Repeat testing now recommended for negative at-home COVID-19 antigen test results

Two significant updates on COVID-19 quarantining and at-home testing have occurred in the last week with potential impact on dental practices and staff.  

First, individuals who perform any at-home COVID-19 antigen test and obtain a negative result should repeat the test in 48 hours to reduce the risk of false negative results, the U.S. Food and Drug Administration advised. COVID-19 antigen tests include the free rapid tests Americans were able to order free of charge from the federal government beginning last spring.  

The FDA’s safety alert advises that individuals who had a close-contact exposure repeat the test following a negative result “whether or not you have COVID-19 symptoms.”  

Importantly for dental practices, unvaccinated dental staff who are testing weekly in continued compliance with California’s vaccinate-or-test mandate are not required by the state mandate to test twice if the first test result is negative, but repeat testing is advised to help prevent spread of the coronavirus unknowingly.  

Second, the Centers for Disease Control and Prevention updated its recommendations for COVID-19 quarantining. Among the changes applying to community settings, quarantining is no longer recommended for individuals who were exposed to COVID-19; instead, those individuals should wear a high-quality mask and get tested for COVID-19 on day 5. 

The CDC states that in the coming weeks it plans to align guidance for specific settings like health care, congregate settings at higher risk of transmission and travel, with the Aug. 11 update. The California Department of Public Health is expected to update its guidance to align with the CDC guidance. 

Retesting to reduce the risk of a false negative 

The FDA’s recommendation for repeat at-home antigen testing was based on the results of a recent study showing that for people infected with the omicron variant, repeat testing after a negative at-home test result increases the chance of an accurate result. Because the antigen tests are less accurate than molecular tests, they are less accurate at detecting the virus early in infection — soon after an individual’s exposure. This is another reason for the FDA’s recommended repeat testing. 

Individuals who are experiencing COVID-19 symptoms or had a close-contact exposure with someone who has COVID-19 should follow the FDA’s repeat testing recommendation if their first at-home antigen test result is negative. The FDA recommends retesting 48 hours after the first negative test. 

Again, unvaccinated dental staff who are testing weekly for COVID-19 in order to report to work can retest to reduce the likelihood of a false negative and unknowing spread of the virus, but they are not required to by California regulation. 

“You do not need to use the same brand of test each time for repeat testing,” the FDA safety advisory states. 

Quarantine no longer recommended for individuals with COVID-19 exposure 

The CDC on Aug. 11 updated its COVID-19 guidance for community settings noting the increased number of tools for reducing the severity of COVID-19 illness and the “significantly less risk of severe illness, hospitalization and death compared to earlier in the pandemic.”  

The most significant updates include: 

  • Individuals who were exposed to COVID-19 do not need to quarantine after exposure, regardless of their vaccination status. They should instead wear a high-quality mask for 10 days and get tested on day 5.  
  • Individuals who test positive for COVID-19 should stay home for at least five days, isolate from others at home and wear a high-quality mask when being around others at home and in public is unavoidable. 

The updated recommendations stress that individuals are most infectious during the first five days of COVID-19 illness. Individuals who test positive for COVID-19 can end their isolation after day 5 if they are fever-free for 24 hours without the use of medication and either never had symptoms or the symptoms are improving. These individuals should continue to wear a high-quality mask through day 10 to protect people who are vulnerable to severe illness. 

More broadly, the updated guidance continues to encourage people to stay up to date with COVID-19 vaccinations to protect against serious illness, hospitalization and death. 

Read the CDC’s news release for all the newest updates on COVID-19 guidance. Once the CDPH updates its state guidance to align, it will be posted on the quarantine and isolation page. 


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