Understanding the COVID-19 Incubation Period

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Understanding the COVID-19 Incubation Period

Plushcare Content Team

Written by Plushcare Content Team

Plushcare Content Team

Plushcare Content Team

The PlushCare team is composed of medical doctors, registered nurses, and health experts who enjoy writing about health topics. Our content is reviewed by our team of medical professionals to ensure accuracy.

Mari Carlo Manzana, MD

Reviewed by Mari Carlo Manzana, MD

January 20, 2023 / Read Time 7 minutes

Updated June 26, 2024

NOTE:  Patients who test positive for COVID may qualify for prescription COVID treatment, like Paxlovid or molnupiravir. Learn more about COVID medications.

One crucial question persists in the ever-evolving COVID-19 pandemic: how long after exposure do you get coronavirus? This question has gained notable significance, especially with the rise of new Omicron subvariants such as EG.5 (Eris), FL1.5.1, XBB1.16. This comprehensive guide discusses the intricate details of the COVID incubation period, shedding light on its variability, contagiousness, and associated symptoms.

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How long after being exposed to COVID do symptoms appear?

The incubation period of COVID-19 refers to the span between the moment you contract the virus and the onset of noticeable symptoms. It's a critical window that is crucial in disease transmission and control. Recent insights from the Centers for Disease Control and Prevention (CDC) and various studies have provided valuable data regarding the incubation period's duration. (1)

  • Average incubation period: Studies from 2020 revealed that the average incubation period for COVID-19 was approximately 6.5 days. However, it's essential to note that this can vary based on the viral strain.

  • Delta variant: Historically, the old Delta variant, which is no longer in circulation, was known for its amplified transmissibility and boasted a shorter incubation period, averaging around 4.3 days.

  • Omicron variant: On the other hand, the Omicron variant and its subvariants present  an incubation period ranging from 3 to 4 days, making it even more contagious than its precursors.

In general, the COVID incubation period can vary between three and fourteen days. However, most individuals exposed to the virus begin experiencing symptoms within the first three to four days after exposure.

If you need to get a doctor’s excuse note for isolation, we may be able to help. Learn more about getting a doctor’s note for work or school.

The Silent Spreaders

One alarming aspect of COVID-19 is its capacity for silent transmission. People infected with the virus can unknowingly spread it to others before they exhibit any symptoms. This phenomenon was exacerbated by the Delta variant, leading to viral loads up to 1,260 times higher than those seen in 2020. (9) This increased viral load enhances the virus's ability to spread and heightens the risk of infection.

Although more contagious than Delta, the Omicron variant typically presents a lower viral load. However, the newly emerging EG.5 (Eris) subvariant is causing particular concern, as it is believed to be the most contagious Omicron subvariant to date, responsible for a significant portion of COVID-19 cases at the time of this writing.

For up-to-date information on which COVID subvariants are in circulation, please visit the CDC COVID data tracker website for more information.

How Contagious Is COVID-19?

The contagiousness of COVID-19 is a critical factor in its rapid spread. The research highlights the varying levels of contagiousness among different variants.

  • Delta Variant: Research indicates that the old Delta variant was nearly twice as contagious as earlier COVID-19 variants. (3)

  • Omicron Variant: Omicron takes contagiousness to another level, up to three times more transmissible than Delta. (4) However, the data on the emerging EG.5, FL1.5.1 subvariants’ contagiousness is still under collection.

The Role of R0 in Transmission

R0, or the reproductive number, offers insights into how many individuals can contract the virus from a single infected person. (2) It is location-dependent, with higher population densities associated with increased R0 values. COVID-19 R0 estimates have exhibited significant variations among variants: (3, 4)

  • COVID-19: Estimated R0 of 2

  • Alpha Variant: Estimated R0 of 2-3

  • Delta Variant: Estimated R0 of 5

  • Omicron Variant: Estimated R0 of 8.2

In context, the seasonal flu's R0 hovers around 1.3, while the pre-vaccine era measles had a R0 as high as 18.

This graphic demonstrates how a R0 of 2 spreads from one person to two people. Graphic source: University of Michigan

How Is the Coronavirus Transmitted?

The coronavirus is thought to spread primarily through respiratory droplets and airborne particles released when somebody talks, coughs, or sneezes. These droplets may spread the disease directly from person to person, or the droplets may land on a surface and then be picked up from there.

According to the CDC, fully vaccinated people with breakthrough infections can spread the virus to others. (1) They carry the same amount of virus as those infected and not vaccinated but seem infectious for a shorter period.

Since the coronavirus seems primarily transmitted by people who aren't experiencing symptoms yet, wearing a mask and maintaining social distancing are the best steps to prevent the spread of COVID-19.

What to Do if You Think You Have COVID-19?

Your actions can significantly impact disease transmission if you have a COVID-19 infection. Here's what you should do:

  • Mild to moderate symptoms: Stay home and avoid contact with others for at least five days after symptoms begin. Continue wearing a mask for an additional five days. For treatment options, our doctors may be able to prescribe medication to reduce symptoms of COVID-19. If you think you may have COVID-19, book an appointment with one of our doctors as soon as possible to discuss getting a prescription for Paxlovid or Lagevrio. These medications work best if taken early in the disease course and are recommended to be started within five days of symptom onset. Our doctors can also suggest other treatment options to manage symptoms and prevent spread.

