COVID numbers can be scary, but what do they mean?

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Crunching numbers isn’t for everyone. But when those numbers contain important information — especially critical for everyday life — many have turned to data released by a number of sources announcing everything from new SARS-CoV-2 infections, to hospitalizations, and especially to deaths.

This week started with just under 23,500 souls lost to the virus in New York, with more than 12 percent of that total right here in the Bronx. In terms of new infections and new hospitalizations, the entire state is at lows not seen since before such tracking started.

For the most part, such numbers have been presented on a broader scale, and if drilled down at all, only done to the county level. But a new map offered by the city’s health department goes a bit deeper, taking a look cases and deaths across the city per ZIP code.

The map, shaded in pinks and purples, provides a variety of data from the number of COVID cases per 100,000 to the percentage of positive cases among other results. The area around the 10471 — which represents primarily Riverdale, Fieldston and Spuyten Duyvil, had 770 positive cases as of last week, or about 3,700 per 100,000.

Comparing apples to oranges in new data

Measuring the number of cases per 100,000 is the best way to compare numbers between different areas, said John Orazem, a professor of biostatistics at Lehman College. For example, he said, 100 coronavirus cases out of California is alarming, but the state also has nearly 39 million people. The same number of cases out of Connecticut, with just 3 million residents, would represent a much more significant chunk of the population.

“I can catch three fish in one hour, or I can fish three fish in 10 hours,” Orazem said. “They’re not the same event. So one is suggesting that I’m a more skilled fisherman than the other.”

Measuring this way provides apples-to-apples comparison, by giving all data a “common denominator,” so to speak. That allows public health officials to see how the virus is spreading and killing people, whether it’s in Alaska — where there is a little more than 1 person per square mile — or in crowded New York City, which is more than 26,000 times that.

“So, the cases per 100,000 is meant to give a population-based rate, rather than just numbers that don’t take population density into account,” said Dr. Theresa Madaline, a health care epidemiologist at Montefiore Health Systems. “This is much more meaningful when trying to understand differences in how severely communities are affected by infection and by infection-related deaths. It allows us to compare different geographic areas to understand if there are differences, and then explore why those differences exist.”

The 10463 ZIP code, which encompasses some parts of Spuyten Duyvil as well as larger swaths of Kingsbridge and Kingsbridge Heights, had a lower case rate — about 2,500 cases per 100,000, but a higher number of actual cases, at just over 1,800. The population of 10463, at nearly 73,000 people, is significantly higher than that of 10471, where about 22,000 people live.

What caused the high rate of infection in 10471? That’s hard to say. The data shows only about 25 percent tested positive for the virus, although only about 3,000 tests were administered in 10471, with some 6,000 in 10463.

Higher rates of testing could mean higher positives, Madaline said.

“If sick people can’t get a test, those cases would not be counted,” she said. “So greater access to testing means greater ability to identify people sick with COVID. In addition, there are persons who are asymptomatically infected, or have not yet developed symptoms.”

Testing more people can identify those who have yet to show any symptoms, Madaline added.

Another perspective on coronavirus numbers

Councilman Andrew Cohen isn’t a public health expert, but in his more lay analysis of the numbers, he believes higher income levels and average population age could contribute to higher testing levels.

“I think that 10471, particularly, is an older ZIP code in terms of average age in population,” Cohen said. “Because you’re older, if you get it, you might be more likely to be tested.”

A drive-thru testing site at Lehman opened in March, open at first only to those showing symptoms and meeting specific screening criteria, because of the limited number of tests available. Now testing has expanded, which virtually allows anyone showing symptoms or meeting broader screening criteria, being eligible. 

Riverdale, in particular, also boasts several nursing homes — facilities which have been particularly hard-hit by the coronavirus, reporting thousands of deaths statewide.

Testing might be expanded now, but it hasn’t been through much of the crisis, meaning the full extent of the coronavirus could still be underreported.

“I’m not trying to pass the buck, but, you know, there’s not enough testing,” Cohen said. “And there’s never been enough testing throughout this whole thing. So it’s been very hard to implement policy or even come up with policy.”

While it’s true widespread testing could turn up higher numbers of positive results, Madaline believes it’s also possible people with easy access to testing would be diagnosed and ordered to isolate early, preventing further spread of infection. 

While widespread testing is helpful, new tests are often flawed, Orazem said, and false positive or negative results can falsely skew data.

As the city slowly moves toward reopening, antibody testing sites are slated to expand across the city, focusing on low-income communities and neighborhoods of color, according to Gov. Andrew Cuomo. Antibody tests show who may have already been exposed to the virus, although whether such exposure provides immunity to future infection is unclear.

Cohen would like to see more data become available as the city reopens the city, and that lawmakers at all levels should realize people would want out of their homes after more than two months inside, no matter what the cost in many cases.

“I can make a law, it’s like Prohibition,” Cohen said, referring to the Constitutional amendment banning alcohol a century ago. “I can’t make a law that no one’s going to follow. I think that health policy needs to be informed by the public’s attitude about the crisis.”

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