Ending Wuhan's social distancing too soon may spur 'second wave' of COVID-19 in midsummer

[Judi Lynn]

By Rachael Rettner - Senior Writer an hour ago

The findings have implications for the rest of the world as COVID-19 cases continue to surge outside of China.

Social distancing measures in Wuhan, China — where the outbreak of the new coronavirus disease, COVID-19, began — likely reduced the number of COVID-19 cases and delayed the peak of the epidemic, according to a new study.

What's more, the findings suggest that if these measures — including school and workplace closures — are lifted too soon, a second wave of cases may occur in midsummer. However, keeping these measures in place until early April — which the city plans to do — and gradually resuming activities would likely delay this second wave of cases until the fall; giving the health care system much-need time to expand and respond to the epidemic, the authors said.

"The unprecedented measures the city of Wuhan has put in place to reduce social contacts in school and the workplace have helped to control the outbreak," study lead author Kiesha Prem, of the London School of Hygiene & Tropical Medicine in the United Kingdom, said in a statement. "However, the city now needs to be really careful to avoid prematurely lifting physical distancing measures, because that could lead to an earlier secondary peak in cases. But if they relax the restrictions gradually, this is likely to both delay and flatten the peak."

More:
https://www.livescience.com/social-distancing-wuhan.html

[PoindexterOglethorpe]

1. I would think that a more serious problem is that this is a truly novel virus,

meaning no one on the planet has immunity to it. Until such time as everyone has gotten it and either died or survived, or we've been able to stomp it out by some other means, it's going to be out there. And could come back.

Usually viruses and other pathogens mutate in the direction of less or even non-lethality. I know there's some evidence that this virus is doing the exact opposite, which is scary. Someone needs to explain to it that if it kills off all potential hosts, it dies also.

Interesting factoid about smallpox. For thousands of years it did terrible damage to humans. Killing many, disfiguring vast numbers. In the late 19th century, in two different parts of the planet, a new version arose, vastly less lethal, almost never leaving scars behind, and overall a far more benign disease. If you got the newer, kinder version you were probably going to survive, and now you were also immune to the original one. The original form of smallpox is known as variola major, the newer, less lethal one, as variola minor. Basically, it was on its way to becoming a childhood disease that almost everyone would survive. By the time this happened, however, we did have a way of vaccinating against smallpox, and so eventually eradicated it completely.

[Igel]

2. We've seen the now-famous "flatten the curve" graph.

Most predictions have a second peak.

The problem with that mitigation is fairly simple.

X number of people will get the disease. That number *can* change, but not much.

If you have a graph with that nice curve on it, think of the number of infected people as being the *area* under the line. That means the area under that line is going to be about the same.

A high peak with that area will lead to a quick drop off to zero. Area's all there, toute suite.

If you keep the line low early on, there are several options: (1) The line stays low but goes far, far to the right before it drops close to zero. It lasts for years and is an annoyance as it kills, but hospitals are barely inconvenienced while we're on lock down until there's a vaccine *and* the vaccine has been given to most of the population of a country. (2) You keep it fairly low so hospitals can manage, but it's more than an annoyance and we're still locked down. Risk is it can get out of control, this is an unstable scenario. (3) You manage to tamp it down, but as soon as you release restrictions you get another peak.

That last option is what most flattened-curve predictions give.

Even if you do actually eradicate the virus in an area, since different parts of the world have different programs going, it'll be really hard to prevent the virus from returning. That would require extreme measures to restrict and control travel. This would not just be airports, but might well require absolute closure of borders, both land and sea borders near international borders. If Florida's cleared and there's an outbreak in the Bahamas ...

We're still not actually sure of R0 and mortality for this bug.