Social distancing and COVID-19: A law of diminishing returns

Research finds distancing helps ease the burden on hospitals -- but only to a point

July 15, 2020

Science Daily/Washington University in St. Louis

The first case of the novel coronavirus, COVID-19, in the United States was in late January. By mid-March, "social distancing" had entered the public lexicon. People altered their routines and local jurisdictions suggested, urged, or required changes meant to slow the disease's spread.

By the end of June, however, public health officials and news outlets were talking about a second wave. In July, many states were pausing or reversing their plans to reopen while, for the second time, hospital systems worried about running out of room.

What could we have done better?

In an "editor's pick" paper published today in the journal Chaos of the American Institute of Physics, Washington University in St. Louis researchers in the lab of Rajan Chakrabarty, associate professor in the department of Energy, Environmental and Chemical Engineering at the McKelvey School of Engineering, modeled the interplay between the duration and intensity of social distancing. They found a law of diminishing returns, showing that longer periods of social distancing are not always more successful when it comes to slowing the spread, and that any strategy that involves social distancing requires other steps be taken in tandem.

"Conventional wisdom was, the more intense and long-term the social distancing, the more you will curb the disease spread," Chakrabarty said

"But that is true if you have social distancing implemented with contact tracing, isolation and testing. Without those, you will give rise to a second wave."

Added Payton Beeler, a second year doctoral student in Chakrabarty's lab, who also worked with Pai Liu, a postdoctoral fellow: "What we have found is that if social distancing is the only measure taken, it must be implemented extremely carefully in order for its benefits to be fully realized."

Their susceptible, exposed, infected, and recovered (SEIR) dynamics model used data gathered by Johns Hopkins University between March 18 and March 29, a period marked by a rapid surge in COVID-19 cases and the onset of social distancing in most US states. Calibrating their model using these datasets allowed the authors to analyze unbiased results that had not yet been affected by large-scale distancing in place.

Unique to this project was the use of age stratification; the model included details on how much people of different age groups interact, and how that affects the spread of transmission.

No matter what strategy they looked at, one thing was clear, Chakrabarty said: "Had social distancing been implemented earlier, we probably would've done a better job."

Researchers found that, over the short-term, more distancing and less hospital demand go hand in hand -- but only up to two weeks. After that, time spent distancing does not benefit hospital demand as much; society would have to increase social distancing time exponentially in order to see a linear decrease in hospital demand.

Thus the diminishing return: Society would see smaller and smaller benefits to hospital demand the longer it spent social distancing.

If social distancing "alone" is to be implemented longer than two weeks, a moderate shut down, say between 50-70%, could be more effective for the society than a stricter complete shut-down in yielding the largest reduction in medical demands.

Another strategy for flattening the curve involves acting intermittently, alternating between strict social distancing and no distancing to alleviate the strain on hospitals -- as well as some of the other strains on the economy and well-being imposed by longer-term distancing.

According to the model, the most efficient distancing- to- no-distancing ratio is 5 to 1; one day of no distancing for every five days at home. Had society acted in this way, hospital burden could have been reduced by 80%, Chakrabarty said. Exceeding this ratio, the model showed a diminishing return.

Critically, the researchers note that social distancing policy as a whole-of-government approach could not be successful without the implementation of wide-spread testing, contact tracing, and isolation of those found to be infected.

"And you have to do it aggressively," Chakrabarty said. "If you do not, what you're going to do, the moment you lift social distancing, is give rise to a second wave."

That's because the people who are leaving their homes after distancing themselves are, ostensibly, all susceptible to COVID-19.

"Bending the curve using social distancing alone is analogous to slowing down the front of a raging wildfire without extinguishing the glowing embers," said Chakrabarty, whose other line of research focuses on the impacts of wildfires on climate and health.

"They are waiting to start their own fires once the wind carries them away."

The model cannot inform strategies going forward because it used data collected in March, before any large-scale social distancing was implemented. But Chakrabarty said it may be able to inform our actions if we find ourselves in a similar situation in the future.

"Next time, we must act faster, and be more aggressive when it comes to contact tracing and testing and isolation," Chakrabarty said. "Or else this work was for nothing."

https://www.sciencedaily.com/releases/2020/07/200715160005.htm

'Feeling obligated' can impact relationships during social distancing

March 19, 2020

Science Daily/Michigan State University

In a time where many are practicing "social distancing" from the outside world, people are relying on their immediate social circles more than usual. Does a sense of obligation -- from checking on parents to running an errand for an elderly neighbor -- benefit or harm a relationship? A Michigan State University study found the sweet spot between keeping people together and dooming a relationship.

"We were looking to find whether obligation is all good or all bad," said William Chopik, assistant professor of psychology at MSU and co-author of the study. "When we started, we found that people were responding to types of obligations in different ways. People distinguished between requests that were massive obligations and requests that were simple. There's this point that obligation crosses over and starts to be harmful for relationships."

According to Jeewon Oh, MSU doctoral student and co-author of the study, obligation is sometimes the "glue that holds relationships together," but it often carries negative connotations.

"We found that some obligations were linked with greater depressive symptoms and slower increases in support from friends over time," Oh said. "However, other obligations were linked with both greater support and less strain from family and friends initially."

Chopik and Oh's findings suggest that there's a distinct point at which obligation pushes individuals to the brink of feeling burdened, which can start to harm their relationships.

"The line in our study is when it crosses over and starts to be either a massive financial burden or something that disrupts your day-to-day life," Chopik said. "While engaging in substantive obligation can benefit others and make someone feel helpful, it is still costly to a person's time, energy and money."

Until now, similar research showed inconsistencies in how obligation impacts relationships, which Chopik attributes to the spectrum of obligation. This spectrum ranges from light obligation, like keeping in touch with a friend, to substantive obligation, like lending that friend a considerable amount of money.

"In a way, major obligations violate the norms of friendships," Chopik said. "Interestingly, you don't see that violation as much in relationships with parents or spouses."

Chopik explained that friendships are viewed as low-investment, fun relationships that make people feel good.

"Our longest lasting friendships continue because we enjoy them. But if obligations pile up, it might compromise how close we feel to our friends," Chopik said. "Because friendships are a relationship of choice, people can distance themselves from friends more easily than other types of relationships when faced with burdensome obligations."

Additionally, substantive obligations may create strain in a friendship as we try to encourage our friends to do the same even when they might not be able to do so, Oh said.

"Although we may feel good when we do things for our friends, and our friends are grateful to us, we may start to feel like we are investing too much in that relationship," Oh said.

On the other end of the spectrum, light obligation creates what Chopik calls a "norm of reciprocity."

"Those light obligations make us feel better, make us happier and make our relationships stronger," Chopik said. "There's a sense that 'we're both in this together and that we've both invested something in the relationship.'"

That's why, among the best relationships, low-level acts of obligation don't feel like obligations at all. Small acts of kindness, which strengthen the bonds of our relationships, are done without any fuss or burden.

Still, some types of relationships can make even minor obligations seem daunting. If someone doesn't have a great relationship with a parent, a quick phone call to check in isn't enjoyable, it's an encumbrance.

"Even for things we would expect family members to do, some in the study did them begrudgingly," Chopik said.

Chopik and Oh's findings reveal a spectrum of obligations as diverse as the relationships one has in life.

"It's the little things you do that can really enhance a friendship, but asking too much of a friend can damage your relationship," Chopik said.

https://www.sciencedaily.com/releases/2020/03/200319125132.htm