3/24/20 AM Coronavirus notes: Some number crunching to explain how social distancing helps

Quick reminder, like always, that I am not a doctor. I am not an expert in any medical field. Nor should you infer from these posts that I think of myself as one. I am not. At all. These updates are my way of helping everyone sift through the riff-raff with some translation into regular English.

I know there is a lot of stuff floating around – especially on the cable news networks and social media – and my goal here is to cut through the junk and offer some insight into the science of what is going on and relay some guidance from the medical professionals.

One other quick note: There has been some “social distancing” discussion amongst those same cable news / social media folk. Now, eventually, our lawmakers are going to have to make the decision to continue this effort or not. This is why it is so important that we elect good people to make these tough decisions (that’s my one shameless plug to vote).

But what I’m going to try to do below is walk you through the reasons why scientists, mathematicians and doctors are recommending it as a means of “slowing the spread” and “flattening the curve.”

The latest statistics

Here are a few numbers from some of the reputable sites collecting and releasing data….

CDC & WHO Numbers

Total Worldwide Cases: 332,218
Total Worldwide Deaths: 14,510
Total United States cases: 33,404
— Travel-related: 449
— Close contact: 539
— Under investigation: 32,416
Total deaths: 400
States reporting cases: 50 states, District of Columbia, Puerto Rico, Guam, and US Virgin Islands

(Numbers pulled from other reliable resources) Total United States cases reported by other medical sites:

Johns Hopkins

Total Worldwide Cases: 381,621
Total US cases: 46,442
Total US deaths: 590
Total US recovered: 178 (or more, new data not available this morning)

Brian McNoldy, Senior Research Associate at Univ. of Miami’s Rosenstiel School, put this next chart together. As it notes, it is pulling numbers from the Johns Hopkins totals. It shows the double-time of cases as about two-and-a-half days.

Screen Shot 2020-03-23 at 11.02.30 PM

I went through and did some projections based on the trends during the last 10 days using the same Johns Hopkins data and came up with – roughly – the same numbers as Brian.

Screen Shot 2020-03-23 at 11.01.29 PM

This estimate makes a lot of assumptions and is based solely off of previous 10 days numbers and the estimated “doubling time” of 2.5 days. It puts the United States with about 61,000 cases by Tuesday night.

How fast does it spread?

Fast. COVID19 has an R0 value of between 2 and 3. That means for every one person that has it, that infected person can spread it to two or three other people. For reference, the regular flu R0 value is a 1.3, meaning you pass the flu on to one other person.

The higher R0 value creates the possibility for exponential growth. But, only under the right conditions as highlighted by a published paper titled, “Early dynamics of transmission and control of COVID-19: a mathematical modeling study.”

Even if the reproduction number is as high as in Wuhan in early January, it could take several introductions for an outbreak to establish, because high individual-level variation in transmission makes new chains of transmission more fragile, and hence it becomes less likely that a single infection will generate an outbreak. This factor highlights the importance of rapid case identification and subsequent isolation and other control measures to reduce the chance of onward chains of transmission.

We estimated that the median daily reproduction number (Rt) in Wuhan declined from 2·35 (95% CI 1·15-4·77) 1 week before travel restrictions were introduced on Jan 23, 2020, to 1·05 (0·41-2·39) 1 week after. Based on our estimates of Rt, assuming SARS-like variation, we calculated that in locations with similar transmission potential to Wuhan in early January, once there are at least four independently introduced cases, there is a more than 50% chance the infection will establish within that population.

The take-away from that is that four independent cases in a population show a 50-50 chance it will become established. That may feel scary. However, the researchers also found that once restrictions were in place – and followed – it trimmed the transmission rate down to below the regular flu.

But the restrictions – self isolation, social distancing, etc – are pretty strict. And it remains to be seen if the United States will implement such restrictions. And if they would even be followed.

How long are people sick? And how long are they contagious?

Sadly, this news is not good news. Harvard Medical reports the answer to both questions include “it depends” and “a while.”

On their website, Harvard Medical says that people who only experience a “mild” illness can recover within one to two weeks. While those who have more severe symptoms can suffer for six weeks or more.

