Coronavirus cases are two to three times more prevalent in some of Houston’s poorest ZIP codes compared with Harris County overall, clustering in several predominantly black neighborhoods where experts worry the virus will be particularly fatal because many residents have underlying medical conditions.

A Houston Chronicle analysis of 4,977 positive COVID-19 tests reported in Harris County through April 20 shows that seven of the 10 ZIP codes with the highest rates were majority black and low-income.

ZIP codes that include some of the city’s primarily African American neighborhoods — from Sunnyside south of Loop 610 to Settegast to the northeast — had double and triple the average per capita rate for Harris County, which reported about 1 case per 1,000 residents.

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The numbers are stark: 77051, which includes Sunnyside, is 85 percent African American. Its median income is $32,000 and nearly 1 in 5 people are unemployed. Three in every 1,000 people there tested positive.

“COVID-19 is a health disparity,” said Peter Hotez, co-director of the Center for Vaccine Development at Texas Children’s Hospital.

The ZIP code analysis is concerning, he said, because it shows that the disease is spreading in low-income neighborhoods where many residents have underlying medical issues, such as diabetes and heart conditions, which increase the risk of becoming seriously ill or dying from the disease.

Experts and public officials warned that although the ZIP code data, the most granular so far released to the public, reveals broad trends, it comes with critical caveats.

Low testing rates and incomplete contact tracing — a public health measure where officials track and monitor an infected person’s contacts to limit the spread of disease — make it virtually impossible to determine the actual spread.

“There may be certain areas where it doesn’t appear to be a hot spot at all, but that’s only reflective of the sense that in many parts of our city, people have not been tested at all,” Mayor Sylvester Turner said recently.

Since the first Texas case cropped up in March, testing has lagged far behind the national average. As of Friday, Texas ranked 49th out of all the states and Washington, D.C., in tests per 100,000 residents. Its testing rate — 776.24 people per 100,000 people — outperformed only Virginia and Kansas.

And even with the limited testing, local authorities have lacked the resources to accomplish a key measure in fighting pandemics — contact tracing, which would help them better track and contain the spread.

From the very beginning, the team of 25 in Harris County’s Office of Science, Surveillance and Technology was overwhelmed, logging 12- to 16-hour days trying to trace the steps of people who tested positive.

More employees were brought on to help, but it still wasn’t enough. Two weeks ago, the county’s public health department decided to stop tracing every single case. Instead, they focused on outbreak clusters and at-risk populations such as health care workers and nursing homes.

In recent weeks, as the racial disparity started to become apparent in death data, Turner and Harris County Judge Lina Hidalgo tried to increase outreach in poorer neighborhoods and ramp up testing.

But Hotez said he’s concerned it might not be enough.

“I’m worried that despite the mayor’s and county judge’s best intentions, people in low-income neighborhoods will get the short end of the stick,” he said. “They’ll have the least access to testing and contact tracing.”

High rate downtown

The data collected by local officials from individual patients is difficult to analyze for demographics because 28 percent list race as “unknown.” That skews any broader analysis. ZIP codes, although not ideal, offer a window into the race and income levels of areas that have high numbers of confirmed cases.

The highest per-capita rate in Harris County was reported in the 77002 ZIP code downtown, but experts cautioned that number likely is high because of positive tests from homeless shelters and the Harris County Jail, where officials have been scrambling to contain an outbreak.

The second-highest rate per 1,000 residents was in the ZIP code that includes Sunnyside, 77051, which sits south of Loop 610 and straddles Texas 288. It had 52 cases — roughly 3.1 per 1,000 residents.

The virus also hit hard in other low-income neighborhoods in 77028 in northeast Houston, which are still recovering from Hurricane Harvey, including Settegast, Trinity Gardens and Houston Gardens. With 2.3 cases per 1,000 residents, the area doubled the countywide average of 1 per 1,000 residents.

Low-income areas are also hit disproportionately because many people who live in these communities work jobs that cannot be done from home at a safe distance from others, such as grocery store workers, experts said.

Dr. David Persse, Houston’s Health Authority, said the racial disparity is due to a combination of factors, including decades of inequality in terms of the quality of medical care.

“One is that there is a higher rate of hypertension and renal failure and diabetes in communities of color,” he said. “Secondarily, communities of color do tend to have to face greater challenges with social disparities of health care.”

Some ZIP codes with above-average rates were near testing stations, including Butler Stadium in southwest Houston, Forest Brook Middle School in the northeast, and Cullen Middle School in South Union. These sites had been accepting all residents seeking testing for about a week by April 20, the date on which the Chronicle’s analysis is based.

