Lessons from Wuhan

Did China's response to Covid-19 work? 2 major studies reveal lessons for the US

"We need to plan right now for what's in the coming months."

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In the United States, we are just a couple of weeks into the "new normal" of a socially distant life with Covid-19.

But in China, the effects of Covid-19 have now been felt for several months – enough time for scientists to get some hard data on what works to contain it, and, should we succeed, what a return to normal will look like.

On Wednesday, a pair of studies published in journalsThe Lancet Public Health and Science provide insight into how Covid-19 spread through China, and how important travel and social-distancing restrictions may be to controlling the disease.

First, it is important to note that each study further supports what we already know. There is one thing, above all else, that works to contain Covid-19 and it is social distancing says Sam Scarpino, co-author of the Science study and assistant professor at Northeastern University.

"What works is physical and social distancing, smart work, and case isolation," he tells Inverse.

Taken together, these studies offer some of the first overviews of just how well China's policies worked and whether other countries should try to replicate them.

They also give us a very preliminary glimpse of what a world emerging from quarantine could look like.

Should we impose a "lockdown?"

China's moves to combat the virus' spread are vastly different compared to those in place in the United States.

In late January 2020, China began to lock down cities, starting with Covid-19's seeming epicenter, Wuhan. Buses, trains, and flights in and out of the city were cancelled, and roads were blocked.

Restriction on movement on that scale has not (yet) happened in the US. While discretionary travel is discouraged in the White House's 15-day coronavirus mitigation plan, there is no official mandate that bans inter-state or city travel. By contrast, other countries affected by Covid-19, including India and Italy, have adopted similar measures to the China policies.

In the Science study, Scarpino and his colleagues used a publicly available dataset of Covid-19 cases in China, and travel data from patients, to answer two questions on everyone's minds:

How effective are lockdowns? And when do they matter most?

During the time China's Covid-19 outbreak was centered around Wuhan, the control measures to stop travel to and from Wuhan were the most effective at containing the virus' spread, the Science study reports.

In short, the lockdown worked.

The movement of coronavirus was widespread in the early outbreak before China imposed mobility restrictions. Then, transmission became local, which mitigates the effectiveness of such measures, this study finds.

But as the early outbreak waned, the effect of the lockdown waned, too, says Scarpino. That's because the virus was being transmitted locally, within cities themselves. At that point, measures like social distancing, avoiding unnecessary travel, and large-scale testing help stem the spread instead.

It is too late for the US to consider a lockdown that forbids travel to and from certain cities, Scarpino says.

"Once local transmission of Covid-19 is established, which is the case throughout the United States, mobility restrictions don't actually help that much in terms of flattening the curve," he says.

Should the case numbers drop, however, there is a case for restricting mobility once again, he says. Doing so could "stop the outbreak from reestablishing itself," he says.

But there are other, more powerful actions we can take now, too:

"What's more important than mobility restrictions is testing and isolation of individuals to prevent the reintroduction of cases," he says.

A return to normal

Looking to China, which has been dealing with Covid-19 longer than we have in the Western world, holds another important lesson, the two studies suggest.

China is seeing glimpses of normality: Apple Stores are reopening, and Wuhan has closed some makeshift hospitals built to house the initial wave of patients.

It's far from normal life, but theThe Lancet study provides a first glimpse of China as it starts to relax anti-coronavirus policies.

The study mined epidemiological data from 238 studies already conducted so far to draw its conclusions. Based on that data, the authors consider whether China should start to gradually relax their physical distancing measures in March or April.

"We need to plan right now for what's in the coming months instead of reacting to a situation once it evolves."

In their scenario, relaxing such measures would need to be gradual, with 25 percent of the workforce returning to work for two weeks, while schools stay closed. Then, 50 percent of the workforce would return in weeks three and four (schools still closed).

Finally, from weeks five and beyond, the full workforce would return, and school would resume.

If China put that plan into effect in March, we would likely see a second wave of Covid-19 infections surging around June, and peaking in August.

Beginning the policy in April, however, would push the beginning of the second wave back to August, which could give scientists more time to find treatments to curb the virus. In that scenario, the resurge would peak in October.

Waiting until April could reduce the median number of new infections by 92 percent by mid 2020, the study finds.

The Chinese government appears to be on the same page. On Wednesday, the country's officials announced they will reopen Wuhan on April 8 (right in line with this study's findings).

What does that mean for the United States?

In a statement accompanying The Lancet study, Yang Liu, a co-author of paper, says that comparing the US to China in this context is difficult.

"Our results won’t look exactly the same in another country, because the population structure and the way people mix will be different," she said.

"But we think one thing probably applies everywhere: physical distancing measures are very useful, and we need to carefully adjust their lifting to avoid subsequent waves of infection when workers and school children return to their normal routine."

Scarpino agrees withThe Lancet study's conclusions: We need to think carefully about how we might relax the measures we are implementing right now.

Despite President Trump's remarks that he would "love to have the country opened up and just raring to go" by April, both of these studies, and another study released Monday, March 23, in journal The Lancet Infectious Diseases, suggests that right now we need to stick to scientists' script: Social distancing is the aim of the game, at least for now.

So while a spring reopening date may be in China's cards, it likely is not in ours.

But that doesn't mean we shouldn't be thinking about how we plan to relax physical distancing measures in the smartest way possible now, says Scarpino.

"We need to plan right now for what's in the coming months instead of reacting to a situation once it evolves," he says.

Abstract, Science paper: The ongoing COVID-19 outbreak expanded rapidly throughout China. Major behavioral, clinical, and state interventions have been undertaken to mitigate the epidemic and prevent the persistence of the virus in human populations in China and worldwide. It remains unclear how these unprecedented interventions, including travel restrictions, affected COVID-19 spread in China. We use real-time mobility data from Wuhan and detailed case data including travel history to elucidate the role of case importation on transmission in cities across China and ascertain the impact of control measures. Early on, the spatial distribution of COVID-19 cases in China was explained well by human mobility data. Following the implementation of control measures, this correlation dropped and growth rates became negative in most locations, although shifts in the demographics of reported cases were still indicative of local chains of transmission outside Wuhan. This study shows that the drastic control measures implemented in China substantially mitigated the spread of COVID-19.
Partial Abstract, The Lancet Public Health paper:
Findings: Our projections show that physical distancing measures were most effective if the staggered return to work was at the beginning of April; this reduced the median number of infections by more than 92% (IQR 66–97) and 24% (13–90) in mid-2020 and end-2020, respectively. There are benefits to sustaining these measures until April in terms of delaying and reducing the height of the peak, median epidemic size at end-2020, and affording health-care systems more time to expand and respond. However, the modelled effects of physical distancing measures vary by the duration of infectiousness and the role school children have in the epidemic.
Interpretation: Restrictions on activities in Wuhan, if maintained until April, would probably help to delay the epidemic peak. Our projections suggest that premature and sudden lifting of interventions could lead to an earlier secondary peak, which could be flattened by relaxing the interventions gradually. However, there are limitations to our analysis, including large uncertainties around estimates of R0 and the duration of infectiousness.

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