In explaining his cautious optimism about Texas response to the novel coronavirus, Gov. Greg Abbott has often homed in on one cheery-sounding figure: the number of Texans he says have recovered from the virus, which, he boasts, tops that of almost every other state.

The Texas figure, which stands at 28,371, is not an actual tally of the patients no longer experiencing any symptoms, but instead an estimate based on a string of assumptions about the virus longevity. And its difficult to say where Texas really ranks in recoveries, in part because many states, including most of the countrys most populous California, Florida and Pennsylvania do not report the number at all. PolitiFact Texas recently rated Abbotts claim about Texas high ranking half-true.

Some states dont report how many patients have recovered because it simply isnt feasible to track everyone who tested positive for the virus, and there are too many conflicting methods for estimating the count.

And experts say recovery estimates mean little: There is no cure for the new coronavirus, so the number of recoveries best reflects how many people have fallen ill from the virus in a given state the more infections, the more recoveries.

At a press conference Monday, Abbott made a slightly different claim, reporting that with the help of our hospitals, our recovery rate is one of the best in the country. PolitiFact found earlier this month that Texas ranked 16th for recovery rate among states that are reporting recoveries. A spokesman for the governor did not return a request for comment about his source for the claim.

The Centers for Disease Control and Prevention uses clinical criteria to determine when a person is recovered enough to stop self-isolating: either a negative coronavirus test, or improvement in respiratory symptoms and fever over a period of several days.

Texas calculates its recovery total by splitting surviving patients into two groups: an estimated 20% who require hospitalization and an estimated 80% who do not. Texas considers the surviving patients who required hospitalization recovered after 32 days and those who did not require hospitalization recovered after 14 days.

Its working with the tools you have and the knowledge that you have, said Angela Clendenin, an epidemiologist and biostatistician at Texas A&M University School of Public Health. The formulas are sound. They make logical sense. But at the same time, knowing that that's probably the closest we can get to an estimate doesnt always mean its going to be highly accurate.

Many coronavirus patients are never tested because they are asymptomatic or only mildly symptomatic. As many as tens of thousands may not be captured in the states figures, Clendenin said.

And the 14-day recovery assumption may be off base, with some patients reporting long-term health impacts. How to classify the people who experience lasting respiratory issues as a result of the virus?

Other states calculate the number differently or not at all.

It would take a lot of resources to track status on each individual daily until they recovered, said Will Finn, a spokesman for the state of Washington. Because of that, the state is not able to track recoveries, he said.

A spokesperson for Floridas health department said some states and countries measure a case as recovered when a person has had COVID-19 for more than 14 days, while others [rely] upon hospital discharge data neither of which completely capture recovery of the full COVID positive population.

Michigan, for example, includes patients who are alive 30 days after the onset of the illness.

If states are using different criteria, then comparisons are not meaningful, said Shelley Payne, a professor of medical education at the University of Texas at Austin. Tracking the number of new infections and the rate of infections is more important, Payne said.

White House guidelines do not identify recovered patients as a metric states should consider when weighing how fully to reopen, and Abbott hasnt identified it as one either. But the recovery total he boasts about does factor into another important metric for the state: its hospitalization rate.

Abbott has said he uses the hospitalization rate to determine how much to reopen the states economy. The hospitalization rate is calculated using the estimated total of recovered patients.

That rate, which the state reports has been decreasing, is calculated by dividing the number of people who are hospitalized by the number of active cases, a figure arrived at by subtracting the estimated recoveries from total confirmed cases. That means the important metric is based on the states recovery estimate.

Abbott has also boasted that the states estimate of recovered COVID-19 patients has surpassed the number of patients with active COVID-19 cases. But that is only logical, because the number of estimated recovered patients accumulates over time. It would require a spike in cases for the number of active COVID-19 patients to overtake the total number of patients who have recovered over a period of more than two months.

Disclosure: Texas A&M University and the University of Texas at Austin have been financial supporters of The Texas Tribune, a nonprofit, nonpartisan news organization that is funded in part by donations from members, foundations and corporate sponsors. Financial supporters play no role in the Tribune's journalism. Find a complete list of them here.

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Does Texas really rank high in coronavirus recoveries? - The Texas Tribune