A recent study published Tuesday in the journal JAMA Internal Medicine found that most Americans are still susceptible to COVID-19.

According to the study, researchers studied the blood samples of 177,919 Americans across the nation, D.C., and Puerto Rico between July 27 and Sept. 24. They found that fewer than 10% of the people had detectable COVID antibodies.

“In this U.S. nationwide seroprevalence cross-sectional study, we found that as of September 2020, most persons in the US did not have detectable SARS-CoV-2 antibodies, and seroprevalence estimates varied widely by jurisdiction,” the authors concluded. “Continued biweekly testing of sera collected by commercial laboratories will allow for assessment of the changing epidemiology of SARS-CoV-2 in the U.S. in the coming months. Our results reinforce the need for continued public health preventive measures, including the use of face masks and social distancing, to limit the spread of SARS-CoV-2 in the U.S.”