How Long Are You Contagious With COVID?
Coronaviruses that cause COVID-19 continue to spread around the globe, with the most recent variant being the highly mutated BA.2.86 variant and the most prevalent being the EG5 and XBB variants. Viruses constantly change, leading to new strains or variants. These changes can determine contagiousness, disease severity, and response to treatment.
According to wastewater evaluation by Biobot Analytics, COVID-19 prevalence has increased across the country, starting in mid-July 2023. There is also a slight increase in hospitalizations in both the U.S. and Canada. However, deaths are not increasing, probably because vaccines and previous infections protect against severe disease.
The virus that causes COVID-19 spreads quickly because people who are infected with it can unknowingly spread it during the incubation period, which lasts two to three days before symptoms appear.
Suppose you are exposed to COVID-19 and contract the virus. You are contagious for about ten days after exposure or developing symptoms, with the most contagious period in the first five days.1 People with more severe disease or who are immune suppressed may be contagious for up to a month.
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How COVID-19 Spreads
Coronaviruses, including the COVID-19 virus (SARS-CoV-2), are respiratory viruses that spread when infected people expel droplets or aerosolized particles when coughing, sneezing, exhaling, or talking.
When you breathe out or sneeze on a cool fall day, you can see water vapor from your breath hanging in the air and then eventually falling to the ground. Tiny respiratory droplets exhaled or expelled from your mouth or nose may contain the SARS-CoV-2 viral particles if you are infected.
If a person stands close to you when you expel infected droplets, and the droplets land on their eyes, nose, or mouth, or they inhale them into their lungs, they can become infected. If the infected droplets fall on a surface and a person touches the contaminated surface and then rubs their eyes or nose, they can also become infected.
According to the World Health Organization, droplets can more easily spread among people in confined spaces, especially if poorly ventilated. In poorly ventilated rooms, droplets can hang in the air longer and travel further than a conversational distance.
How Long After COVID Exposure Do You Become Sick?
The incubation period for COVID-19 is between two and 14 days after exposure. During this period, you are infected and can transmit the infection to others, but you have not developed symptoms yet.
An analysis of multiple studies conducted by the Centers for Disease Control (CDC) in 2020 revealed that the average incubation period for COVID-19 was 6.5 days.2
Further research discovered an incubation period of 4.3 days for the Delta variant3 and 3 to 4 days for the Omicron variant.4,5
Some people do not get sick from the COVID-19 virus and, therefore, never develop symptoms.
How Long Does It Take To Test Positive?
Understanding when to take a COVID-19 test and feeling confident in the accuracy of the test results is challenging. For this reason, the U.S. Food and Drug Administration (FDA) advises people to do serial COVID-19 tests.
If you have been exposed to COVID-19 or have symptoms, consider taking a COVID-19 test.
Antigen tests can quickly give you results in the comfort of your home. If the results are positive, the result is accurate and reliable. However, a negative result cannot rule out an infection. To feel confident that you do not have COVID-19, the FDA recommends that people with symptoms do two serial tests with negative results and those without symptoms do three serial tests, each performed 48 hours apart.
If your symptoms are recent in onset or not improving and your COVID-19 test is negative, if possible, wear a mask around people and isolate until you can repeat your test, your symptoms resolve, or you receive another diagnosis. If you have had symptoms for a few days and your at-home COVID-19 test is negative, it is probably reliable.
Polymerase chain reaction tests are more accurate than antigen tests, but it can take up to three days to receive your results.
How Long Are You Contagious With COVID After Testing Positive?
It’s hard to know how long you are contagious with COVID-19 because it is difficult to pinpoint when you are exposed. The contagious period can vary by variant and person. In general, most people are contagious with COVID-19 for about ten days after exposure to the virus.
People with more severe infections or a weakened immune system can remain contagious for up to a month.
Since most people develop symptoms 3-4 days after exposure, they can expect to remain contagious for another 6 to 7 days.
Summary of contagious period for COVID-19:
- Incubation period: People infected with COVID-19 can be contagious 2 to 4 days before their symptoms begin.
- Symptomatic period: Maximal contagiousness is typically 48 hours before testing positive for COVID-19 to about five days after the onset of symptoms.
Screen yourself for COVID-19 if you think you may have been exposed. This can help you determine when you may have been exposed and how long you might be contagious. Take a COVID-19 test after you have symptoms for two to three days. The CDC recommends isolating for at least five days if you test positive for COVID-19 or have symptoms. Use this isolation and exposure calculator to determine how long you should isolate and wear a mask to protect others from COVID-19.
