How many victims before we all know someone?

The Quarantine Zone
1

Statistically speaking, how many people become sick with something, before everyone knows someone with the disease?

My naive idea is that if a fraction “f” of the population has the illness, that’s also the chances of knowing a victim. The US has roughly 330 million people, and right now has over 0.5 million corona virus cases. I’d say there’s a (0.5 million/330 million) = 1/(2*330) = 1/660 chance of knowing someone with the disease. That must assume that the cases are distributed randomly, and that everyone has similar numbers and distributions of friends/relatives/co-workers/other contacts. If I’m right, then if an average person knows over 660 people, then they’re likely to know at least one person with covid-19.

I know someone who’s had it, and is fortunately pretty much recovered. Another friend probably has it, but his initial test was negative. I know of a few more friends-of-friends who got sick, including two who died. Do I know a thousand people? Maybe, what with online friends, and co-workers.

But this does not jibe with the “six degrees of separation” idea. Or the birthday problem, which seems similar.

Any 'Dopers have a better approach for me to figure out how many people can fall ill to the awful disease before it’s likely that everyone in the population will know someone with it? Thanks in advance for reducing my ignorance!

2

2% is what I have read. Maybe it was a NY Times article. It was based on the Spanish Flu pandemic, where everyone of that generation knew someone who died. A relative, a neighbor, a co-worker.

3

Probability is NOT my strong point, but doesn’t your math assume everyone knows just one other person?

Are you asking if people know someone who died, or someone who has or had the disease?

I am fortunate that I’m not aware of anyone I know dying, but just today I learned that a woman I know and her teenaged son are sick and havw tested positive.

4

It also depends on your definition of “know.” I have maybe 10 people I consider really close friends. Then, I have all the people in my family I am in regular contact with, which is about 30 people. Then, there are the members of the minyan at synagogue, whop are all people I think very fondly of, but not all of whom I know well enough to call friends. That’s about 30 more people. I know all the people I work with. That’s probably 40 people. If you add in the kids and their families, that’s about 400 more people. I could name on sight about 1/2 the members of my synagogue, but I don’t know in what sense I really “know” them. There are probably 30 people who work in the synagogue who are not part of the school system-- they are clergy, admin, or maintenance-- so I don’t think of them as “co-workers,” but they are people I in some sense “know.” There are probably 10 people in my building I say “hello” to by name. Maybe 25 people I would recognize out somewhere as people who live in the same complex, but I don’t know by name.

Then, there are all the people I “have known,” or people I know in former places or schools I keep up with a few times a month, but while they may have once been very close friends, are not now.

So it’s a lot of people, but what is the point? Would I “know” someone who had COVID-19 if the guy I friended on Facebook because his comments on my brothers posts always made me laugh, caught it? What if someone one the board had a confirmed case? Or does it have to be someone I have met face to face at least once? Or at least once in the last 10 years? I met the actress Gemma Jones face-to-face, once, and shook her hand. Do I know her?

Then, there are probably people who don’t disclose. If I absolutely definitely knew that my 3-day illness in Feb-March was COVID-19, and I could produce a negative test in writing, I’m not sure I’d go bragging about it. I’ll bet that for a while, at least, a cloud is going to linger over recovered people when they go out in public, to the point where it will not be to their advantage to disclose.

“Hey! Wear a mask, Dude!”
“Don’t need to; had it two months ago. Have immunity. Wanna see my test results?”
Other guy ducks and runs away.

Yeah, I’d wear the mask just to avoid questions.

You need to define your terms.

This reminds me of some math a friend of mine once did to figure out by what generation all Jews would be descended from at least one Holocaust survivor. It was some time around 2100. All actual Holocaust survivors by then would be dead. He predicted that by that time, Holocaust Remembrance Day would be much less solemn, and more of a holiday, like all the other “Yay! Someone tried to kill us but didn’t do it!” Holidays. To be perfectly honest (and my uncle married into a survivor family, and my favorite person in the world besides my husband and son is my aunt-by-marriage), I hope that does happen some day.

Anyone think that some day in the future, whatever date lockdown officially ends will be commemorated?

5

In my lifetime, 3 million Americans have been murdered, and 3 million more killed in car crashes. I didn’t know any of them. But I’ve known five suicides, and two killed in plane crashes.

6

I seem to recall some years ago about a thing where everybody knows somebody who knew or knew of …

The number was 60,000. It was said with that many people everybody knew somebody who died in the Vietnam war or knew somebody who had died in a car crash within the past year. The number included acquaintances ‘next to’ the death, like your butcher’s daughter or your hairdresser’s son.

