On moral outrage.

On moral outrage.

My family had spring break travel plans for before the shutdown.

We canceled them.

At the time, we feared for our safety. My spouse said to me, “You caught the flu twice this year, even after you were vaccinated, and the second time was the sickest I’ve ever seen you. I’m really worried about what will happen if you catch this new thing, too.”

She wanted me to cancel my poetry classes in the local jail. My father, an infectious diseases doctor and professor of immunology, thought I should still go in to teach. “If somebody’s in there coughing up a lung, you should recommend he skip class next week,” my father told me.

But I was spooked. I felt glad when the jail put out a press release saying they’d no longer allow volunteers to come in – I didn’t want to choose between helping the incarcerated men and protecting my family.

My spouse is a high school science teacher. She felt glad that her biology classroom has over a dozen sinks. During the final week of school, she asked all her students to wash their hands for 20 seconds as soon as they walked into the room.

My spouse and I are both scientists, but it wasn’t until a week into the shutdown that I began to read research papers about Covid-19. Until then, we had gotten all our information from the newspaper. And the news was terrifying. Huge numbers of people were dying in Italy. Our imbecilic president claimed that Covid-19 was no big deal, making me speculate that this disease was even more dangerous than I’d thought.

Later, I finally went through the data from Italy and from the Diamond Princess cruise ship. These data – alongside the assumption that viral exposure should be roughly similar across age groups, if not higher for school children and young people who are out and about in the world – showed my family that our personal risk was probably quite low.

Still, we stayed inside. We were worried about harming others.

When I saw photographs of beaches packed with revelers, I felt furious. Did those selfish young people not realize that their choices could cause more people to die?

So it was shocking for me to learn that those selfish young people were actually doing the thing that would save most lives.

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We now know that Covid-19 can be transmitted by people who feel no symptoms, and that it was widespread in this country by March.

If we, as a people, had acted earlier, we could have prevented all these deaths. In January, it would have been enough to impose a brief quarantine after all international travel. In February, it would have been enough to use our current strategy of business closures, PCR testing, and contact tracing. In March, we were too late. The best we could do then – the best we can do now – was to slow the spread of infections.

Unfortunately, slowing the spread of infections will cause more people to die.

There’s an obvious short-term benefit to slowing the spread of infections – if too many people became critically ill at the same time, our hospitals would be overwhelmed, and we’d be unable to offer treatment to everyone who wanted it. We’d run out of ventilators.

This problem is exacerbated by the fact that we, as a people, are terrible about talking about death. There’s no consensus about what constitutes a good life – what more would have to happen for you to feel ready to die?

Personally, I don’t want to die. As my mind stopped, I’d feel regret that I wouldn’t get to see my children become self-sufficient adults. But I’d like to think that I could feel proud that I’ve done so much to set them on the right path. Since my twenties, I’ve put forth a constant effort to live ethically, and I’d like to imagine that my work – my writing, teaching, and research – has improved other people’s lives.

I’ve also gotten to see and do a lot of wonderful things. I’ve been privileged to visit four countries. I visited St. Louis’s City Museum when one of my kids was old enough to gleefully play. I have a bundle of some two dozen love letters that several wonderful people sent me.

I’ve had a good life. I’d like for it to continue, but I’ve already had a good life.

Many medical doctors, who have seen how awful it can be for patients when everything is done to try to save a life, have “do not resuscitate” orders. My spouse and I keep our living wills in an accessible space in our home. But a majority of laypeople want dramatic, painful measures to be taken in the attempt to save their lives.

People are making this choice even during the pandemic, when the choice to experience an excruciating death puts medical professionals at risk and reduces the quality of care available for everyone else.

Still. Even without our reluctance to discuss death, there would be a short-term benefit to slowing the spread of infections. The American healthcare system is terrible, and was already strained to the breaking point. We weren’t – and aren’t – ready to handle a huge influx of sick patients.

But the short-term benefit of slowing the spread of Covid-19 comes at a major cost.

The shutdown itself hurts people. The deaths caused by increased joblessness, food insecurity, educational disruption, domestic violence, and loneliness (“loneliness and social isolation can be as damaging to health as smoking 15 cigarettes a day”) are more difficult to measure than the deaths caused by Covid-19. We won’t have a PCR test to diagnose which people were killed by the shutdown.

Those deaths won’t all come at once. But those deaths are no less real, and no less tragic, than the immediate horror of a person drowning from viral-induced fluid buildup in their lungs.

And, perhaps more damning, if the shutdown ends before there’s a vaccine, the shutdown will cause more people to die of Covid-19.

Without a vaccine, slowing the spread of Covid-19 has a short-term benefit of reducing the rate of hospital admissions, at the long-term cost of increasing the total number of Covid-19 cases.

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All immunity fades – sometimes after decades, sometimes after months. Doesn’t matter whether you have immunity from recovery or from vaccination – eventually, your immunity will disappear. And, for a new disease, we have no way of predicting when. Nobody knows why some antigens, like the tetanus vaccine, trigger such long-lasting immunity, while other antigens, such as the flu vaccine or the influenza virus itself, trigger such brief protection.

We don’t know how long immunity to Covid-19 will last. For some coronaviruses, immunity fades within a year. For others, like SARS, immunity lasts longer.

The World Health Organization has warned, repeatedly, that immunity to Covid-19 might be brief. But the WHO seems unaware of the implications of this warning.

