Been infected with Omicron? You probably didn’t even notice

Most people infected with Omicron probably didn’t know that they had the virus as it is largely asymptomatic, says new study

The majority of people infected with Omicron, a variant of SARS-CoV-2 that causes COVID-19, probably didn’t know that they had the virus says study from Cedars-Sinai investigators. The findings have been published in JAMA Network Open.

More than one in every two people who were infected with Omicron didn’t know they had it

“More than one in every two people who were infected with Omicron didn’t know they had it,” said Susan Cheng, a corresponding author of the study.

“Awareness will be key for allowing us to move beyond this pandemic.”

As many as 80% of people infected with Omicron experience no symptoms

Previous studies have reported that somewhere between 25-80% of people infected with Omicron experience no symptoms at all.

On the whole, when compared to other SARS-CoV-2 variants, the Omicron variant is considered much less severe.

What are the symptoms of Omicron?

• fatigue
• cough
• headache
• sore throat
• a runny nose

“Our study findings add to evidence that undiagnosed infections can increase transmission of the virus,” adds Sandy Y. Joung, first author of the study.

“A low level of infection awareness has likely contributed to the fast spread of Omicron.”

Omicron or common cold?

In order to understand the effects of COVID-19 and the impact of vaccines, researchers began collecting blood samples from healthcare workers more than two years ago.

Just before the surge of Omicron cases, in autumn of 2021, researchers began to analyse the blood of patients too.

The authors of the study identified 2,479 people who had contributed blood samples just prior to or after the start of the Omicron surge and identified 210 people who likely were infected with the Omicron variant based on newly positive levels of antibodies to SARS-CoV-2 in their blood.

Only 44% of study participants with newly positive SARS-CoV-2 antibodies were aware that they had been infected with Omicron.

The majority (56%) were unaware of any recent COVID-19 infection and of those who had no idea that they had been infected, 10% believed that any symptoms they did have were the result of a common cold or another type of infection.

More diverse studies needed

Authors agree that COVID-19 research requires more studies involving larger numbers of people from diverse ethnicities and communities so that scientists can understand asymptomatic cases and lack of awareness of infection better.

The better we understand our own risks, the better we will be at protecting the health of the public as well as ourselves

“We hope people will read these findings and think, ‘I was just at a gathering where someone tested positive,’ or, ‘I just started to feel a little under the weather. Maybe I should get a quick test.’ The better we understand our own risks, the better we will be at protecting the health of the public as well as ourselves,” concludes Cheng.