Huey German-Wilson, a civic leader in Houston Gardens and Trinity Gardens, doubted proximity to the sites caused the high rates in those neighborhoods, noting that many residents lack internet access to learn about testing sites and others may not have a car to get there.

“I don’t know that we’ve tested enough to get a good gauge of how many people in the community actually have it, even if our numbers are higher,” she said.

Montrose’s predominantly white, middle class and young ZIP code of 77006 had more than double the county’s average with 2.6 cases per 1,000 residents.

Legacy Community Health’s main testing site, one of the first to start testing, is in Montrose. Dr. Vian Nguyen, Legacy’s chief medical officer, said that could be a factor in the high number of cases, but there are too many variables to say anything for certain yet, she said.

One factor could be simply access to testing, experts said.

“If we had widespread testing everywhere, who is to say which ZIP code would light up?” Nguyen said.

That’s why experts say an accurate depiction of overall spread is not possible without more testing.

Public health officials announced last week that Houston and Harris County were doubling their testing capacity for COVID-19 to be able to conduct almost 2,200 tests each day.

But officials acknowledge it’s still not enough.

“Let’s face it, the situation with testing is improving,” Persse said Thursday, “but we have such a long way to go with that that we really do need something significant to change before we’ll have data that we can really rely on and not just use as clues.”

More tracing needed

In normal times, Harris County’s public health department closely tracks each case of a disease — whether it be Zika, measles or COVID-19 — to limit the spread.

When someone tests positive, the department contacts them to figure out where they’ve been and whom they might have infected. A team of people then tirelessly reaches out to everyone the infected person might have been in contact with, asking them to self-quarantine and update the department each day with their health status.

But these aren’t normal times.

Harris County tried its normal tracing tactics with COVID-19 in March, but by the beginning of April, it had become too much for the nine to 10 people tasked with it. The department had to limit its tracing efforts to high-risk populations, such as health care workers, and hoped for the best, said Dr. Dana Beckham, director of the county’s Office of Science, Surveillance and Technology.

Nikki Richnow, who began to feel sick in mid-March, said she never heard from Harris County Public Health after testing positive for the virus and being released from the hospital. The 76-year-old, who volunteers with several local organizations, said she tried to piece together for herself where she might have caught it.

She made a timeline of where she had been and, when she had the energy, called people she’d been in contact with to try to see if any of them had gotten symptoms. But she was working on it intermittently, she said.

“I really, really wanted to know where I got it,” Richnow said. “Now I’m just trying to get well.”

Epidemiologists in other counties have struggled as well.

Fort Bend County — with an estimated population of 800,000 residents — started its COVID-19 response with just four epidemiologists to contact trace. Officials quickly brought in two more with help from the state and have nurses and epidemiology students helping as well.

They’re still a few hundred cases behind, said Kaye Reynolds, deputy director for public health in the county’s health and human services department.

“It was very easy when we had one case,” she said. “It’s a whole other thing when we’re closing in on 900.”

Six other suburban counties surround Harris. Four such as Fort Bend have health departments or districts handling the epidemic. They started with a handful of epidemiologists each. A regional state office is responsible for contact tracing in the other two.

With smaller caseloads, the counties reported being on top of contact tracing so far, with staff working long hours and leaning on others to help. In Montgomery County, they were working six days a week, with the fire marshal’s office pitching in.

Dallas County, the first in the state to enact a strict stay-at-home order, is still tracing every positive case with the help of about 180 people — 150 of them volunteer nurses, physicians and students from medical schools — working long hours through the weekend to track cases, officials said.

Harris County will get relief soon, Beckham said, by hiring an additional 300 employees to help contact trace.

But those employees are being hired in phases, she said, and they won’t be ready to resume extensive contact tracing until the end of May.

“If we had 300 people now, with the number of cases we have now, I think we could reach out to all the cases,” Beckham said.

If Gov. Greg Abbott reopens “massive amounts” of businesses May 4 — as he hinted in a radio interview this week — Harris County won’t have had time to ramp up, which worried some experts.

“Remember how this could go down if we stop social distancing before Houston is ready with widespread testing, contact tracing and syndromic surveillance,” Hotez said. “If we open up the economy too soon, there’s no guarantee that this just dies down when the weather is warm. It might, but the evidence for that is very weak so far.”

Lisa Gray, Matt Dempsey, Jay Root and Jenny Deam contributed to this report.

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