COVID-19: Incubation Period
Written by Ada’s Medical Knowledge Team
- The COVID-19 incubation period lasts 5 days on average.
- Symptoms of the coronavirus may appear anywhere between 2 to 14 days after exposure
- The incubation period of COVID-19 varies slightly depending on the variant you’ve contracted.
- You are already contagious during the incubation period for COVID-19.
The COVID-19 incubation period is an essential factor in understanding how the transmission of the coronavirus works and why isolation is necessary. In this article, we’ll go into detail about what an incubation period is and why it matters, the differences in the incubation period for the different variants of COVID-19, and some measures you can take to protect yourself and those around you.
What is the incubation period for COVID-19?
To understand the incubation period for COVID-19, it’s crucial to know what an incubation period is. It’s a term used to describe the period between infection with a disease-causing organism, such as the coronavirus, and the appearance of the first symptoms of the disease caused by the organism. It’s important to know that an Incubation period is usually a range, so there may be minor deviations depending on the type of virus and the infected person. 1
How long is the incubation period for COVID-19?
The average COVID-19 incubation period is 5 days. The CDC mentions that symptoms may appear 2 to 14 days after exposure to the virus. For this reason, many countries decided on a quarantine rule of 14 days after possible contact with the coronavirus, as this precaution prevents the further spread of the virus.
The incubation period begins when you come into contact with the virus and get infected. During this period, the coronavirus will invade cells in your body and then replicate. At the end of the incubation period, the first symptoms of COVID-19 will appear. These symptoms may differ from person to person and can vary in severity as well. 2
What does the COVID-19 incubation period depend on?
The length of the incubation period for COVID-19 is determined by a few factors: 3
- The amount of virus particles which have entered the body upon infection. This is also called the infecting dose and may be higher depending on the exposure to SARS-CoV-2 you’ve had.
- How fast the virus can replicate once it has infected someone. This is also known as the replication rate.
- The immune response of the person who has been infected
Do different variants of COVID-19 have different incubation periods?
Studies suggest that the incubation period for COVID-19 depends on which variant you’ve caught. The incubation period for Alpha and Beta was 5 days, whereas the incubation period for the Delta variant was 4.3 days. The incubation period for Omicron is the shortest out of all the variants, as it only takes 3 to 4 days after infection before you start developing symptoms. 4
Can you spread COVID-19 during the incubation period?
It’s possible to spread COVID-19 during incubation, as you’ve already been infected and the virus is already present and replicating in your body.
Studies suggest that it's even more likely to spread the coronavirus during incubation, as you'll not notice symptoms yet. When you are unaware that you are ill, it's unlikely that you'll take extra precautions such as self-isolation and wearing a mask to prevent the spread of the virus.
As the virus that causes COVID-19 is already present in the body during the incubation period, you can quickly spread it through tiny respiratory droplets or aerosol particles that leave your body while you’re speaking, singing, shouting, sneezing, or coughing. When these droplets or particles come into contact with another person’s eyes, nose, or mouth, they’re likely to get infected, as COVID-19 is very transmissible. 5
In order to help protect others and stop the spread of the coronavirus, it's essential to consider the incubation period for COVID-19 and always to be mindful of the fact that even without experiencing symptoms, you could still be infected, especially if you’ve been in contact with someone who experienced signs of a COVID-19 infection.
What can I do to prevent the spread of COVID-19 during the incubation period?
Being aware of the COVID-19 incubation period is vital as you are most infectious at the last stage of this incubation period, namely 48 hours before you first start experiencing symptoms. You remain highly contagious for the first 5 days that you experience symptoms. After that period, you should stay cautious, especially around people at risk for severe illness due to COVID-19. 6 7
To stop the spread of the coronavirus, it’s important to adhere to some preventative measures, such as: 8
- Getting vaccinated and keeping your vaccination up-to-date with the recommended booster shots.
- Adhering to the hygiene guidelines, such as washing your hands thoroughly with water and soap.
- Improving ventilation in indoor spaces or moving activities outside.
- Avoiding contact with people who are experiencing COVID-19 symptoms or who have tested positive.
- Wearing a mask that fits well, covering both nose and mouth. Masks can set a barrier for the particles you breathe, cough, or sneeze out. Respirators such as the N95 mask provide higher protection as they fit closely on the face and filter out particles, including the virus that causes COVID-19.
- Keeping a safe distance from others.
- Being especially vigilant around those who are at risk of severe illness due to COVID-19.
- Getting tested as soon as possible if you’re experiencing symptoms which may indicate an infection with the coronavirus.
How long do you have to isolate if you test positive for COVID-19?
If you've tested positive for COVID-19 during the incubation period or afterward, you can self-isolate to protect others around you from the coronavirus. The CDC has set out some guidelines for those who have been infected. You can still infect others even if you have been vaccinated. Thus, the same guidelines apply.
If you’re experiencing COVID-19 symptoms, you should get tested as soon as possible and quarantine while waiting for your test results. If you test positive for the coronavirus, you should isolate for at least 5 days. If you have been fever-free for 24 hours without medication to reduce your fever, you can end your isolation. However, if your symptoms are not improving, you should continue to isolate until you notice their improvement and you've been fever-free for 24 hours.
Even after you’ve ended isolation, you should still avoid being around people who could get very sick from an infection with COVID-19 and continue to wear a mask around others until at least day 11.
The COVID-19 incubation period is the time between infection with the coronavirus and the onset of symptoms. This period is around 5 days on average, but it can range from 2 to 14 days and can depend on the variant you’ve been infected with. You can infect other people during this time, so it's essential to be aware that this timeframe exists. This way, you can take measures if you think you’ve been exposed to COVID-19.
Q: Can you spread COVID-19 during the incubation period?
A: Yes, you are contagious during the incubation period. Experts even suggest that you are most contagious 48 hours before symptom onset and during the first 5 days that you are experiencing symptoms.
Q: How long is the incubation period for Omicron?
A: The incubation period of COVID-19 varies slightly depending on which variant you’ve been infected with. Omicron has the shortest incubation period, only lasting 3 to 4 days on average.
Q: How long is the incubation period for the Delta variant?
A: The Delta variant has an incubation period slightly shorter than the incubation period for Alpha and Beta but longer than the one for Omicron. On average, you’ll start experiencing symptoms of the Delta variant 4.3 days after exposure to the virus.
Q: Can you test positive for COVID-19 during the incubation period?
A: It’s possible to test positive for COVID-19 during the incubation period, but if your test comes back negative, then it’s recommended to retest when you start experiencing symptoms, as the test result may be inaccurate during the incubation period.