How long should social distancing last?
March 13, 2020 7:36 PM   Subscribe

Another coronavirus question: Are any experts discussing how long the social distancing efforts and event cancellations undertaken in many countries have to last to effectively flatten the curve?

I'm concerned about this in both directions: both the substantial disruptions that people are already experiencing, and also I'm worried that in a couple weeks people will go back to business as usual and instead of a flattened curve we'll end up with exponential growth, just delayed a little bit. So I'd be interested to read any expert opinions on how long these measures need to last in order to sufficiently curb the virus' spread.
posted by Tehhund to Health & Fitness (23 answers total) 19 users marked this as a favorite
 
Dr. Anthony Fauci thinks it'll peak in about eight or nine weeks. And then once we hit the peak, it'll take some time to drop back down again, obviously. So expect disruptions to continue for quite a while.
posted by Blue Jello Elf at 7:40 PM on March 13 [4 favorites]


I was just about to ask something like this, so hope it's ok if I piggyback. the elderly &/or immunocompromised are of the greatest concern, obviously. in my case, my mom is 77, & my dad is 87 with emphysema -- highest risk imaginable. is it possible folks like them will need to hunker down until there's a vaccine? ...which is as many as 18 months away?
posted by changeling at 8:01 PM on March 13


Guardian: Australia's chief medical officer says an infection could take some months to go right through the community
"If we get a large outbreak and we can flatten the curve, it could go well into the middle of the year before it peaks. But there are some countries ... which seems to have peaked quite early and controlled the outbreak. One of the things we know about outbreaks and epidemics as they are very hard to predict."
Worst-Case Estimates for U.S. Coronavirus Deaths (NYT / MSN reprint)
Officials at the U.S. Centers for Disease Control and Prevention and epidemic experts from universities around the world conferred last month about what might happen if the new coronavirus gained a foothold in the United States. [...] The assumptions fueling those scenarios are mitigated by the fact that cities, states, businesses and individuals are beginning to take steps to slow transmission, even if some are acting less aggressively than others. The C.D.C.-led effort is developing more sophisticated models showing how interventions might decrease the worst-case numbers, though their projections have not been made public.

“When people change their behavior," said Lauren Gardner, an associate professor at the Johns Hopkins Whiting School of Engineering who models epidemics, “those model parameters are no longer applicable,” so short-term forecasts are likely to be more accurate. “There is a lot of room for improvement if we act appropriately.” Those actions include testing for the virus, tracing contacts, and reducing human interactions by stopping mass gatherings, working from home and curbing travel.

[...] The Times obtained screenshots of the C.D.C. presentation, which has not been released publicly, from someone not involved in the meetings. The Times then verified the data with several scientists who did participate.

[...] Independent experts said these projections were critically important to act on, and act on quickly. If new infections can be spread out over time rather than peaking all at once, there will be less burden on hospitals and a lower ultimate death count. Slowing the spread will paradoxically make the outbreak last longer, but will cause it to be much milder, the modelers said.
posted by katra at 8:22 PM on March 13 [1 favorite]


also I'm worried that in a couple weeks people will go back to business as usual

What does the coronavirus mean for the U.S. health care system? Some simple math offers alarming answers (Liz Spect, STAT News, Mar. 10, 2020)
This exercise can inform our level of urgency and equip us to anticipate non-obvious, second-order effects, some of which can be mitigated with proper preparation.

[...] At a 10% hospitalization rate, all hospital beds in the U.S. will be filled by about May 10. And with many patients requiring weeks of care, turnover will slow to a crawl as beds fill with Covid-19 patients.

If I’m wrong by a factor of two regarding the fraction of severe cases, that only changes the timeline of bed saturation by six days (one doubling time) in either direction. If 20% of cases require hospitalization, we run out of beds by about May 4. If only 5% of cases require it, we can make it until about May 16, and a 2.5% rate gets us to May 22.

