April was a cruel month.


In Missouri, COVID-19 killed 315 people in 30 days.


Nationwide, the death toll was 59,013.


And worldwide, 190,855 deaths were recorded from coronavirus infections in April.


That is almost 11 every day in the state, 2,000 every day nationwide and 6,400 per day worldwide.


Now, Missouri is preparing to reopen. Gov. Mike Parson says we are ready, with a lower daily count of new cases, adequate hospital space and supplies and limits on how much gathering people can do.


State Health Director Randall Williams says we are ready. There is expanded testing capacity with an ability to flood tests into an area to "box in" new outbreaks and send teams to do contact tracing.


Most important, they said, Missouri is flattening the curve.


That means that the spread of the coronavirus is slowing and while not over, the danger is less.


HOW IT’S MEASURED


The Tribune has tracked the daily increase in cases and deaths in Missouri, the nation and the world since the first case was reported in the state on March 7. Late last week, after providing epidemiologists with the data on the number of new cases every day for the month, the Tribune asked them to define flattening the curve and what data they considered most important to measure for that definition.


The curve, meaning infections tracked on a graph, is bending. The number of new cases per day has been declining in the state and steady nationally, they said. That means that people who are infected are then spreading it to one other person or less.


Christelle Ilboudo, an infectious disease specialist and assistant professor in the University of Missouri School of Medicine, said she looks at several models but advises that they are “not necessarily all very precise.”


For Ilboudo, a stable number of new cases over time is one measure and so is new hospitalizations. Those numbers have shown improvement, she said, but that’s not enough to declare the pandemic ended.


“Some of us were never exposed, and suddenly, when we all go out and about, we increase that risk of being exposed and getting sick,” Ilboudo said. “The point is that it is not as fast that it is over.”


David McKinsey, an infectious disease specialist with HCA Midwest Health Research Medical Center in Kansas City, said he watches new cases reported, new hospitalizations and deaths from the disease.


Hospitalizations are his key data point to determine where things stand.


“With hospitalizations, we know that a certain percent will be ill enough to require hospitalization and the criteria are standardized,” McKinsey said. “Looking at trends in hospitalizations provides the most meaningful information.”


And Elvin Geng, director of the Center for Dissemination and Implementation Science in the Institute for Public Health at Washington University, said he, too, looks at new hospitalizations as the most reliable figure.


Hospitalizations in the St. Louis metro region, which has two-thirds of all known infections in Missouri, have stopped growing, but they have remained stubbornly resistant to a decline, Geng said. That shows a large number of new infections well into April, long after the regional stay-at-home order took effect on March 22.


“Shelter in place is essentially our nuclear option,” Geng said. “What this shows is our nuclear option wasn't that nuclear.”


Unfortunately, the data on hospitalizations in Missouri has not been as good as the state’s tally of new cases. The Missouri Hospital Association compiles the data and changed both the format of its reports, and the definitions for some data, twice in April.


There were 896 hospitalized COVID-19 patients in the state on Saturday, including nine at University of Missouri Hospital in Columbia and two at Boone Hospital Center. That was 117 more than the week beginning on Sunday, but the number has been as low as 655 and as high as 891 previously during the week.


The definition of how those cases are counted changed on April 25, so data from before that date is not comparable to current numbers.


Another example of how the data being reported has changed involves ventilators. The number of mechanical ventilators available in the state has been part of it since the first report. But only in the past week have the reports shown how many COVID-19 patients are on ventilators. There were 137 on Friday.


The state reported that 27.1 percent of ICU beds in the state were available Friday, the lowest share since reporting started. That definition has not changed.


An increase in the number of cases reported, McKinsey said, could mean continuing spread or it could be related to the increasing availability of testing.


Deaths, he said, are “a lagging indicator.” That is because the number of deaths on any given day doesn’t indicate when a person became infected.


“It would definitely be encouraging to see a downward trend in deaths,” McKinsey said. “In some cases this could be explained by improvements in medical care, but a declining death rate is correlated with an overall decline in disease.”


WHAT’S NEXT


Any individual in Missouri who wants a COVID-19 test must show symptoms but for certain classes of individuals, including first responders and hospitalized patients, the test will be given even if there is no known contact with a case confirmed by testing.


The state has also been doing mass testing and community surveillance testing. At the Triumph Foods plant in St. Joseph, where 259 cases were discovered, more of the 2,300 tests administered have to be processed. Many of those people had no symptoms.


The tests have a limited utility in determining whether there is new spread of the disease because some patients will test positive well past the time they are contagious, Ilboudo said.


“The question we haven’t answered is, just because I find genetic material, is it capable of leaving my body and making somebody else sick?” Ilboudo said.


The key to controlling an epidemic is to keep the ratio of new cases to existing cases below one, Geng said. Anything above one and sooner or later there will be disease spread that can overwhelm health systems as was seen first in Wuhan, then Italy and later New York.


“We need to have our antenna up,” he said. “One antenna is a very strong testing program. That depends on being able to detect those pockets and that means testing has to be incredibly widely available and immediately accessible.”


For the month of April, the average number of newly reported infections in Missouri was 208 per day, with the highest weekly average during the second week of April, at 248. But this past week, with 592 new infections reported Friday and Saturday, the weekly average rose to 266 per day after trending much lower.


Part of it was a mass testing program in Buchanan County, but most of it was a continued high number of new cases in the St. Louis metro area.


Tests tell only so much, Ilboudo noted. Some people have positive results for 30 or 40 days after they have recovered from the disease, she said.


McKinsey, author of two articles on the 1918 flu pandemic, said the daily totals show the disease continues to spread. It is too early to relax social-distancing measures such as the stay-at-home order, he said.


The flu in 1918 started at an Army camp in Kansas in the spring, subsided in the summer and came roaring back that fall, after infected soldiers took it to France. That epidemic was very responsive to social distancing measures and communities that ended them too early in the fall paid a price with a third wave of infection and death.


The key issue with the coronavirus is that it is easy to acquire an infection and it spreads rapidly.


“There is still a large percentage of the population that are susceptible, and we don’t have a vaccine, and this is a highly contagious virus,” McKinsey said. “It doesn't take much to start a new outbreak.”


The speed of reopening will determine whether the pandemic reignites with exponential growth, which would put Missouri back on the wrong side of the curve, Geng said.


“Unless there is a strong seasonal affect, and there could be, but if there is not, it is hard for me to see us getting through the next six to 12 months without things getting worse and requiring us to intensify again,” Geng said. “We will have to be judicious and smart about how we go about it.”


The first wave of infection taught health care providers how to ramp up for any new outbreaks, Ilboudo said. It has also shown the importance of identifying and rapidly tracing contacts of infected people to limit the spread of contagion.


She, too, called for a cautious reopening.


“Things are not going back to the way they used to be because we don't know how long we will have the wave of this virus,” Ilboudo said. “We may not ever go back to way things were before, but we can at least start slowly getting back to some normalcy.”


rkeller@columbiatribune.com


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