When is COVID Not Contagious?

Kathryn Lynn Trammel

February 3, 2023


How long you can transmit COVID-19 depends on your age, health status and how well your immune system fights off the virus. You’re most infectious in the first five days after you get sick, but it’s also possible to be contagious for longer.

To prevent infection, you should isolate yourself from others in your home. CDC guidelines recommend isolating for 10 days.

Incubation period

If you get a COVID infection, it can take up to five days before symptoms start showing. This is called the incubation period.

Knowing how long it takes to become infected and see symptoms is essential for public health. It can help determine how long people need to stay home or away from other people.

Several studies have used groups of matched patients who got the disease and a group of never-infected people to figure out how long it takes to become infected with COVID-19. These studies often involve many data-scrubbing and machine-learning algorithms to help weed out signals from noise.


If you have COVID, you may experience various symptoms ranging from mild to severe. Most people recover without needing medical help, though some may have more serious problems that lead to hospitalization.

Fever is one of the most common symptoms. It’s a temperature of over 100.4 F on an oral thermometer or over 100.8 F on a rectal one, and it changes throughout the day.

Infection from COVID-19 spreads by breathing in tiny droplets and particles that contain the virus when an infected person coughs, sneezes, speaks or sings. It also spreads by contacting the eyes, nose or mouth with these tiny droplets and particles splashed or sprayed from infected people.

If you get sick with COVID-19, you’ll need to stay home and isolate yourself until you feel better. This can take up to 10 days.

Viral load

COVID is a coronavirus that can cause severe infections in unvaccinated people or have “breakthrough” infections. Getting vaccinated is the best way to protect against COVID-19.

Symptoms typically occur within a few days of exposure to the virus, and viral loads should peak around two to three days after you begin shedding them, according to Joseph Bailey, MD, a pulmonary and critical care specialist at Northwestern Medicine. However, if you have the original variant of COVID-19, you may be contagious for up to five days after your first contact with it.

Animal studies have shown that repeated exposure to low doses of the virus is just as infectious as one high dose. It’s also important to know that even a person who tests negative after five days of isolating may still be contagious, Mills said. He recommended that you continue isolating until you no longer test positive on a rapid antigen test.


When you are sick, your doctor may order testing to determine if you have COVID. This can help your doctor understand what’s causing your symptoms and whether you need treatment.

Your test results are usually available within three days of collecting your sample. This information can help you stay home and separate yourself from others if you have symptoms.

An antigen test can detect bits of proteins on the surface of the virus called antigens. It can deliver results in 15 to 30 minutes and is most accurate when used within a few days of your first symptoms.

A PCR test can detect the DNA of the virus and is more sensitive than an antigen test. It can also be ordered when an antigen test is negative to confirm a positive result and determine if you are still infected.

After you are sick with COVID, it can take up to two to three weeks for your body to make enough antibodies. These antibodies can help protect you from getting a new infection or severe illness.