The Centers for Disease Control and Prevention released findings from a study that examined the rate of Americans that have been infected with COVID-19, finding that 57.7% of U.S. residents display signs of previous infection.

That number increased in children and adolescents, with 75.2% of the age group displaying signs of a previous COVID-19 infection.

The study examined blood samples submitted for clinical testing for the presence of anti-nucleocapsid (anti-N) antibodies, which appear after a COVID-19 infection but are not produced post-vaccination. 

The repeating study was conducted each month between September 2021 and February 2022. Between December 2021 and February 2022, the number of U.S. residents displaying signs of a previous COVID-19 infection increased from 33.5% to 57.7%, which coincided with the spread of the Omicron variant throughout the United States.

According to the study, previous infection with COVID-19 "should not be interpreted as protection from future infection. Vaccination remains the safest strategy for preventing complications from SARS-CoV-2 infection, including hospitalization among children and adults."