have access to these, a cloth or surgical mask can offer protection if they are fit well over the mouth and nose. Layering a cloth mask over a surgical mask may offer a better fit and more protection. Worn alone, cloth masks offer the least protection.
- 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 disinfectant wipes.
- Wash the hands frequently.
- Keep the home well ventilated, for example by using air filters and opening windows.
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.
The symptoms of COVID-19 vary greatly from person to person. Some people experience few or no symptoms. However, for others, COVID-19 causes life threatening organ failure.
Most people develop symptoms within
The most common early symptoms include:
- a loss of taste or smell
- shortness of breath
- muscle pain
- stomach problems, such as diarrhea or nausea
- cold-like symptoms, such as a runny nose or congestion
- sore throat
Learn how long it takes COVID-19 symptoms to appear here.
In people with mild cases, these symptoms may seem similar to those caused by allergies, cold, or flu.
In people with more serious cases, the symptoms may steadily get worse. If a person develops severe symptoms such as the following, they should get medical help:
- shortness of breath
- difficulty breathing
- high fever
- chest pain
- inability to urinate
Learn what to do if a person develops COVID-19 symptoms 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 other medical conditions.
For most people, the symptoms of a COVID-19 infection will go away within a few days to a few weeks.
Mild or severe cases can lead to long COVID, according to the
A 2022 review looked at people who had experienced mild to moderate illness with COVID-19. The researchers found that
It is possible for people of all ages to develop long COVID, including children. Researchers are not certain how common long COVID is among children.
One 2022 study found that
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, improving indoor ventilation, and moving indoor activities outdoors can greatly reduce the risk of further spread.
Staying up to date with COVID-19 vaccines and boosters can prevent severe illness and hospitalization.
People should follow isolation guidelines and never assume that an absence of symptoms means an absence of COVID-19.