[...] Importantly — and I cannot stress this enough — even if some of the core assumptions I’m making, like the fraction of severe cases or the number of current cases, are off even by several-fold, it changes the overall timeline only by days or weeks.

Unwarranted panic does no one any good, but neither does ill-informed complacency. It’s inappropriate to assuage the public with misleading comparisons to the seasonal flu or by assuring people that there’s “only” a 2% fatality rate. The fraction of cases that are severe really sets Covid-19 apart from more familiar respiratory illnesses, compounded by the fact that it’s whipping through a population without natural immune protection at lightning speed.
posted by katra at 8:45 PM on March 13 [13 favorites]


The Coronavirus started in Wuhan in December - first couple of cases were publicly reported 12/31/19. They had just five new cases yesterday, the second day in a row the total was below 10. So I figure with very aggressive containment we might be looking at something like three months to get to the point where it might seem safe to start to ease up. So, I doubt just a couple of weeks would be enough.
posted by metahawk at 10:06 PM on March 13


The thing to remember about flattening the curve is that it doesn't reduce the number of cases -- that's no longer possible -- it just spreads them out so as not to overwhelm hospital capacity. From epidemiologists I've talked to, we're probably looking at a minimum of 6-8 weeks disruption.
posted by basalganglia at 2:29 AM on March 14 [12 favorites]


"The Coronavirus started in Wuhan in December - first couple of cases were publicly reported 12/31/19. They had just five new cases yesterday, the second day in a row the total was below 10. So I figure with very aggressive containment we might be looking at something like three months to get to the point where it might seem safe to start to ease up. So, I doubt just a couple of weeks would be enough."

There is no sign that the US is going to engage in the level of containment China attempted, however
posted by wooh at 3:06 AM on March 14 [10 favorites]


I think you might find this press conference very interesting: https://www.youtube.com/watch?v=xRadMzCKnCU

Most of the UK's immediate peers (geographically and economically) are moving into a phase of "banned gatherings of '>n' people" or "social distancing" but the UK position, as outlined here, is that it's still too early for them to do that. One of the science advisers that speaks after Boris Johnson makes an explicit mention of behavioural science being important in addition to epidemiology.

The argument is that the best eventual outcomes are for either a quick vaccine/treatment (very unlikely), the infection hitting a barrier like hotter weather or mutation (total unknowns) or herd immunity once it has infected a high percentage of the population. If you stagger your social counter measures you can "flatten the curve" in a steady way and hence achieve the final herd immunity option without your healthcare being overloaded and associated deaths. If you go to full social distancing too soon you find that 2 weeks later people give up on it and return to life, right at the point enough of their peers are contagious for the infection to be spreading rampantly. Basically exactly the scenario your suggesting in the question.

The press conference out lines a strategy of "hold your nerve" and "tend to the herd".

A LOT of people don't like this and think the UK should be going full lock down asap. But at the very least they have to be commended for putting the science officers front and centre and explaining the plan with actual data and thought processes outlined and a realistic appraisal ("a lot more people than we say in the numbers are infected" and "a lot of people are going to die" being two paraphrasing of things they said that governments don't normally like to say).

As I say - a LOT of UK people are very concerned this response isn't "big" enough and that waiting before a bigger lock down is an error. And private organisations (sports leagues, retailers, employers) have already overtaken them in many ways anyway. But if you watch this and see the people that speak after Johnson explain WHY this is the plan, and then compare that to Trump's address of a similar time. Wow, the comparison is mind boggling to say the least.

