Is your Florida ZIP code a COVID-19 hot spot? Why it’s hard to know for sure

Looking at the Florida Department of Health’s map of confirmed COVID-19 cases broken down by ZIP code, it would be easy to assume that 33028 is a hot spot for the disease.

That ZIP code represents a part of western Broward County almost entirely within the city of Pembroke Pines, plus slivers of Davie and Southwest Ranches. As of Sunday afternoon, the area had 435 confirmed cases of the novel coronavirus, more than any other ZIP code in Florida.

But it would be wrong to say definitively that 33028 is the ZIP code with the most residents diagnosed with COVID-19. That’s because, according to state health officials, some cases counted toward a given ZIP code are initially attributed to where a person was tested, not where they live.

In other words, some of the 435 cases in the 33028 ZIP code may be explained by the fact that there is a COVID-19 testing site located there: a drive-thru site at C.B. Smith Park in Pembroke Pines that opened March 20.

Positive cases “may be originally attributed to that site when first reported,” said Alberto Moscoso, a spokesman for the Florida Department of Health. “It is important to note that this may add to the total in the ZIP code for C.B. Smith Park,” Moscoso said.

That data is “provisional,” a department spokesperson said Sunday, and is used “until confirmed residency information becomes available.” But nothing on the state’s COVID-19 dashboard indicates how many cases in a given ZIP code are attributed to something other than one’s home address.

Moscoso said the availability of testing for residents near a testing site could be contributing to higher case totals in that area. But according to the state’s city-level data, Pembroke Pines has just 41 residents who are confirmed positive for COVID-19 — far fewer than the 435 cases listed in 33028, which represents just one section of the city.

Conflicting guidance

The health department first added ZIP code-level data to its COVID-19 dashboard April 3. In a question and answer page on its website, the department says the ZIP code data is “ideally a representation of a COVID-19 positive person’s residence,” but that “there are instances where the ZIP code may reflect the hospital where a person/case was admitted or tested.”

On a different question and answer page, the department says cases are “counted in a ZIP code based on residential or mailing address, or by healthcare provider or lab address if other addresses are missing.”

The website says officials are “working to review these cases and appropriate them to the correct residential information.” On April 6, the Miami Herald asked the Florida Department of Health if it could provide a version of the ZIP code data that’s based only on home addresses — stripping out any data based on the addresses of testing sites, hospitals or labs.

So far, the department has not provided any such data.

More refined data in other parts of the United States has helped the public and health experts understand how the novel coronavirus has spread and which communities have been hit the hardest. In New York, data released by health officials April 1 helped the New York Times conclude that people in low-income neighborhoods may be the most vulnerable.

Even the city-level coronavirus data in Florida, which has been available in daily reports since mid-March, has drawn skepticism.

That data, state officials say, is “based on the cities of residence for cases in Florida residents based on the patient’s ZIP code.” They add this caveat: “Note that city is not always received as part of the initial notification and may be missing while the case is being investigated.”

The Florida Department of Health didn’t immediately clarify whether the city-level data, like the ZIP code-level data, could also be muddled by hospital or testing locations.

Miami Beach questioned accuracy

In Miami Beach, part of which appears as a hot spot on the state’s dashboard, Mayor Dan Gelber incorporated the citywide numbers into his video addresses to residents after state officials first began reporting positive COVID-19 cases there.

But that only lasted about a week after Gelber said there was a discrepancy between the state’s numbers and those gathered by Miami-Dade County’s state-affiliated health department. Without a clear indication of how many residents in Miami Beach had tested positive, Gelber decided to stop announcing the numbers.

“Just so you know, we are no longer reporting our city data to you, as it has also become apparent that a good deal of the reported data isn’t reliable or even reflective of the extent of the infections in our community,” he said.

Gelber added: “With such limited testing and reporting failures, I think the wisest course is for you to assume everyone you come upon may be infected and act accordingly to minimize the risk to you and your loved ones.”

In the absence of widespread testing or reliable data on hard-hit areas, Miami-Dade County officials recently rolled out a countywide effort using pinprick blood tests to learn how much of the population has already been infected without knowing it — and to possibly identify hot spots.

Although the blood tests have limited accuracy and can’t detect the novel coronavirus in its earliest stages, they can detect antibodies that tell researchers if someone had the virus weeks or even months ago. A team of county officials and University of Miami health researchers has started testing 750 residents a week from representative population samples across Miami-Dade.

Miami Herald staff writer David Smiley contributed to this report.

This story was originally published April 12, 2020 at 5:18 PM.