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Thursday, June 1, 2023 | 
Coronavirus U.S. & World Health

False negative COVID-19 tests could be more likely in those who have immunity

Those who have been vaccinated or previously infected with COVID could be more likely to produce a false negative test

By Ashley Nash
SHARE False negative COVID-19 tests could be more likely in those who have immunity
An illustration of the coronavirus.

Illustration by Michelle Budge

The Centers for Disease Control and Prevention has linked COVID-19 immunity to false positives when taking a rapid COVID-19 test, according to an Oregon ABC News site.

False negatives: Sometimes, when taking a rapid antigen test, a false negative can appear during the first day or two of symptoms. This is because the immune system is doing exactly what it should do, ABC reported.

  • If an individual has been vaccinated or has been previously infected, when that individual is infected again with COVID-19, the body keeps the case and symptoms mild enough that they aren’t detected by a rapid test.
  • “Their antibodies and their white blood cells are fighting that virus, and even though it’s present enough to make you sick, it’s not present enough that it’s making enough of the protein that’s detected in your nose to make the test positive,” Dr. Ann Loeffler, a deputy health officer in Oregon, told ABC.

The bottom line, the CDC states that if you have previous immunity, you’re more likely to produce a false negative on a rapid test, per ABC.

Rapid test accuracy: Harvard Health Publishing from Harvard Medical School states that rapid antigen tests produce more false negatives than any other COVID-19 test.

Related

  • Harvard recommends that individuals experiencing COVID-19 symptoms either take several rapid tests, or a PCR test to determine whether or not they are infected.

Are at-home tests accurate? At-home COVID-19 tests are an affordable and accessible way to determine if one is infected with COVID-19.

  • A study published in the Journal of the American Medical Association reported that at-home COVID-19 tests have a sensitivity of about 64%, compared to a PCR test that has 84% sensitivity.
  • Dr. Jeffrey Klausner, an infectious disease specialist at the University of Southern California, recommends that individuals repeat at-home tests a day or two after developing symptoms to ensure they don’t have COVID-19, according to NBC Los Angeles.
  • However, at-home and other rapid tests aren’t useless. They show you whether or not you have enough of the virus to be contagious.
  • “When somebody is negative on an antigen test, it means they’re not contagious,” Dr. Amesh Adalja of Johns Hopkins University told NBC.