How Long Are You Contagious With COVID Before Symptoms?
The incubation period is two to three days before you develop symptoms but are infected with the virus that causes COVID-19. You can shed the virus and unknowingly spread it to others during this period.
If you have been exposed to COVID-19, take precautions, and wear a mask to protect others until you can test yourself and determine whether you are infected with the virus. The CDC recommends continuing these precautions until day six after your exposure. On day six after your exposure, take a COVID-19 test. If you test negative, continue masking and other precautions through day ten. If you test positive, isolate yourself to protect others from the virus.
Some people carry the virus and can spread it to others without showing any symptoms.
Can Vaccinated People Be Contagious With COVID?
Breakthrough infections can occur in people who are partially or fully vaccinated against the COVID-19 virus. This happens because not everyone’s immune system responds to a vaccine in the same way.
Your immune response to a vaccine wanes over time, and new variants are identified that differ slightly from the virus used to develop the vaccine. Booster vaccines can enhance and prolong vaccine protection. The COVID-19 vaccines for 2023 are updated to protect against newer variants.
The COVID-19 vaccines may not fully protect you against mild disease, but they are very effective in protecting against severe disease.
How Long Are Children Contagious With COVID?
According to the CDC, children are assumed to be contagious for ten days after being exposed to or developing symptoms of COVID-19. This period does not differ from the infectious period for adults.
The incubation period and how long a person is contagious with COVID-19 vary between people and COVID-19 variants.
Do You Need to See a Doctor About COVID Symptoms?
If you have symptoms consistent with COVID-19 and confirm your self-diagnosis with a COVID-19 test, you do not need to see a doctor as long as your symptoms are mild, you stay well-hydrated, and you have no signs of a secondary infection.
You should see a doctor if you are unsure whether you have COVID-19 or have questions or concerns about your symptoms. Telehealth makes it possible to consult with a doctor on the TelegraMD platform while staying isolated and protecting others from infection.
Bottom Line: How Long Should You Isolate With COVID?
If you have symptoms of COVID-19, the CDC recommends that you isolate until you have COVID-19 test results.
If your test results are negative, you can end your isolation.
If your test results are positive and:
- Your symptoms are improving, you can end your isolation after five days if you have been fever-free for 24 hours without using fever-reducing medications such as acetaminophen or ibuprofen.
- If your symptoms are not improving, continue isolation until you are fever-free for 24 hours and your symptoms are improving.
Isolation is an important public health measure to reduce the spread of disease. If you are unsure whether it is safe to end isolation and return to work or school, contact a doctor on the TelegraMD platform. They are available 24 hours a day to answer questions and give advice when you need it.
While we strive to always provide accurate, current, and safe advice in all of our articles and guides, it’s important to stress that they are no substitute for medical advice from a doctor or healthcare provider. You should always consult a practicing professional who can diagnose your specific case. The content we’ve included in this guide is merely meant to be informational and does not constitute medical advice.
1. Cevik, Muge et al. SARS-CoV-2, SARS-CoV, and MERS-CoV viral load dynamics, duration of viral shedding, and infectiousness: a systematic review and meta-analysis. The Lancet Microbe, Volume 2, Issue 1, e13 – e22
Alene M, Yismaw L, Assemie MA, Ketema DB, Gietaneh W, Birhan TY. Serial interval and incubation period of COVID-19: a systematic review and meta-analysis. BMC Infect Dis. Mar 11 2021;21(1):257. doi:10.1186/s12879-021-05950-x
2. Grant R, Charmet T, Schaeffer L, et al. Impact of SARS-CoV-2 Delta variant on incubation, transmission settings and vaccine effectiveness: Results from a nationwide case-control study in France. The Lancet Regional Health – Europe. 2022/02/01/ 2022;13:100278. doi:https://doi.org/10.1016/j.lanepe.2021.100278
3. Jansen L, Tegomoh B, Lange K, et al. Investigation of a SARS-CoV-2 B.1.1.529 (Omicron) Variant Cluster – Nebraska, November-December 2021. MMWR Morb Mortal Wkly Rep. Dec 31 2021;70(5152):1782-1784. doi:10.15585/mmwr.mm705152e3
4. Song JS, Lee J, Kim M, et al. Serial Intervals and Household Transmission of SARS-CoV-2 Omicron Variant, South Korea, 2021. Emerg Infect Dis. Mar 2022;28(3):756-759. doi:10.3201/eid2803.212607