A statewide antibody study estimates that 21% of New York City residents have had the coronavirus, Cuomo says

• A preliminary study surveyed 3,000 New Yorkers across 19 counties in the state and found that 13.9% tested positive for coronavirus antibodies.
• The rate was higher in New York City, where 21.2% of residents had antibodies, indicating they were infected with the coronavirus, Gov. Andrew Cuomo said on Thursday.
• Visit Business Insider's homepage for more stories.

A statewide antibody study found that 21.2% of New York City residents have been infected with the coronavirus, Gov. Andrew Cuomo said on Thursday.

The study tested 3,000 New York residents statewide at grocery and big-box stores for antibodies that indicate whether someone has had the virus. Overall, it found that 13.9% of New York state residents had been infected.

The highest rates of past infections occurred in areas near New York City, which has been the epicenter of the US outbreak. In Long Island, 16.7% tested positive and in Westchester and Rockland counties, 11.7% tested positive. In the rest of the state, just 3.6% tested positive.

The tests were conducted in 40 localities across 19 counties in the state. New York state has 19.4 million residents, meaning that approximately 2.7 million have been infected with COVID-19, per the study. The state recorded just over 15,500 fatalities as of Wednesday, indicating a mortality rate of around 0.5% — far lower than previous estimates.

The study has limitations and Cuomo noted that the results are preliminary. To start, the study relied on a self-selected sample of New Yorkers who went to grocery stores where testing was happening. It's possible that those who thought they had coronavirus and are no longer symptomatic sought out tests.

The full results and methodology have not yet been published in a peer-reviewed journal or released to the public.

"What we found so far is that the statewide number is 13.9% tested positive for having the antibodies," Cuomo said. "They were infected three weeks ago, four weeks ago, five weeks ago, six weeks ago, but they had the virus, they developed the antibodies and they are now recovered."