Five years since the onset of COVID-19, stay-at-home orders proven to be effective

On March 11, 2020 the World Health Organization declared COVID-19 a global pandemic. Four days later, on March 15, life as many Americans knew it changed when states began implementing stay-at-home orders to combat the spread of the virus. This week marks the fifth anniversary of initial shutdowns in the U.S. and resurfaces the questions many people have about the effectiveness of sporadic shutdowns and stay-at-home orders.

Johns Hopkins Carey Business School Economists Alessandro Rebucci, Emilia Simeonova, and Vadim Elenev have conducted new research that helps answer such questions. And their findings are as relevant as ever, since according to the Center for Health Security at Johns Hopkins Bloomberg School of Public Health, infectious disease outbreaks now occur three times more often than 40 years ago. Experts say we are always at risk of a pandemic emerging.

The new study, recently published in Management Science, examines the impact of stay-at-home orders implemented by U.S. counties on reducing mobility in the early stages of the COVID-19 pandemic. The research reveals that SHOs not only reduced mobility in counties where they were implemented but also had significant “spillover effects” in neighboring counties. People were more likely to stay home, or reduce mobility, if their neighboring county was under a mandate, even if their own county wasn’t. These spillover effects were substantial, with mobility in those neighboring counties declining by about a third to half despite not being under a mandate.

“This result is important because it opens the possibility that a staggered implementation of SHOs might have reduced mobility more than the ‘coordinated’ implementation, which was very much advocated at the time by both the policy and academic community,” said Alessandro Rebucci, co-author of the study and professor of economics at the Carey Business School.

Spillover effects were prevalent in counties that, in addition to sharing a geographic boundary, share media markets with counties that had implemented SHOs, highlighting that information sharing through local news plays a crucial role in shaping people’s behavior in response to nearby policy changes.

The research used directional mobility data, which showed that decreases in mobility within the neighboring, “spillover counties” made up a much larger portion of the overall decline in mobility than the decrease in traffic originating in the counties with SHOs alone. Such voluntary social distancing reduced overall mobility during the pandemic, confirming the effectiveness of the staggered orders that were put in place.

The research about SHOs provides valuable insights for policymakers grappling with public health crises. By understanding the spillover effects of localized policies, authorities can hopefully develop more effective strategies for managing pandemics and other health emergencies in the future.

“Our study is the first to show that even without universal lockdowns, through staggered SHOs, Americans reached a substantial proportion of the reductions in mobility and social interactions that were mandated in some European and Asian countries,” said Emilia Simeonova, a Carey professor of health economics and co-author of the study. “The importance of these spillovers, which we show are driven by information, is a crucial element that cannot be neglected by policy evaluation.”

The study's authors also emphasize that the timing of policy adoption is crucial, and an early staggered approach, coupled with effective communication strategies, might be more successful than delayed coordinated action.