After contracting COVID-19, how long will you be positive? There’s no way to know for sure.
The answers vary, according to health officials.
According to the Centers for Disease Control and Prevention, some people who get COVID-19 may have detectable virus for up to three months, but that doesn’t mean they’re contagious.
When it comes to testing, however, PCR tests are more likely to continue to detect virus after infection.
“The PCR test can stay positive for a long time,” Chicago Department of Public Health Commissioner Dr. Allison Arwady previously said.
“These PCR tests are very sensitive,” she added. “They keep picking up dead virus in your nose for sometimes weeks, but you can’t grow that virus in the lab. You can’t spread it, but it can test positive.”
The CDC notes that the tests “are best used early in illness to diagnose COVID-19 and are not cleared by the U.S. Food and Drug Administration to assess duration of infectiousness.”
For those isolating due to COVID infection, there is no testing requirement to end isolation, however, the CDC recommends using a rapid antigen test for those choosing to take one.
Arwady said the advice is likely related to determining whether or not someone has an “active” virus.
“If you wanted to get tested, don’t do PCR. Use a rapid antigen test,” she said. “Why? Because the rapid antigen test is the one that will look to see… do you have a high enough level of COVID that you’re potentially infectious? Now a PCR test, remember, can pick up some kind of traces of the virus for a long time, even if this virus is bad and even if it is not potentially transmissible.
Here’s what else you need to know about COVID testing:
How soon after exposure to COVID could you test positive?
According to the CDC, the incubation period for COVID is between two and 14 days, although the agency’s latest guidelines suggest a five-day quarantine for those who are unboosted but eligible or unvaccinated. Those seeking to get tested after exposure should do so five days after exposure or if they begin to experience symptoms, the CDC recommends.
Those who are boosted and vaccinated, or those who are fully vaccinated and not yet eligible for a booster, do not need to quarantine, but must wear masks for 10 days and also get tested for five days after exposure, unless they show symptoms.
Still, for those who are vaccinated and boosted but still looking to be on the safe side, Arwady said an additional seven-day test could help.
“If you’re having multiple tests at home, you know, the recommendation is to take a test five days later. But if you’ve had one to five and it’s negative and you’re feeling fine, there’s chances are you’re not going to have any more problems there,” she said. “I think if you’re very careful there, if you want to test again, you know, even at seven hours, sometimes people watch three to get an early idea of things. But if you’re going to do it once, do it five and I feel good about it.”
Arwady said testing probably isn’t necessary seven days after exposure for those who are vaccinated and boosted.
“If you’ve been exposed, you’re vaccinated and boosted, I don’t think testing is necessary, frankly, beyond about seven days,” she said. “If you want to be very careful you can do it at 10, but with what we’re seeing I would really consider you clear. If you’re not vaccinated or boosted I certainly have a much bigger concern than that. you could be infected. Certainly, ideally, you would look for that test at five o’clock and I would do it again, you know, at seven o’clock, potentially at ten o’clock.
When is the best time to get tested after exposure?
The CDC says anyone who may have been exposed to someone with COVID should be tested five days after exposure or as soon as symptoms appear.
“If symptoms appear, individuals should immediately self-quarantine until a negative test confirms that the symptoms are not attributable to COVID-19,” the guidelines state.
Former Illinois Department of Public Health Director Dr. Ngozi Ezike has previously said incubation times could change, but those who test early should continue testing even if they test negative.
“We may be learning that the incubation time could be a bit shorter. So maybe you would test at two days,” Ezike said. “Obviously, if you’re symptomatic, you test straight away. But you know, if you want to test at two days, but that negative test… the two days shouldn’t make you think, ‘Oh well, I’m clear,’ you know?You might want to test again and of course symptoms that you can’t ignore – sore throat, headache, all kinds of symptoms – anything new can be a symptom of this new disease.
How Soon Could COVID Symptoms Appear?
According to previous CDC guidelines, symptoms of COVID can appear anywhere from two to 14 days after a person has been exposed to the virus.
Anyone with symptoms should get tested for COVID-19.
Some people may never experience symptoms, although they can still spread the virus.
A person is also considered contagious before symptoms appear.
When are people with COVID most contagious?
The CDC says its guidelines have been updated to reflect growing evidence that suggests transmission of COVID-19 often occurs one to two days before symptoms appear and for two to three days afterward.
“It has to do with the CDC data that really showed that after seven days there was virtually no risk of transmission at this point,” Arwady said. “And in that five to seven day window, you know, there are some that depend on whether people have been vaccinated, underlying conditions, etc., but the risk goes down a lot and the feeling is that in the general population, combined with masking, etc. the risk is really very low.”
For those with no symptoms, CDC guidelines say they are considered contagious at least two days before they test positive.