On top of that, research shows that people are possibly most contagious early in the course of their illness, when they are beginning to experience symptoms. Also, researchers have detected viral genetic material in patients several weeks after they’ve recovered. Harvard notes that “the significance of these findings is not fully understood,” but they do say that it is possible people may continue to be contagious for weeks after they are feeling better. Weeks.

The CDC came out with some early estimates for the percentages of people who get sick and how sick they get. They found that about 12-percent of people end up needed to visit the hospital and about three-percent end up needing to be in the ICU. And about two-percent die from the virus.

And the more significant the symptoms and the illness, the longer it may take to recover.

Why Social Distancing matters

Researchers know this virus spreads quickly. What researchers don’t know is how each next person will react to the virus. Some may be fine while others – about 12-percent based on recent studies – may need medical attention. Because the medical enterprise doesn’t know, it is important to protect yourself – and others – from becoming infected.

I want to share a little example of how fast this thing can spread. Below is a spreadsheet showing how this infection can move. Let’s assume for a moment that I, Nick Lilja, got the virus. Thankfully, in this made up example, I am not being bothered by it. Because of that, I keep going about my business.

Screen Shot 2020-03-23 at 11.25.33 PM
Check out the XXL version of this spreadsheet here: https://live.staticflickr.com/65535/49693094697_db7977d8d1_3k.jpg

Unbeknownst to me, I infect three other people. But because I didn’t know I had it, these people didn’t know to avoid me. But since the incubation period can be between 3 and 14 days, these three people go about their lives for a few days without even knowing they are infected with the virus and are spreading it around, too.

Those three people? They infect 3 other people, too.  And so on. And you may be saying, yeah, Nick, but that doesn’t even seem like that much. And you’re right. If we stopped there, it would be 27 infected people. That would be manageable. And hopefully, everyone would survive.

But without social distancing, that trend will just continue. If you follow the math out, and three people pass it to three more people 10 total times? And you infect 59,000 people. You do that 15 total times, you infect 14 million people. You do that 20 times and you get to 3.4 Billion. With a B. Billion. Not a typo.

How is that possible? The power of doubling is pretty incredible. The power of tripling? Holy moly.

This is why social distancing matters. And why it is so important that you hang tight for the next few weeks and minimize you interaction with others.

Some quick math based on the last two topics…

I know sometimes this stuff can be tough to wrap your brain around. So I want to tell a story. Hopefully that will help. The moral of this story is, “another reason why Social Distancing matters.”

Let’s assume a few things in our story. Then do some math. Let’s assume that characters in this story  (1) infect three people, (2) have an illness last two weeks, (3) be most contagious at the start of their infection but still after recovery, (4) have an incubation time of 5 days, (5) a mortality rate is 2-percent, and (6) the percentage of severe illness requiring hospitalization is 12-percent (based on research, highlighted here).

This is not a happy story, sadly. Dave got Coronavirus. And Dave got sick. But not bad sick. Just a mild fever and coughing for 14 days. But, he infects two people on Day 5, and one on day 20 –  when he was fully incubated and while he was recovering! But he was still contagious for a full 21 days! And he infected others. Those people had similar stories. They, too, got sick for 14 days. And they too, infected others on Day 5 and Day 20.

As this continued, the Dave’s town decided to keep going on like nothing was happening. For two whole months. And here is what happened…

Total infections / total hospitalized / total recovered / Total deaths

Day 1 – 1 (Dave contracted Coronavirus, but he doesn’t know it)

Day 5 – 3 (Dave’s friends got it from Dave when they came over to a BBQ)

Day 10 – 7 (It got passed to a few people around town)

Day 15 – 14 / 1 / 1 (some more people got sick, one is in the hospital, but Dave is feeling better)

Day 20 – 29 / 3 / 3 (More people are getting sick, Dave passed the virus on to someone even though he is feeling fine, Dave’s friends are feeling better, but now three people are on ventilators)

Day 25 – 61 / 7 / 7 (More than 60 people have it now, seven are in the Hospital, but seven others are feeling better)

Day 30 – 129 / 15 / 15 / 2 (More than 100 people have it now! There are 15 people in the Hospital. Two people have died. )

Day 35 – 272 / 32 / 32 / 5 (Wow, almost 300 people now! And 32 are hospitalized. Eight are in the ICU. And five people are dead. A total of 32 have recovered)

In this example, you can see how things can get out of control, how newly infected people easily outpace recovering people, how for every person that recovers, another person is in the hospital, and how fast the first death occurs. It only took two weeks to put someone in the hospital. And it took a month for the sickness to kill two people.

