Vivica A. Fox Tests Negative for COVID-19 After Potential False Positive
Here's what you should know about testing accuracy.
Vivica A. Fox is officially COVID-free. Fox opted out of Sunday's Emmy Awards red carpet coverage due to a positive coronavirus (COVID-19) test, but she announced on Tuesday, September 22nd, that she has since tested negative for the virus. In her Instagram post, she hinted that her false-positive test may be due to the fact that it was self-administered.
"On Friday I took a self administered Covid-19 test and as many of you are aware, it came back positive," she wrote in the image of the post, which was captioned, "GM Dawlings! I DONT HAVE COVID-19 I TESTED NEGATIVE!"
Fox continued, "Two days ago I took another Covid test, this one administered by a medical professional, and I am thrilled to announce that last night my results came back NEGATIVE!"
The American Horror Story actor and overall icon updated her fans on how she's doing now. "I am feeling great and I want to thank everyone for their show of love and support."
Both Fox and her red carpet co-host Giuliana Rancic had to miss the 2020 Emmys at the last minute due to positive tests. Rancic released a video message explaining that she, her husband Bill, and her son were all recovering from coronavirus after testing positive.
Fox isn't alone in receiving an incorrect coronavirus test result.
In March, Alyssa Milano said she took two separate COVID-19 tests and a finger-prick antibody test after experiencing symptoms. According to Milano, all three tests reported the virus was not detected. However, in August, she said she was tested for antibodies via a blood test, and antibodies were detected—meaning she did, most likely, have coronavirus earlier this year.
According to an April report by MIT Medical, there are two different types of accuracy when it comes to laboratory testing: "sensitivity" and "specificity."
Sensitivity is the "test's ability to tell us when an individual is infected," whereas specificity is the test's "ability to tell us when an individual is not infected," the report reads. "A test that is very sensitive is less likely to give false-negative results, and a test that is highly specific is less likely to give false positives."
Because the test used to diagnose COVID-19 is a molecular test, it works by detecting genetic material from SARS-CoV-2, "the virus that causes COVID-19." This genetic material can be found in the nose and upper throat of an infected person, which is why the nasal swab testing method is used.
This test, when done correctly, is incredibly accurate, MIT Medical explains, but because it's not equally sensitive, an incorrectly administered test can result in a false negative, like in Milano's case.
A false positive result, though uncommon in COVID-19 testing as UC Health reports, can be caused by cross-contamination at the test site. However, false-positive antibody tests are much more common.
“That’s been one of the limitations [of antibody testing],” Dani Zander, MD, chief of Pathology and Laboratory Medicine at UC Health said. “If you live in a low prevalence area like we do, a lot of the positive antibody test results are false-positive results.” Many times, false-positive results can be caused by picking up antibodies from other types of coronaviruses.
Getting tested by a professional, and getting tested several times is the best way to ensure you either have or don't have COVID-19. For the most part, coronavirus test results are accurate when done correctly. But, if your gut is telling you otherwise, get another test and talk to your doctor.