Now to personalise a little - I am UK based and am one of 4 people that provide "light care" for a 96 year old that lives in her own apartment and has underlying health conditions. We as a group have already moved to "social distancing" and she is only having anyone enter her flat "by appointment" and with hospital-style precautions (scrub washing, 2nd skin sacrificial gloves, masks etc). Perhaps this is overkill, but her cohort's mortality rate is very very high and she is mentally a very resilient person who is able to use video chat and to cook for herself. So she is confident she can do that for weeks. So we're ahead of the government position. But that is only because we know we can commit to a long slog. I speak to other people and many of them are extreme flippant about it. If the government was telling people to stay home I really really don't think it'd hold for very long. There isn't as much commitment in the populous at large as would be required. So personally I'm very conflicted. I don't think china style lockdowns, or even Italy style, would work given what people have said to me. But my concern is less the "herd" and more my immediate circle so we've gone ahead a little.
posted by samworm at 3:19 AM on March 14 [15 favorites]


Yesterday they announced school closures in my country which will last until at least the end of April. My employer also started to strongly encourage remote working with immediate effect and until further notice. My feeling is that I’ll be working remotely until at least the end of April now.
posted by koahiatamadl at 3:23 AM on March 14 [2 favorites]


The thing to remember about flattening the curve is that it doesn't reduce the number of cases -
Which, incidentally, is why a LOT of the graphs/memes on this are wrong, including at least one of the CDC’s . There should be equal area under both graphs, but most show the flatter graph also being lower area/less cases.
posted by SaltySalticid at 5:23 AM on March 14 [5 favorites]


I think the UK approach is extremely irresponsible. What we can see in plain sight is that there is already a strain on the healthcare system in the early stages of the spread in the countries where it has begun. Was it here that someone said (paraphrasing): "look around at your local hospital, are there empty wards or bored staff? Didn't think so. Now add just ten extra intensive care patients a week." I have actually spent some time in my local hospital's intensive care ward (holding my gram's hand), and there were 14 beds, all filled at almost all times. An intensive care bed needs a full time nurse at all hours, so that's three nurses pr. patient. Where will they come from, even when you just double the need for care?
The NHS was already a bit run down before the Brexit madness, and now thousands of staff have left. I saw that press conference as an attempt to add a bit of sciencey Hokus Pokus to the fact that the UK government cannot handle this at all. It's terrible.
posted by mumimor at 5:55 AM on March 14 [13 favorites]


My organization has access to a lot of very credible scientific information as part of the work we do. We went to full work-from-home for all staff yesterday. Although I told them we would review at the end of March, our best estimate is that we won't be back to anything near normal before the end of June at the earliest.
posted by rpfields at 6:01 AM on March 14 [3 favorites]


UK to ban mass gatherings in coronavirus U-turn
Reading the article, I noted that the UK has fewer registered cases than Denmark but far more deaths. (In Denmark there is maybe one death, the doctors have not been able to establish wether he died from the virus or his pre-existing heart disease). The most likely cause is that the UK is testing less, not that relatively more patients die.
Also: Newborn baby tests positive for coronavirus in London
posted by mumimor at 6:23 AM on March 14 [2 favorites]


In the UK, they are expecting the peak to be in early May (if they can flatten the curve). When asked about school closures Nicola Sturgeon (First Minister of Scotland) said that if they did close them it was likely to be until June.

As samworm explained, your question is exactly the thing that the British Govt are worrying about.
posted by plonkee at 9:10 AM on March 14


How Much Worse the Coronavirus Could Get, in Charts (Nicholas Kristof and Stuart A. Thompson, NYT Opinion)
(The figures are for America, but the lessons are broadly applicable to any country.)

[...] successful interventions are crucial because they flatten the curve: We are much better off if the 100 million infections occur over 18 months rather than over 18 weeks.

[...] At this point we may already have tens of thousands of infections in the United States — no one knows, because testing has been catastrophically bungled — and the number of cases is probably doubling every six days or so. In these circumstances, stopping a few new cases from Europe may not matter so much.

[...] We’ll be honest: We worried that the clean lines in the graphics here risk suggesting a false precision. None of us know what lies ahead. But the wise uncertainty of epidemiologists is preferable to the confident bluster of television blowhards. The one thing we can be confident of is that enormous risks lie ahead — including a huge loss of life — if we don’t take aggressive action.
posted by katra at 9:18 AM on March 14 [3 favorites]


With regards to the top-favorited answer in this thread – this is one of the people I was thinking of when I spoke to "borrowing the cloak of medical authority that you have no right to" in a MeTa comment.

