MANHATTAN (CN) — Sampled randomly in supermarkets across the city, more than 1 in 5 New Yorkers tested positive for antibodies of the novel coronavirus, suggesting far greater exposure than was previously thought.
New York Governor Andrew Cuomo announced the findings Thursday at a press conference in Albany, unveiling preliminary antibody data gathered with a finger-prick study on 3,000 people in grocery and big-box stores across the state this week.
A whopping 21.2% of New York City shoppers were found to carry antibodies to Covid-19. The number 16.7% on Long Island, and statewide the number falls to 13.9% or 2.7 million people.
“This basically quantifies what we have been seeing anecdotally,” Cuomo said
With the official fatality count at about 15,500, the study says the death rate for the virus in New York is around 0.5%.
Telling the public to take that figure with a grain of salt, however, Cuomo emphasized that the state’s official death toll does not include presumed Covid-19 deaths, such as those who died at home or those who were never tested. New York City, for example, reported 10,290 confirmed Covid-19 deaths and 5,121 “probable” Covid-19 deaths as of Thursday.
Denis Nash, an epidemiologist at the City University of New York’s School of Public Health and Health Policy, said in an email Thursday it might be too soon to estimate the state’s Covid-19 fatality rate. Many of the current cases are still sick or in the hospital, he noted, and therefore there may be additional deaths among those estimated 2.7 million currently infected.
Even a seemingly small jump in the reported fatality rate — from 0.5% to 0.7% — is more than 3,000 people, Nash pointed out.
New York City Mayor Bill de Blasio emphasized the importance of both antibody and diagnostic testing at a separate press conference Thursday.
“The coronavirus is alive and well and living in New York City,” he said, later adding, “the more testing we get, the more truth we will find … all roads lead to testing. The more you have, the more you can trace each person’s reality.”
Those with antibodies are presumed to have some immunity from Covid-19, which could ultimately help leaders determine which social-distancing guidelines they should lift. Such serology testing, as it’s called, can also help predict the total number of infections in the United States, which is expected to be a dramatic undercount due to testing shortages.
The New York study has some significant caveats: One of the more glaring issues is that people at home were excluded. By conducting the test at stores, the state considered people who left their homes representative of the rest of the state — an assumption that fails to consider the reality of households that designated one healthy or less vulnerable member to buy groceries and run errands.
It’s also possible people flocked in line to get a test because they thought they had been exposed or have had Covid-19 in recent months, which could bias the sample. More data on the study’s methods was not immediately available Thursday, and the Department of Health did not immediately respond to follow-up questions.
“Yes, design loses value if people know about it,” Bethany Hedt-Gauthier, a global health and social medicine professor at Harvard, wrote on Twitter in response to discussions of the testing.
Jonah Bruno, a spokesman for the state Department of Health, said the study was done in grocery stores to find enough adults for an adequate, representative sample.
“Store locations were selected to maximize the chances that a racially/ethnically diverse population was reached,” Bruno said in an email Thursday. “Where possible, we worked with chains such as Wegmans and Price Chopper to simplify the store recruitment process. The objective was to recruit between 100-200 patrons per store. The sampling procedure selected was chosen to greatly expedite the survey, which is believed to be the largest conducted to date.”