Study Reveals True Reasons for COVID-19 Flare-ups

The first comprehensive research of state-by-state re-openings shows ad hoc policies worsen spread of COVID

MIT IDE
MIT IDE
Sep 8, 2020 · 4 min read
Image for post
Image for post
Credit: Ketut Subiyanto

As summer vacations end in Europe and in the United States, and students try to return to college campuses and primary schools, fresh waves of COVID infections are causing renewed restrictions after loosening in the spring and summer. What’s going on?

Why is COVID-19 still flaring up more than six months after its initial surge in the U.S.? Why haven’t shelter-in-place, shut-downs, and social distancing effectively stopped the spread of the pandemic, and why are restrictions being re-imposed?

The answers to many of these vexing public health questions can be found in a new study that shows how uncoordinated opening, closing, and reopening of states and counties, is making the COVID problem worse in the U.S. Using methods from their previous work, published in the Proceedings of the National Academy of Sciences, MIT PhD student Michael Zhao and Sinan Aral, Director of the MIT Initiative on the Digital Economy and author of the upcoming book The Hype Machine, have released the first comprehensive study of the impact of state-by-state re-openings on the COVID pandemic, spanning January to July, 2020 — with surprising and troubling results.

After studying combined data on the mobility of over 22 million mobile devices, daily data on state-level closure and reopening policies and social media connections among 220 million Facebook users, the team found that reimposing local social distancing or shelter-in-place orders after reopening may be far less effective than policy makers would hope.

This analysis demonstrates that travel spillovers are not only systematic and predictable, but also large and meaningful.

Put simply, the findings highlight the urgent need to coordinate COVID-19 re-openings across regions and the risks created by ad hoc local shutdowns and re-openings.

Arizona was one of the first states to open businesses, but in late June, bars, gyms, movie theaters, and water parks were shut down for 30 days as the state became one of the virus’s new hot spots. One month after dine-in restaurants, bars, and gyms were allowed to reopen in California, Governor Gavin Newsom made the country’s most aggressive reopening reversal amid his state’s spike in COVID-19 cases, shuttering all indoor dining, bars, zoos, and museums in the state. Similar reversals have occurred in Colorado, Florida, Louisiana, Michigan, New Mexico, Oregon, Texas, West Virginia among other states.

Image for post
Image for post
Image for post
Image for post

“We’ve seen a patchwork of flip-flopping state policies across the country,” says Aral, the senior author of the study. “The problem is that, when they are uncoordinated, state re-openings and even closures create massive travel spillovers that are spreading the virus across state borders.

The new study showed that while closures directly reduced mobility by 5% –6%, re-openings returned mobility to pre-pandemic levels. Once all of a state’s peer states (in travel or social media influence) locked down, focal county mobility in that state dropped by an additional 15%–20% but increased by 19%–32% once peer states reopened. “State policies have effects far beyond their borders,” says Aral. “We desperately need coordination if we are to control this virus.”

When an origin county was subject to a statewide shelter-in-place order, travel to counties yet to impose lockdowns increased by 52%–65%. If the origin had reopened, but the destination was still closed, travel to destination counties was suppressed by 9–17% for nearby counties and 21%–27% for distant counties. But when a destination reopened while an origin was still closed, people from the closed origins flooded into the destination by 11%–12% from nearby counties and 24% from distant counties. “People flee closures and flood into newly reopened states,” says Aral, “we can’t avoid the travel spillovers caused by our ad hoc policies.”

These findings highlight the urgent need to coordinate COVID-19 reopenings across regions and the risks created by ad hoc local shutdowns and reopenings. In addition, the results highlight the importance of taking spillover effects seriously when formulating national policy and for national and local policies to coordinate across regions where spillovers are strong.

Originally published at https://mitsloan.mit.edu on September 8, 2020 and at MIT IDE here.

Read the full research paper here.

MIT Initiative on the Digital Economy

The IDE explores how people and businesses work, interact…

MIT IDE

Written by

MIT IDE

Addressing one of the most critical issues of our time: the impact of digital technology on businesses, the economy, and society.

MIT Initiative on the Digital Economy

The IDE explores how people and businesses work, interact, and prosper in an era of profound digital transformation. We are leading the discussion on the digital economy.

MIT IDE

Written by

MIT IDE

Addressing one of the most critical issues of our time: the impact of digital technology on businesses, the economy, and society.

MIT Initiative on the Digital Economy

The IDE explores how people and businesses work, interact, and prosper in an era of profound digital transformation. We are leading the discussion on the digital economy.

Medium is an open platform where 170 million readers come to find insightful and dynamic thinking. Here, expert and undiscovered voices alike dive into the heart of any topic and bring new ideas to the surface. Learn more

Follow the writers, publications, and topics that matter to you, and you’ll see them on your homepage and in your inbox. Explore

If you have a story to tell, knowledge to share, or a perspective to offer — welcome home. It’s easy and free to post your thinking on any topic. Write on Medium

Get the Medium app

A button that says 'Download on the App Store', and if clicked it will lead you to the iOS App store
A button that says 'Get it on, Google Play', and if clicked it will lead you to the Google Play store