How long does COVID last? Incubation period, isolation timing and more

As more people begin testing positive for COVID once again, how long might symptoms last? Or if you have no symptoms, how long should you isolate?

The timeline for COVID is dependent on a number of factors.

Currently, multiple mutations of the omicron COVID-19 variant are making their way through the United States. The Illinois Department of Public Health warned late last month that COVID cases are on the rise in the state.

For those who contract the virus, here are some timing guidelines to note:

COVID timing

The guidelines for isolating have not changed since May, according to the Centers for Disease Control and Prevention.

Here are the protocols listed by the agency:

Regardless of vaccination status, you should isolate from others when you have COVID-19, the CDC reports. You should also isolate if you are sick and suspect that you have COVID-19 but do not yet have test results. 

If you test positive for COVID-19, you should stay home for at least five days and isolate from others in your home. The CDC notes that people are "likely most infectious during these first five days."

When you have COVID-19, isolation is counted in days, as follows:

If you had no symptoms:

• Day 0 is the day you were tested (not the day you received your positive test result)
• Day 1 is the first full day following the day you were tested
• If you develop symptoms within 10 days of when you were tested, the clock restarts at day 0 on the day of symptom onset

If you had symptoms:

• Day 0 of isolation is the day of symptom onset, regardless of when you tested positive
• Day 1 is the first full day after the day your symptoms started

If you had no symptoms, you can end your isolation after day five, but for those who experience symptoms, that line might be different, the CDC notes.

Those who have mild symptoms can end isolation after day five if they are fever-free for 24 hours, without using fever-reducing medication, but those with more moderate or severe illnesses will need to wait until day 10.

Those who have mild symptoms that are not improving should also wait until those symptoms are improving and they are fever-free for 24 hours.

Those with more severe illness may also want to consult with their doctor before ending isolation and could need a viral test to end their isolation period.

Despite ending isolation, those who test positive should continue to avoid people and mask through at least day 11, according to the CDC guidelines.

Testing timing

Those who have symptoms are urged to take a COVID test as soon as possible, though officials continue to caution that a negative at-home test may not be as reliable as a positive one.

"If your antigen test is negative, take another antigen test after 48 hours or take a PCR test as soon as you can," the CDC states.

Those who don't have symptoms but may have been exposed should wait five days after exposure to take a test, according to the CDC guidance.

While many Americans may have unused tests in their homes, it's important to check the expiration dates, experts say.

The Food and Drug Administration has extended the expiration dates of many popular at-home test products, which means some such kits may still be safe to use, CNBC reports. You can check expiration dates for each brand using a page on the FDA's website.

Symptom timing

First, in order to know symptom timing, you'll need to know the symptoms of COVID.

Dr. Andrew Pekosz, a virologist at Johns Hopkins University, told TODAY.com that there was no data on symptoms associated with BA.2.86 infections because the case numbers are just too small.

EG.5, meanwhile, also known as “Eris,” is likely more transmissible than the previously-dominant XBB.1.16 variant, according to experts at Yale Medicine. According to Yale officials, EG.5 has a spike protein mutation that allows it to evade some immunity acquired from infection or vaccination, but officials do not believe it causes more-severe illness in most cases.

It typically causes symptoms in a patient’s upper-respiratory tract, including runny nose, sore throat, and other cold-like symptoms. Fever can occur, as can changes in taste and smell.

In patients with compromised immune systems, or those 65 and older, the virus can still cause issues in lower parts of the respiratory tract, which can lead more severe illness.

If you do suspect you've contracted COVID, here are some symptoms you might experience:

• Cough
• Sore throat
• Runny nose
• Sneezing
• Fatigue
• Headache
• Muscle aches
• Altered sense of smell

As for timing, symptoms can last for several days, but in some cases, even longer.

"Some people who have been infected with the virus that causes COVID-19 can experience long-term effects from their infection, known as Long COVID or Post-COVID Conditions (PCC)," according to the CDC.

Such symptoms can last for weeks and possibly even years.