ZIP Code Maps Showing Virus Impact May Be Misleading

The state Department of Health is working to correct data that overstate the number of cases in ZIP codes that contain hospitals and other places where positive tests are confirmed or patients treated.

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Florida is providing very detailed information to the public on the impact of the coronavirus pandemic -- who is affected and where they live or died -- perhaps more than any state in the nation.

But one of the most precise bits of information -- the number of positive cases found in each ZIP code -- can be misleading.

"Ideally," the state department of Health says on its website, the ZIP code is "a representation of a COVID-19 positive person's residence. However, there are instances where the zip code may reflect the hospital where a person/case was admitted or tested. We are working to review these cases and appropriate them to the correct residential information."

Take a look at the state's COVID-19 data and surveillance dashboard, click at the bottom on the "Cases by zip code" tab, and you can get an idea of where the most cases are reported.

ZIP codes with more than 100 cases appear red; those with more than 200, a deeper burgundy.

But a close look at the reddest ZIP codes in Miami-Dade reveals they share more than just a high number of cases -- almost all of them also include hospitals where COVID testing is taking place or being reported.

"The testing site is there, so obviously you’re going to see more reports from that area," said Dr. Jack Michel, owner of Larkin Community Hospitals, which has tested more than 3,200 people at its Palm Springs campus in Hialeah. "That doesn’t necessarily mean that the people that live in that area, it’s not a hot spot in any way."

The Hialeah hospital's ZIP code, 33012, shows 236 positive cases Wednesday evening; Hialeah as a city has 638 cases, according to the latest DOH data.

But Michel said the Hialeah numbers could be higher for at least two reasons: residents were among the first to have access to testing, after he opened a site at his Hialeah hospital on March 20; and he believes his hospital's ZIP code -- instead of the patients' -- is being reported to some degree in the data the state is relying on.

"I realize how that can be misconceived," Michel said "If anything, I think Hialeah has got a lot of testing done, probably more testing done than a lot of areas currently under testing."

As of Tuesday, Larkin's Hialeah site has done 3,242 tests and returned 530 positives. Those who say they have symptoms can be tested there. Some without insurance or who are ineligible for Medicaid or Medicare pay a $150 lab fee. Michel said those with coverage are also tested, but without charge or co-pays.

The state Department of Health has not yet responded to a request for comment on how valid its ZIP code numbers are, since they readily note they can be inflated by hospitals and test centers in those zones.

Michel said he thinks the discrepancies could be significant. "I think the majority of it has to do with this. You look at any hospital that’s doing testing, you’re going to find those ZIP codes to light up. And it just happens to be the fact there’s a hospital there and that’s where testing is done."

Indeed, the five ZIP codes in Miami-Dade with the most cases also include Jackson South Medical Center, Baptist's South Miami Hospital, Mount Sinai Medical Center in Miami Beach, Larkin's Palm Springs in Hialeah and the Jackson/University of Miami hospital complex in Miami.

But there are also some areas without hospitals that report more than 100 cases: South Beach; North Miami/Biscayne Park; Miami Lakes/Hialeah Gardens; and the Brownsville/Allapattah neighborhoods of Miami.

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