If you've been exposed to the novel coronavirus [1], your first instinct might be to run out for a test [2], but being tested for COVID-19 too early in the incubation period could deliver a false sense of security and lead you to engage in risky behaviours that could cause others to become infected [3].
"Someone can get a positive [COVID-19] test result as soon as two days after exposure, but we typically ask our patients to wait at least five days for most accurate test results," Nailah Abdulbaaqee [4], MD, a primary-care provider at One Medical in Atlanta, told POPSUGAR.
However, there are no set guidelines for when a person with a known exposure should be tested for COVID-19, and a negative result early on in the two weeks after exposure is no excuse to skip the recommended quarantine. "Testing too early may show you are negative for COVID-19, but this does not mean that you cannot test positive later in the 14-day window," said Kristin Dean, MD, a family medicine physician and medical director at Doctor On Demand [5]. "COVID-19 symptoms [6] may develop up to 14 days after the day of the last exposure to COVID-19."
It's difficult to nail down a timeline for testing because people can respond differently to the virus based on their individual immune system and the type of exposure that occurred, Dr. Dean explained. Additionally, "the virus takes time to replicate after exposure. Sometimes the virus circulating in your body [7] is not sufficient to show up as positive on a COVID-19 test."
She pointed to a study published in the Journal of the American Medical Association, which showed that "people are less likely to show positive test results from a nasal viral PCR swab closer to the exposure [8], becoming more likely to show positive test results from the nasal passages during the first week of symptom onset."
So, What Should You Do If You've Been Exposed to COVID-19?
If you've had close contact with someone who has since tested positive for COVID-19, you should quarantine immediately — meaning, stay at home and avoid contact with anyone outside your household — and talk to your doctor. Your healthcare provider can "determine when is the best time for you to get a test based upon your exposure and personal medical history," Dr. Dean explained.
Stick to that 14-day quarantine, though — even if you're feeling OK. (It's kind of like how you have to finish a round of antibiotics, even if you're feeling better.) "Ending quarantine too early may increase the risk that you will spread the virus unknowingly, during what is called the presymptomatic phase or the period of time before people infected with COVID-19 start to display symptoms," Dr. Dean told POPSUGAR.
If you do start to develop symptoms, you should isolate for at least 10 days [10]. At that point, if your symptoms have improved and you've been without a fever for at least 24 hours, it should be safe to return to your normal routine. That's true, at least, for people who are mildly symptomatic, who should be "infectious no longer than 10 days following symptom onset," Dr. Abdulbaaqee explained. "Those with moderate to severe symptoms may be infectious 20 days following symptom onset."
That said, your doctor is the one who should make the call. Dr. Dean noted that this is especially crucial for people with immune disorders. "Discussing with your doctor to receive an individual recommendation is important," she said.
POPSUGAR aims to give you the most accurate and up-to-date information about the coronavirus, but details and recommendations about this pandemic may have changed since publication. For the latest information on COVID-19, please check out resources from the WHO [11], CDC [12], and local public health departments [13].