homehome Home chatchat Notifications


Comparison between neighboring US counties shows stay-at-home orders reduce coronavirus infections

Two neighboring states show how much of a difference social distancing measures can make.

Mihai Andrei
May 21, 2020 @ 2:22 am

share Share

Iowa did not issue a state-wide stay at home order. The neighboring state of Illinois did. The counties at the border of the two states, where life is similar in many ways, found themselves at divergence. That difference in policy seemed to influence the number of COVID-19 cases.

Image credits: Johannes Krupinski.

The stay-at-home order in Illinois was issued on March 21, while Iowa was among only a handful of states that did not introduce any such order. Rates of COVID-19 had been similar across the Iowa and Illinois counties before March 21 — and for about a week afterward, they remained similar.

But the differences started in late April. After that, cases increased more quickly in Iowa and more slowly in Illinois.

“It’s early descriptive evidence that suggests that more restrictive measures may be related to slower growth of COVID rates,” says George Wehby, a study author and a professor of health management and policy at the University of Iowa.

Researchers merely carried out an observational study — they did not establish a cause-effect relationship, they merely observed the correlation between this policy and the number of COVID-19 cases.

There could be other aspects at play.

The total populations were 462,445 in the Iowa border counties and 272,385 in the Illinois border counties. Population density was higher in the Iowa counties (114.2 people per square mile) than in the Illinois counties (78.2 people per square mile), and this could be an alternative explanation. Other factors (which are not mutually exclusive) might also be at play, researchers add.

“There could be a messaging effect,” Wehby says. “We don’t know how these shelter-in-places are affecting people’s behavior when they’re outside … maybe there is some greater alertness (around) individual behaviors, like staying away from people more than 6 feet, even though you’re outside.”

However, researchers also note that Illinois also had a greater increase in tests per 10,000 residents after the stay-at-home order, suggesting that this isn’t a testing issue. In other words, bordering counties in Illinois really seemed to have fewer cases than the ones in Iowa, which correlates well with a stay-at-home order, but it’s still a correlation-not-causation type of study, so we can’t say for sure whether the stay-at-home order made the difference.

However, the circumstantial evidence seems to lend additional support to the policy making a difference.

A separate analysis published this week in Health Affairs indicates there may have been 10 million more COVID-19 cases in the U.S. by late April without government-imposed shelter-in-place orders.

At the time of this writing, the US, a country with approximately 4.25% of the world’s population, has some 30% of the total COVID-19 cases in the world.

share Share

A Simple Heat Hack Could Revolutionize How We Produce Yogurt

In principle, the method could be deployed tomorrow, researchers say.

Scientists Create a ‘Smart Sponge’ That Knows When to Heal and When to Fight Inflammation

This hydrogel could help millions of people lead a better life.

The Race to the Bottom: Japan Is Set to Start Testing Deep-Sea Mining

There's a big hidden cost to this practice.

Japan Just Smashed the Internet Speed World Record and It's Much Faster Than You Think

Researchers transmitted 127,500 GB every second — over the distance from Chicago to Dallas.

Can You Tell Which Knot Is Strongest? Most People Fail This Surprisingly Tough Challenge

Knots are a test of physical intuition and most of us are failing hard.

Scientists Call for a Global Pause on Creating “Mirror Life” Before It’s Too Late: “The threat we’re talking about is unprecedented”

Creating synthetic lifeforms is almost here, and the consequences could be devastating.

For the First Time Ever We Can See Planets Starting to Form Around a Star

JWST and ALMA peered through a natural opening in the star’s surrounding cloud to catch the action up close.

Low testosterone isn't killing your libido. Sugar is

Small increases in blood sugar can affect sperm and sex, even without diabetes

There might be an anti-aging secret hiding in magic mushrooms

Psilocybin extends cell life, and preserves aging DNA structures.

Not Just Hunters: Wooden Tools Unearth the Sophisticated, Plant-Eating World of Early Humans

What if the Stone Age wasn't really about stone?