Issue Three: The Second-Week Crash

3.29.20 | Lessons from Hubei


There is good news and bad news in this week’s announcement that the Chinese government intends to lift travel restrictions on Wuhan by April 8th.

The good news: this would end more than two months of strict quarantine measures on the city where the novel coronavirus first emerged. Wuhan reported on March 18th that, for the first time since the outbreak began, it had no new confirmed cases of Covid-19.

The bad news is how far away we are in the U.S. from this happy milestone. Wuhan went into lockdown on January 23rd. But it took until February 18th for the outbreak there to peak. By the time Wuhan reported its last official new local transmission, the only stay-at-home orders in the U.S. were in counties around San Francisco. Crudely, based on this timeline, we might guess social distancing measures in the U.S. would have to be in place through at least May.

But it is hard to compare the two cases. Wuhan was China’s only Covid-19 hotspot. The epidemic in the U.S. has multiple epicenters, with more developing. The stay-at-home orders that have gone into effect in the U.S. are less stringent than were the restrictions in the city of Wuhan and the wider province of Hubei. The U.S. still broadly lacks the testing capacity to find and fight the virus effectively.

There is something else to consider about timing. As a disease in individuals, Covid-19 seems to develop slowly and then all at once. According to the CDC, symptoms usually don’t appear until four days after exposure, and remain mild for about a week after that. It’s usually in the second week after symptoms develop that the disease suddenly turns serious enough to require hospitalization. This turn in the second week has become a signature of the disease, as the New York Times’ science reporter Donald G. McNeil Jr. described it in a recent episode of The Daily: “It’s known as the second-week crash.

The second-week crash has implications at the population level: waves of people who are relatively healthy in the first week of their infections can spread the virus to others well before healthcare systems start to register the exponential increase in cases headed their way.

In New York City, the Covid patients in the wave currently overwhelming hospitals were likely exposed some time in early March, extending chains of transmission that began weeks before that.

New Orleans is struggling against a surge of infections, showing some of the highest rates of spread in the country. The fuse for that explosion may have been lit by the week-long Mardi Gras celebrations that ended February 25th.

Los Angeles, which saw its caseload more than triple this week to more than 1,800, held its annual marathon on March 8th.

Nearly three quarters of Americans are now under Covid-related movement restrictions. Many of those restrictions haven’t even reached the end of their first week.

// In this issue

  1. Quick Link Roundup

  2. People to Follow

  3. Lessons from Hubei

[São Paolo, March 18, 2020. Photo by Victor Moriyama for the New York Times.]

// Quick Link Roundup

  • A well sourced animated explainer on SARS-CoV-2 from the folks at Kurzgesagt, who have been producing scientifically-grounded explainers for a long time now.

// People to Follow

A small sample of the people I follow on Twitter whose posts I’ve found most helpful.

  • Marc Lipsitch. A Harvard epidemiologist who raised early alarms about the pandemic.

Marc Lipsitch @mlipsitch
The @CCDD_HSPH COVID-19 website is live! Huge thanks to Linnea DiPillo, Nikita Mahulkar, Benjamin Wallace, Rachel Sadoff, Susan Matheson
  • Helen Branswell. Senior science reporter at STAT News, who has had deep experience covering disease outbreaks and has been on the Covid-19 beat since the very start.

// Lessons from Hubei

While physical distancing measures seem to have slowed the rate of infections and deaths in several Western countries recently, these measures haven’t matched the dimensions of the program that squelched the outbreak in Wuhan. Rapidly curtailing social interactions is only half the battle — intensified disease surveillance and temporary isolation of people who are sick is also crucial, since transmission within families has been a major driver of the pandemic.

As Jeremy Page reports in the Wall Street Journal:

What really turned the tide in Wuhan was a shift after Feb. 2 to a more aggressive and systematic quarantine regime whereby suspected or mild cases -- and even healthy close contacts of confirmed cases -- were sent to makeshift hospitals and temporary quarantine centers.

The tactics required turning hundreds of hotels, schools and other places into quarantine centers, as well as building two new hospitals and creating 14 temporary ones in public buildings. It also underscored the importance of coronavirus testing capacity, which local authorities say was expanded from 200 tests a day in late January to 7,000 daily by mid-February.

The steps went beyond what's envisioned in many hard-hit Western cities. As a result, many doctors and experts say the recent lockdowns in the U.S. and Europe may slow the rise in new infections -- if properly enforced -- but still won't be enough to stop it or prevent many hospitals from being overwhelmed, as they were initially in Wuhan.

“A lot of the lessons have been lost,” said Devi Sridhar, professor of global public health at the University of Edinburgh. “A lockdown helps buy time: The only way it will work is if you actually backtrack and start figuring out who has the virus.”

The U.S., Britain and some European countries will ultimately, like Wuhan, have to establish multiple makeshift hospitals and quarantine centers to isolate more cases if they are to bring the virus under control, she said.

“Absent of divine intervention, I don't think there's any other way out of it,” she said. “We're heading in that direction: We're just doing it too slow.”

With luck, physical distancing and increased testing will bend the curve and allow the U.S. to move to stratified isolation. But with the virus spreading so widely in the U.S., it may be some time before we’re able to broadly go on offense against the pandemic. In the meantime, it would be a mistake to take China’s success at curbing the disease as an easily followed path.

This breathtaking essay in Foreign Policy gives some sense of life under China’s more authoritarian measures felt like on an individual level:

As often happens in China, they never got around to telling us what the rules were. We could see the roadblocks, and heard rumors of people being locked into, or out of, places, but were left guessing about what we were and weren’t allowed to do.

For the time being, we could still walk by the river. We noticed that the flower shops were closed, but they left funeral arrangements outside on an honesty box system. Other families were evidently more cautious: Sitting on our 16th-floor balcony one sunny afternoon, the air was suddenly cut by a young boy’s voice repeatedly howling: “I need to go out and play! I need to go out and play! I need to go out and play! I need to go out and play!”

This short documentary provides another perspective.

// Concluding thoughts

This week’s newsletter came a little later and less polished than I would have liked, as the realities of carrying on my normal workload under the pandemic have set in. I hope it’s still been helpful, and I’ll see you next Saturday.