7

As soon as one person in Rhode Island had it everybody in the state knew someone who knew someone who had it.

8

Maybe - I’m barely better than guessing here, and I must have a pile of unconsidered assumptions.

I assume that if I get a formula for the odds an average member of the population knows someone who has/had corona virus, I’d be able to calculate the odds of that same average person knowing someone from the smaller group that died from it.

I am sorry about your friend and her family.

9

All good questions! For the purposes of this thread, I’d want “know someone who” to be expansive. I’m trying to see at what point the “hoax” or “fake news” or “just the flu” arguments can no loner work, because co-worker/high school friend/cousin/neighbor/grandparent/parent/sibling/spouse has it.

Interesting point about Yom Hashoah becoming just another Jewish holiday.

My guess is there won’t be one “unlock” day, most likely different places having different relaxing of the self-isolation rules. If any of that is done too soon, they’ll be another wave of infections and deaths.

10

I had a doctor appointment about 2 weeks back and he told me a decades long friend of his had just died the day before and that he personally believes that before this is over, we will all know someone that has passed from Covid-19. I only know one person who has been traipsing around like nothing is wrong, everyone else has been following guidelines. Well, one other person has been wearing a mask but still feels the need to go out to the store every damn day for “snacks”. Don’t even get me started on that.

Anyway, I figured it would be quite a while, perhaps not at all, before anyone I know got taken; not even the traipser because she is one of those people who always manages to get a pass on everything and the junk food fiend was staying indoors otherwise. Last Monday I find out that someone I have known for probably 20 years had just died from Covid-19. He was hospitalized a few days before and I had not heard. His wife also tested positive but is self-quarantined.

I believe just “knowing” someone with Covid-19 is pretty much guaranteed in the not too distant future, but I do think we are leaning towards what my doctor said; that we will all know someone who died from it.

Here in NJ, we went from 178 cases and 2 deaths to 44,416 cases and 1,232 deaths in 3 weeks, and this is with testing being the next best thing to impossible 3 weeks ago to the much more recent you’ve got a shot at it if you’re sick enough and can get to a drive-thru testing center or are sick enough to be admitted to the hospital. Until Gov Murphy ordered grocery stores to not let anyone without a mask in a couple of days ago, I kid you not, 75% of the people in the store and none of the employees had protection. And the social distancing? I waited for a lady to finish her produce selection and went up to the bin for my turn and in a flash another woman with no protection at all rushes over and starts selecting her items right beside me. Too many people are not taking this seriously enough even now and it’s still spreading.

11

I’m in NY. I know six people who have been diagnosed with the virus. One was hospitalized and released, and doing ok. Sadly, another is still in hospital and is on oxygen. Not ventilator tho. So we’re hopeful.

12

LurkerInNJ and Declanium, I am sorry about your bad news, and I wish everyone the best going forward. These are hard times.

13

I think you’re going to have to know someone hospitalized or who died from the virus to really have it impact you. If I remember correct socialists believer the a person can know about 150 people closely. So if you start there we would need about 0.6% to be hospitalized or worse. If we assume 20% get hospitalized then we need about a 3% infection rate or about 1.5 times worse that it currently is. I’d guess by the time we get to about 50k deaths everyone will believe its real.

14

To my mind, “Know someone” means someone who you would be able to say hello and address one another by name (at some point; you can know someone 25 years ago but not know them now.)

That would require many, many more people die for essentially everyone who isn’t an actual hermit to know someone who died of COVID-19.

15

My GF worked with someone who had a relative in another state who died . That’s the closest connection to me.

16

For purposes of this thread, how do you define “everyone”? If you literally mean everyone, it seems to me it may never happen. There’s got to be some remote tribe in a hard-to-access part of the world that never comes in contact with the disease.

17

I meant everyone in a given population. Since I’m in the US, my first thought is the US population.

I’m also being careless with statistical terminology. A better posed question is something like “what are the odds that a random person in the populace knows someone in the same population who has covid-19”. I’m not a statistician, please chime in to correct my terminology.
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18

I’m sorry, Bijou Drains.

19

That depends on if you know your definition of “knows.” How close do you have to be to qualify? Probably 98% of the US population knows who Tom Hanks is.

20

Actually, I like your rephrased question. No clue what the answer is, but I’d be interested in reading the analysis if someone else did it.

Also, because some people have been asking the criteria for the term “know” – the informal criteria I’ve been using if it’s someone that you’ve personally been around, like your coworker or your friend. I’ve talked to people who tell me about how their friend’s mom died, or their uncle’s coworker died, and in my eyes, that’s a stranger. Someone who goes to your church whose face you don’t recognize is also a stranger.