Table of ContentsView AllTable of ContentsAverage DurationPositive TestsFirst SymptomsVariantsKids vs. AdultsBy Vaccine StatusProtecting Others
Table of ContentsView All
View All
Table of Contents
Average Duration
Positive Tests
First Symptoms
Variants
Kids vs. Adults
By Vaccine Status
Protecting Others
With COVID-19, you can expect to be contagious for about one to two days before symptoms appear, and stay contagious for up to eight to 10 days after symptoms start.The contagious period might be shorter if you are asymptomatic orvaccinated, and longer if you have severe symptoms or aweakened immune system.
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COVID-19 Contagiousness Over Time
Most people with COVID-19 are no longer contagious 10 days after symptoms start or after a positive test. This timeline generally holds, though transmission risk can vary.
Peak Contagiousness
Once exposed to COVID-19, it takes two to three days to show symptoms. This period is called theincubation period. Even before symptoms start, you can spread the virus through breathing and talking. You’re most contagious when symptoms start and the virus level (viral load) in your body is highest.
Not everyone with COVID-19 peaks at the same time, and a lower viral load doesn’t always mean less virus is being spread. A 2023 study found that people can exhale up to 800 copies of the virus per minute in the first eight days after symptoms start. Therefore, continuing towear masksand following other precautions is important even after isolation ends.
Prolonged Contagiousness
COVID-19 can be contagious for more than 10 days, especially in severe cases or for those who are immunocompromised. The CDC notes that people with severe illness (such as whenpneumoniaorsevere respiratory distressis involved) or compromised immune systems may shed the virus for longer.
Studies show that severe infections can result in high viral loads, extending contagiousness to over a month in rare cases. Immunocompromised individuals, such as those on chemotherapy or with advanced HIV, may shed the virus for a median of four weeks, according to a 2023 study in the journalPathophysiology.
How Long Will You Test Positive for COVID?
After testing positive for COVID-19, you mightcontinue to test positivefor up to 90 days, especially with NAAT tests. Reinfections can happen within this period, making it difficult to determine if a positive test is from a new infection.
If 10 days pass and you are still testing positive for COVID, you should still consider yourself contagious. It’s best to continue isolating until you have been fever-free for at least 24 hours.
How Long Does COVID Immunity Last?
What Are the First Signs of COVID?
The first sign of a COVID infection is often a low-grade fever, defined as a body temperature between 100.4°F and 101.5°F. Not everyone infected with COVID will have a fever, though.
The first signs of COVID could also include:
About 44% of COVID-19 infections in the U.S. are asymptomatic.This is a major public health challenge since the virus can still spread without symptoms.
Asymptomatic cases are generally less severe and have a lower viral load. Typically, asymptomatic individuals shed the virus for about six days, while symptomatic individuals shed it for an average of nine days.
Am I Still Contagious After 10 Days if I Have a Cough?Most otherwise healthy people are no longer contagious 10 days after their symptoms begin.People with a weakened immune system or severe illness may remain contagious for four weeks or more.
Am I Still Contagious After 10 Days if I Have a Cough?
Most otherwise healthy people are no longer contagious 10 days after their symptoms begin.People with a weakened immune system or severe illness may remain contagious for four weeks or more.
Which COVID Variant Is Most Contagious?
Compared to previous strains, newer COVID variants spread more easily and can make people sicker because they can dodge immune system detection.
As the virus mutates, the mutations that survive best are the ones that escape immune detection, making it harder for our bodies to fight off the virus.
As of May 2024, the most dominant variants were a group of variants called “FLiRT,” which include the Omicron subvariants KP.2 and JN.1.
FLiRT variants are considered more contagious than previous ones. They have an increased ability to infect cells and evade the immune system. This is true even for people who have been previously infected or vaccinated.
Are Kids More Contagious Than Adults?
According to a study in theJournal of Allergy and Clinical Immunology,which monitored 1,394 families from 2020 to 2021,children were actually more likely to transmit COVID-19 than other members of their households.
Does Vaccination Reduce Contagion?
People who have received an updated vaccine have a reduced risk of infecting someone else with COVID-19. However, your contagiousness likely depends on a few factors, including how recently you got a booster, and whether you are immunocompromised.
A 2022 study published inJAMA Network Openwas one of several that showed that fully vaccinated people have a shorter duration of infectious viral shedding—as well as a lower risk of transmitting it to others—than either partially vaccinated or unvaccinated people.
The study, which involved high-risk healthcare workers, hospital patients, and caregivers, found that the duration of contagiousness was roughly 10 days for unvaccinated people and eight days for partially vaccinated people—but only four days for fully vaccinated people.
How to Protect Other People
Health experts generally agree that COVID-19 is here to stay and that continued vigilance is needed as new variants and outbreaks emerge.
To protect yourself and others from this highly contagious virus, the CDC recommends the following preventive measures:
How COVID-19 Is Treated
Summary
The contagiousness of COVID-19 can vary. Generally, contagiousness starts one to two days before symptoms begin, and lasts for eight to ten days after symptom onset. People with mild or asymptomatic illness are usually no longer contagious after 10 days. People with moderate to severe illness or who are moderately to severely immunocompromised may remain contagious for four weeks or more after symptoms begin.
15 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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