More than half of adults infected with the omicron variant in a small regional study did not know that they were infected and potentially contagious, researchers say. The lack of awareness likely played a role in the rapid transmission of infections during the omicron wave, the authors note.

Investigators analyzed the records from 210 adult employees and patients of an academic medical center in Los Angeles County, CA. Participants were enrolled in another study that tested for evidence of the SARS-CoV-2 omicron variant using blood samples. 

Fully 56% reported that they were unaware of any recent omicron variant infection, investigators found. What’s more, only 10% of these participants reported experiencing any recent symptoms or signs of a common cold or other type of infection. 

Studies have estimated that 25% to 48% of community cases of COVID-19 are asymptomatic, and up to 80% in highly exposed populations, the authors reported. The omicron variant, which now accounts for almost 90% of all infections, has been found to cause less severe infections than prior variants. 

“Our study findings add to evidence that undiagnosed infections can increase transmission of the virus,” said researcher Sandy Joung, MHDS, of Cedars-Sinai Medical Center. “A low level of infection awareness has likely contributed to the fast spread of omicron.”

The authors call for greater availability and use of rapid antigen testing to raise individuals’ awareness of infection and potentially reduce rates of person-to-person transmission of the omicron variant.

The study was published in JAMA Network Open.

Related articles:

CDC: Seniors receive 80% protection against severe omicron illness with fourth vaccine dose

With omicron spreading fast, officials implore nursing home providers to push COVID-19 booster shots