Herd immunity or flattening the curve ? This is the question to which my mother-in-law, her friend Bruna, the tinker of Blackpool and all the people of the Web are looking for an answer!

Home phone ringing in the middle of the night never brings good news.

Especially when you live away from your loved ones.

On the other end of the phone is my mother-in-law.

“Do I wake you ?”

“WTF, it’s 4:00 in the morning. Of course you wake me up. What happened?”

“No, nothing, don’t worry, it’s just…”

“Don’t worry” is exactly the signal one has to worry about.

“My mom ?”

“Hell no, what about your mom ? We had dinner together last night, we’re fine…”

“Then what?” I’m very agitated “Speak up for God’s sake!”

“No, it’s just that, you know this coronavirus thing… you hear so much about it…”

You’re the one who’s worried, rightly so. But it’s still 4:00 in the morning, jeez.

“Oh, come on. Stay safe home and have your groceries be brought to you. It’ll be all right… To spend the time, you can read my books, call your friends or video chat them, fuck around on Facebook…”

“That’s just what I wanted to talk about: Facebook.”

“At 4:00 in the morning ? Are you crazy ? Couldn’t you wait until tomorrow?”

“No, I can’t do it. I’ve been rambling ever since my friend Bruna shared a post in favor of herd immunity theory. She found, I don’t know where, the Gaussian curve that seems to support Boris Johnson wicked politics…”

“Calm down, Lucia. Can you repeat slowly, please? Herd immunity, Gaussian curves, Boris Johnson… what are you talking about ?”

“Oh, come on. England has decided not to take any restrictive measures for the covid19. Everybody knows it. Accepting the contagion up to a threshold where, thanks to the high percentage of immunity achieved, it no longer circulates. Boris Johnson with that blond hair, you know? The British voted Brexit, soon they will no longer exist and yet some statistics say they’re right in acting like that ? I mean, they’re so British, you know ? How is that possible ?”

Shit. What the fuck is she talking about?

“Oh, yeah, the statistics…”

“No, but listen to this. You know I also follow the Blackpool’s tinker on Facebook as he’s always so deep in his geopolitical analysis…”

I’m pinching myself. I can’t believe I’m up at 4:00 a.m. on the phone with my mother-in-law who’s talking to me about Boris Johnson, herd immunity, Gauss’ curves, her friend Bruna and Blackpool’s freaking tinkers.

It’s all true.

“Well, instead he supports the flattening of the curve approach,” my mother-in-law mercilessly continues.

“Well, you know, lots of heads, lots of ideas…” I try to get away from this nightmare as I can.

“Well no! You must know that in 1948, after I told her about my crush for a Filibert, Bruna accepted to dance with him at the Labor party rally… And I never forgave her. This herd immunity thing sounds like bullshit to me. I’m looking at every Gaussian distribution I can think of, but I don’t understand why one says one thing and the other one says another. They all look the same to me. Help me find something in her reasoning I can expose. Please, I’ve been waiting for this moment for 72 years!”

Oh my Lord, all I needed was my mother-in-law’s rival in love.

“Uhm, yes, the Gaussian… It’s a curve that shows the distribution of a given event as a function of a variable. For example, the distribution of coronavirus cases as a function of time. On the ordinate axis there are the cases found every day and on the abscissae axis the time elapsed since the first infection was detected. “Normally” events are always distributed in this way, in the shape of a bell, which is why we speak of Gaussian curve or “normal” curve. At the beginning events scarce, they have a central peak around the median and finally the curve turns to decrease and fade away”.

“Yes, I know. I’ve seen all these curves. But tell me something to get back at that little bitch !”

“Wait! What I’m saying is there’s no answer to your question. If there are scientific committees that support one theory as much as the other, neither you nor the Bruna nor the guy from Blackpool will be the one to disavow them. But I know that when you express your thoughts you only say things that you already know, while listening to other people’s thoughts you risk to learn new ones, so… shut up and listen to me!

So, a sharper, narrower bell means the epidemic is concentrated in a short period of time. Whereas a flatter one means holding the coronavirus longer. The difference is that, in the former, the peak of the epidemic probably exceeds the capacity of the health service. Which means that it would not be able to cure all patients. While this wouldn’t be the case in the latter.

It is just that not all coronavirus infected patients need medical care and only a small proportion need intensive care. Therefore, to truly assess the capacity of the health care system, it should be compared to the curve of those who would need it at the time of the peak and not to the total number of infections.

If, instead of time, we measured the distribution according to the severity of the patient: on the far left we would have those who are completely asymptomatic, slowly we would go towards those who have not even noticed that they have the virus, we would then meet those with a few lines of fever to end up with intensive care and the dead at the other end of the axis. Which, being in the tail of the bell, would still represent a residual number of cases.

Although common sense seems to support this conclusion, there is no certainty that the herd immunity approach would cause more deaths than the flattening the curve one. Especially as long as there is no cure. Mortality seems to be more related to the average age of the population. In Italy, which is a country of “old people” reached 10.5%, in other countries it is around 2%.

But, let’s take another example: functional illiteracy. That is, the inability to understand, evaluate and use the information available.

You should know that in Italy 47% of the population between 16 and 65 years of age falls into this category.

So, if we presented graphically the “normal” distribution of functional illiteracy in Italy, we would have a bell where on the left of the median we would find the totally illiterate people who slowly approaching half of the population (47%), can read and write but still do not understand everything they are told. When the curve reverses, beginning to descend, we meet the part of the population that begins to have a vague idea of what is said to them, and then we go down towards that 5% or less of the tail of the Gaussian where the population is sound in mind and will and in full possession of their faculties.

All this to tell you that the chances of dying of covid19 are low. And that, despite this, you, your friend Bruna, the tinker of Blackpool and 99% of those who write on social networks are less likely to understand a Gauss curve than to die of coronavirus.

So, Lucia, do me a favor: go back to sleep and stay safe home.”

“You’re right, Michele. Better think about my health. I’ll get Bruna with the electoral college system in the US anyway ! She can’t figured it out.”

“Bravo Lucia, dream of the electors, good night”

“Good night, Michele.”