This is not an epidemiologist or an M.D., this is someone who is an engineer who claims as her authority for these statements that she routinely does these "back-of-the-envelope calculations".

If that was sufficient to be an epidemiologist, then the two professions would be the same. They're not.

There are a lot of people speaking with the cloak of authority drawn around them nowadays. There are much fewer who have actually earned it. Discerning between the two for yourself is a process known as information hygiene, and during national or international crises, it's an essential hygiene to practice.
posted by WCityMike at 11:51 AM on March 14 [12 favorites]


" ... Liz Specht, the associate director of Science and Technology for the Good Food Institute ... "
posted by WCityMike at 11:53 AM on March 14 [2 favorites]


With regards to the top-favorited answer in this thread – this is one of the people I was thinking of when I spoke to "borrowing the cloak of medical authority that you have no right to" in a MeTa comment.

Which reminds me to mention that I had failed to include the data from the CDC, which would have been more responsive to the question (emphasis mine), in the comment that currently has no love from a favorites standpoint:
The C.D.C.’s scenarios were depicted in terms of percentages of the population. Translated into absolute numbers by independent experts using simple models of how viruses spread, the worst-case figures would be staggering if no actions were taken to slow transmission.

Between 160 million and 214 million people in the United States could be infected over the course of the epidemic, according to one projection. That could last months or even over a year, with infections concentrated in shorter periods, staggered across time in different communities, experts said. As many as 200,000 to 1.7 million people could die.

And, the calculations based on the C.D.C.’s scenarios suggested, 2.4 million to 21 million people in the United States could require hospitalization, potentially crushing the nation’s medical system, which has only about 925,000 staffed hospital beds. Fewer than a tenth of those are for people who are critically ill.
posted by katra at 12:25 PM on March 14 [5 favorites]


Harvard Global Health Expert: Mass. Hospitals Face Capacity Problem If Coronavirus Cases Spike Quickly (WBUR News, Mar. 10, 2020) (emphasis mine)
Dr. Ashish Jha has spent the past day evaluating how prepared hospitals in Massachusetts are to deal with a potential onslaught of COVID-19 patients here. Jha is director of the Harvard Global Health Institute. He's also an internist, a professor of medicine at Harvard Medical School, and the K.T. Li Professor of Global Health at Harvard T.H. Chan School of Public Health. [...]

"Some of the best epidemiologists in the world are estimating that between 40 and 70% of adults will end up getting an infection. Even if we begin with that low end of 40% of adults in Massachusetts, that's 2 million people getting infected. If we take data from China that says 20% of people needed hospitalizations, that's 400,000 hospitalizations. Even if we said 'No, that's too many, we can cut that in half,' that's 200,000 hospitalizations. At any given time in Massachusetts, we think there are [3,000 to] 4,000 hospital beds open at most ... And so, if you start doing the numbers, you very quickly realize we do not have anywhere near capacity to take care of tens of thousands of people with [COVID-19] who might need hospitalization ... But if we can spread that out over many, many, many months — ideally a year — then I think we have a shot of being able to take care of everybody who will need the care."

[...] "Once we finally fix the testing problem, which hopefully will happen very soon and we can test people more broadly, some of those beds will open up. But I think it's a matter of weeks, not months, before hospitals face a real crunch. And what hospitals are going to have to do is they're going to have to cancel elective surgeries. They're going to have to think about converting things like operating rooms into ICUs. They're going to have to think about where else they can put patients and take care of them safely. We're going to have to start thinking about things like ambulatory surgical centers, and can we use them as places for very sick people. We're going to get very, very creative about expanding the supply of hospital beds and ICU beds, particularly if we're going to get through this period."
posted by katra at 12:46 PM on March 14 [6 favorites]


Coronavirus in N.Y.: Will a Surge in Patients Overwhelm Hospitals? (NYT)
Mayor Bill de Blasio has predicted that there could be 1,000 cases in the city by next week, and some doctors are expecting many more. The fundamental question for hospitals is not how many New Yorkers will get sick during the pandemic. It is how many at any given time, and whether the hospitals will have enough beds, workers and ventilators, which the most seriously ill will need to breathe.

