Antibody Tests Come Back Positive For 28 Percent In Queens: Data

QUEENS, NY — More than a quarter of Queens residents tested for antibodies showed signs that they were previously infected with the coronavirus that causes COVID-19, according to new city data.

Of the 477,000 people in Queens who have gotten tested for coronavirus antibodies since the start of the pandemic, roughly 28 percent tested positive, according to data released by the Department of Health on Tuesday.

Corona and East Elmhurst residents who sought out the tests were the most likely to test positive, the data shows: Antibody tests came back positive for more than half of Corona residents and nearly 48 percent of East Elmhurst residents who have gotten tested.

Queens had the second-highest rate of positive antibody tests after The Bronx, where a third of those tested for antibodies were positive.

The antibody tests, or serology tests, indicate whether a person may have been exposed to the new coronavirus by measuring their bloodstream for signs that their immune system produced proteins, called antibodies, to fight off the virus.

Mayor Bill de Blasio announced Tuesday that the city's website for coronavirus data would start including the results of antibody tests, but experts warn that such data should be taken with a grain of salt.

Firstly, antibody test results aren't always accurate.

Positive tests results could mean the person has antibodies from an infection with a virus in the same family as the new coronavirus, according to the U.S. Centers for Disease Control and Prevention. The chance of receiving a false negative can be as high as 30 percent, depending on when the test is conducted, according to a Harvard Medical School blog post.

The data also may not accurately reflect the prevalence of antibodies among all Queens residents or New York City residents, because people who have been ill with COVID-19 symptoms or were exposed to the virus may be likelier to seek out antibody testing, the city wrote in a disclaimer about the dataset.

"We will be the first jurisdiction in the nation to present our antibody data this way," de Blasio told reporters. "While there is still much to learn about the science of COVID-19 antibody testing, it is an important element to consider when understanding the epidemiology of COVID."