By two months (60 days) into the pandemic? There are 11,289 infected people, 1354 are hospitalized, 338 are in the ICU (though many ICUs couldn’t support that number), 1351 have recovered and 225 are dead.

That is a sad story for Dave and his town.

The bigger problem?

The virus in that story spreads FAR slower than the actual virus.

In Mississippi for example the first case was found on March 11th. By March 23rd there were 240 cases. That means, at the same point in time as my story, the actual virus has infected 17 times as many people. Another way of looking at it is, comparing my example to real life, the virus is moving about 2.3 times faster. Because instead of infecting 240 people by Day 35, it did so before Day 15.

That means, Day 60 in my story will happen on Day 26 in Mississippi. And it is currently Day 13.

Moral of the story: This is why Social Distancing matters.

We are Social Distancing, but the numbers are still going up! What gives?!

This will continue to be the case for up to another two weeks. Because the incubation period is 3-to-14 days long, all of the new cases being discovered today are from people who contracted the virus between three days and two weeks ago. And the orders for social distancing started – in some places – only a handful of days ago.

There is no immediate solution to this problem. The solution will take time, and patience, and perseverance. And dedication, too.

And, a lot like farming, you won’t be able to see the fruits of your labor for a while. It may take a few weeks or up to a full month.

Things you should be doing now

I may start to include this in every post. Because I know this can all seem overwhelming at times. The sheer amount of information being kicked out by every media outlets is like an avalanche.

So, here are some things:  Stay home if you can! Gotta work? That’s understandable. Need food? Sure, head to the store. But try to skip any “for fun” activities in public where you would be interacting with others or in a place with multiple other people.

Some CDC’s guidance:

— Know where to get your local / state-level information
For Mississippi: https://msdh.ms.gov/msdhsite/_static/14,0,420.html
For Louisiana: http://ldh.la.gov/Coronavirus/
For Alabama: http://www.alabamapublichealth.gov/infectiousdiseases/2019-coronavirus.html

If you live in a state outside of the region, head to google and type in, “dept of health” followed by whatever state you live. Google should take you to that state’s department of health and on the main page, most states have a link to an update on the Coronavirus.

— Know the Symptoms
Look for things like a fever, dry cough, and shortness of breath. But also know when it may become an emergency. It becomes an emergency when you have difficulty breathing, a persistent pain or pressure in the chest, you develop general confusion, and if you develop bluish lips or face. Also recognize that body aches, weak stomach, nasal congestion, a sore throat, and other symptoms of the regular flu are not the same as the symptoms with Coronavirus.

— Stay home when you are sick
Any kind of sick. If you feel like you may have Coronavirus, call your health care provider’s office in advance of a visit. If you have any sickness, the CDC recommends to limit movement in the community, limit visitors, and practice good social distancing.

— Know if you are at a higher risk
Know what additional measures those at higher risk and who are vulnerable should take. Those at higher risk include older adults (over 60), people who have serious chronic medical conditions (like heart disease, diabetes, lung disease). Some research has indicated that people with asthma may also be included in the higher risk category.

— Take steps to mitigate your infection
The CDC recommends to “Implement steps to prevent illness” by washing high-traffic areas more often, washing hands with soap and water and if someone is sick, to isolate the sick person into a low-traffic area of the home.

— Create a Household Plan
Create a household plan of action in case of illness in the household or disruption of daily activities due to COVID-19 in the community.



Author of the article:


Nick Lilja

Nick is former television meteorologist with stints in Amarillo and Hattiesburg. During his time in Hattiesburg, he was also an adjunct professor at the University of Southern Mississippi. He is a graduate of both Oregon State and Syracuse University that now calls Houston home. Now that he is retired from TV, he maintains this blog in his spare time.

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