  • Severe symptoms: Seek emergency medical care immediately for symptoms such as chest pain, difficulty breathing, bluish face or lips, inability to stay awake, new confusion, inability to eat or drink anything at all, or seizures. Inform healthcare providers of your COVID-19 suspicions beforehand for appropriate precautions.

  • Testing for clearance: To ensure you are no longer contagious, two negative tests, taken 24 hours apart, are necessary. For most people, after five days, if your symptoms have improved, you may be cleared to return to work or school. However, continue mask usage for an additional five days.

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How Long After Exposure to COVID Are You Contagious?

The only way to be sure you're at low risk for spreading COVID-19 is to have two negative tests 24 hours apart. Once the virus has left your system, you are no longer contagious. According to the CDC, you are most contagious in the early stages of the disease, but you probably remain contagious for 10 days after you start to experience symptoms. (1)

If you develop symptoms of COVID-19, you should isolate yourself for at least five days after symptoms begin and until you have had no fever for at least 24 hours. However, wearing a mask 10 days after symptoms start is still important.

Once you are negative for COVID-19 and are feeling better, you are most likely no longer contagious. It is also generally assumed that after five days if you have not developed symptoms, you can be cleared to return to work or school. Wearing a well-fitting mask for five more days is essential to avoid spreading to others.

What Are the First Symptoms of Coronavirus Disease?

Anyone can experience mild, moderate, or severe symptoms of the coronavirus disease, which may hit all at once rather than gradually. According to the CDC, symptoms may appear 2-14 days after exposure to the virus and may include: (5)

How Long Does it Take to Develop Antibodies After  COVID Infection?

Antibodies are produced due to your body's immune response to an infection. While we do not know yet if antibodies provide long-term immunity to COVID-19, we do know that many people have antibodies in their system after recovering from a COVID-19 infection.

Studies show antibodies take one to three weeks to appear following an infection. This is why it's important to wait long enough after your infection before receiving antibody testing to avoid a false result. Please note that antibodies and antigen testing are different. COVID antigen tests are the primary rapid home tests that are used that help determine if you are currently infected with COVID. Antibody testing is rarely done now but can help determine whether you might have been exposed to COVID in the past or have developed antibodies from a vaccine.

If you believe you are experiencing symptoms or have questions about COVID-19, book an appointment to speak with our board-certified doctors today.

  1. 1

    Book on our free mobile app or website.

    Our doctors operate in all 50 states and same day appointments are available every 15 minutes.

  2. 2

    See a doctor, get treatment and a prescription at your local pharmacy.

  3. 3

    Use your health insurance just like you normally would to see your doctor.

How Can an Online Doctor Help with COVID-19?

Our online doctors can help you determine whether you should get tested for COVID-19 and prescribe antiviral medications if you qualify. Learn more about COVID medications and how our doctors can help you get COVID testing shipped to your home.

Due to the resurgence of COVID, the U.S. Government is offering free at-home COVID tests this fall, starting September 25th 2023. Please visit this website for more information on how to get your free at-home COVID test from the U.S. government.

Our physicians can also advise you on how to manage the physical symptoms of COVID-19 and provide work or school notes for you to isolate. Prescription medications help you better manage your symptoms. In addition, becoming sick with COVID-19 can be highly stressful and emotionally overwhelming. Our doctors are also here to help address any mental health concerns you may have during or after a COVID-19 infection.

Read More About COVID-19


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  1. Centers for Disease Control and Prevention. Clinical Care Information for COVID-19. Accessed on September 14, 2023 at https://www.cdc.gov/coronavirus/2019-ncov/hcp/clinical-care.html

  2. National Library of Medicine. Demystifying R Naught: Understanding What Does it Hide? Accessed on September 26, 2023 at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8117892/

  3. National Library of Medicine. The reproductive number of the Delta variant of SARS-CoV-2 is far higher compared to the ancestral SARS-CoV-2 virus. Accessed on September 27, 2023 at https://pubmed.ncbi.nlm.nih.gov/34369565/

  4. National Library of Medicine. The effective reproductive number of the Omicron variant of SARS-CoV-2 is several times relative to Delta. Accessed on September 27, 2023 at https://pubmed.ncbi.nlm.nih.gov/35262737/

  5. Centers for Disease Control and Prevention. Symptoms of Coronavirus. Accessed on May 20, 2020 at https://www.cdc.gov/coronavirus/2019-ncov/symptoms-testing/symptoms.html

  6. Mayo Clinic. Coronavirus disease 2019 (COVID-19). Accessed on May 20, 2020, at https://www.mayoclinic.org/diseases-conditions/coronavirus/symptoms-causes/syc-20479963

  7. NIH. COVID-19 Treatment Guidelines. Accessed on September 14, 2023  at https://www.covid19treatmentguidelines.nih.gov/overview/clinical-spectrum/ 

  8. World Health Organization - Coronavirus disease (COVID-19): How is it transmitted? Accessed on September 26, 2023 at

  9. National Library of Medicine. Viral infection and transmission in a large, well-traced outbreak caused by the SARS-CoV-2 Delta variant. Accessed on September 27, 2023 at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8786931/

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