There are about 53,000 hospital beds in New York State, including about 3,200 intensive-care unit beds, according to the American Hospital Association. About 20,000 of the beds are in the city, according to Mr. de Blasio. And officials have said there are about 5,000 ventilators in New York City — although many are already being used to keep patients — including stroke victims and others — alive.

The issues facing New York’s hospitals echo the challenges facing health care providers across the country. The World Health Organization says there are fewer hospital beds per capita in the United States than in most other nations, including in Italy and in China, where the coronavirus originated with devastating consequences.

[...] Officials emphasize that most coronavirus cases do not require hospitalization, and that they are trying to slow the spread of the virus through so-called social distancing measures, including closing public spaces, banning large gatherings and asking people to work from home. [...] The spike in cases has unsettled some health care administrators and doctors, who are mindful of what has happened in northern Italy, where in less than three weeks, the virus has inundated hospitals with patients, offering a glimpse of what countries face if they cannot slow the outbreak.
Surgeon General advises hospitals to cancel elective surgeries (Politico)
The nation's top doctor on Saturday urged a widespread halt of hospital elective procedures amid mounting concern that the health system doesn't have enough beds to manage a potential surge of coronavirus cases.
posted by katra at 12:58 PM on March 14 [3 favorites]


[One comment deleted; let's please focus on answering OP's specific question "Are any experts discussing how long the social distancing efforts and event cancellations...have to last to effectively flatten the curve?"]
posted by LobsterMitten (staff) at 1:40 PM on March 14 [1 favorite]


How will country-based mitigation measures influence the course of the COVID-19 epidemic? (Roy M Anderson, Hans Heesterbeek, Don Klinkenberg, T Déirdre Hollingsworth, The Lancet, Mar. 9, 2020, DOI:https://doi.org/10.1016/S0140-6736(20)30567-5 (via) (emphasis mine)
The greater the reduction in transmission, the longer and flatter the epidemic curve (figure), with the risk of resurgence when interventions are lifted perhaps to mitigate economic impact.

[...] Individual behaviour will be crucial to control the spread of COVID-19. Personal, rather than government action, in western democracies might be the most important issue. Early self-isolation, seeking medical advice remotely unless symptoms are severe, and social distancing are key. Government actions to ban mass gatherings are important, as are good diagnostic facilities and remotely accessed health advice, together with specialised treatment for people with severe disease. [...] If measures are relaxed after a few months to avoid severe economic impact, a further peak is likely to occur in the autumn (figure).

[...] There are difficult decisions ahead for governments. How individuals respond to advice on how best to prevent transmission will be as important as government actions, if not more important.
posted by katra at 8:33 PM on March 14 [1 favorite]


How long will social distancing for coronavirus have to last? Depends on these factors. (WaPo, Mar. 16, 2020)*
In the latest sign of how bad and how long this crisis could last, the Centers for Disease Control and Prevention said Sunday that all gatherings of more than 50 people should be halted for the next eight weeks. On Monday, officials in several states said millions of students may have to stay out of school for the rest of the academic year.

[...] We could see such second or third waves of outbreaks in countries still recovering from the first. Some experts think the virus will eventually infect 40 to 70 percent of the world’s population.

So it’s possible, even most likely, that after U.S. cases peak, Americans will still have to maintain some measures — such as isolating the infected, constant hand-washing, some degree of social distancing — until a viable vaccine is developed, which could take 12 to 18 months.
* "The Washington Post is providing this story for free so that all readers have access to this important information about the coronavirus."
posted by katra at 10:34 AM on March 16


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