The shorter the duration of a person’s immunity, the more dangerous the shutdown. If our shutdown causes the Covid-19 epidemic to last longer than the duration of individual immunity, there will be more total infections – and thus more deaths – before we reach herd immunity.

This is, after all, exactly how a one-time “novel zoogenic disease” like influenza became a permanent parasite on our species, killing tens of thousands of people in the United States each year. Long ago, transmission was slowed to the point that the virus could circulate indefinitely. Influenza has been with us ever since.

That’s the glaring flaw in the recent Harvard Science paper recommending social distancing until 2022 – in their key figure, they do not incorporate a loss of immunity. Depending on the interplay between the rate of spread and the duration of immunity, their recommendation can cause this epidemic to never end.

And, if the shutdown ends before we have a vaccine, the lost immunity represents an increased death toll to Covid-19. Even neglecting all the other harms, we’ll have killed more people than if we’d done nothing.

This sounds terrifying. And it is. But the small glimmer of good news is that people’s second infections will probably be less severe. If you survive Covid-19 the first time you contract it, you have a good chance of surviving subsequent infections. But prolonging the epidemic will still cause more deaths, because herd immunity works by disrupting transmission. Even though an individual is less likely to die during a second infection, that person can still spread the virus. Indeed, people are more likely to spread the virus during subsequent infections, because they’re more likely to feel healthy while shedding infectious particles.

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This calculation would be very different if people could be vaccinated.

Obviously, vaccination would be the best way to end this epidemic. In order to reach herd immunity by a sufficient number of people recovering, there would have to be a huge percentage of our population infected. Nobody knows how many infections it would take, but many researchers guess a number around 60% to 70% of our population.

Even if Covid-19 were no more dangerous than seasonal influenza (and our data so far suggest that it’s actually about four-fold more dangerous than most years’ seasonal influenza), that would mean 200,000 deaths. A horrifying number.

But there’s no vaccine. Lots of people are working on making a vaccine. We have Covid-19 vaccines that work well in monkeys. But that doesn’t necessarily mean anything in terms of human protection. We’ve made many HIV vaccines that work well in monkeys – some of these increase the chance that humans will contract HIV.

It should be easier to make a vaccine against this coronavirus than against HIV. When making a vaccine, you want your target to mutate as little as possible. You want it to maintain a set structure, because antibodies need to recognize the shape of external features of the virus in order to protect you. HIV mutates so fast that its shape changes, like a villain constantly donning a new disguise. But the virus that causes Covid-19 includes a proofreading enzyme, so it’ll switch disguises less.

Still, “easier to make a vaccine against than HIV” is not the most encouraging news. Certain pharmaceutical companies have issued optimistic press briefings suggesting that they’ll be able to develop a vaccine in 18 months, but we should feel dubious. These press briefings are probably intended to bolster the companies’ stock prices, not give the general public an accurate understanding of vaccine development.

Realistically, a Covid-19 vaccine is probably at least four years away. And it’s possible – unlikely, but possible – that we’ll never develop a safe, effective vaccine for this.

If we end the shutdown at any time before there is a vaccine, the shutdown will increase the number of people who die of Covid-19. The longer the shutdown, the higher the toll. And a vaccine is probably years away.

The combination of those two ideas should give you pause.

If we’re going to end the shutdown before we have a vaccine, we should end it now.

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To be absolutely clear, vaccination would be the best way to resolve this crisis. Vaccination saves lives. The basic principle of inoculation was used for hundreds of years in Africa, India, and China, before it was adapted by Edward Jenner to create the first smallpox vaccine.

For a vaccine to end the Covid-19 epidemic, enough people will need to choose to be vaccinated for us to reach herd immunity.

Unfortunately, many people in the United States distrust the well-established efficacy and safety of vaccines. It’s worth comparing Covid-19 to seasonal influenza. On a population level, Covid-19 seems to be about four-fold more dangerous than seasonal influenza. But this average risk obscures some important data – the risk of Covid-19 is distributed less evenly than the risk of influenza.

With influenza, healthy young people have a smaller risk of death than elderly people or people with pre-existing medical conditions. But some healthy young people die from seasonal influenza. In the United States, several thousand people between the ages of 18 and 45 die of influenza every year.

And yet, many people choose not to be vaccinated against influenza. The population-wide vaccination rate in the United States is only 40%, too low to provide herd immunity.

Compared to influenza, Covid-19 seems to have less risk for healthy young people. Yes, healthy young people die of Covid-19. With influenza, about 10% of deaths are people between the ages of 18 and 45. With Covid-19, about 2% of deaths are people in this age group.

I’m not arguing that Covid-19 isn’t dangerous. When I compare Covid-19 to seasonal influenza, I’m simply comparing two diseases that are both deadly.

I get vaccinated against influenza every year.

Yes, you might have heard news reports about the influenza vaccine having low efficacy, but that’s simply measuring how likely you are to get sick after being vaccinated. We also know that the vaccine makes your illness less severe.

The influenza vaccine saves lives. The data are indisputable.

But people don’t choose to get it! That’s why I think it’s unfortunately very likely that people whose personal risk from Covid-19 is lower than their risk from influenza will forgo vaccination. Even if we had access to 300 million doses of a safe, effective vaccine today, I doubt that enough people would get vaccinated to reach herd immunity.

Obviously, I’d love to be wrong about this. Vaccination saves lives.

Please, dear reader, get a flu vaccine each year. And, if we develop a safe, effective Covid-19 vaccine, you should get that too.

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We don’t have a vaccine. The shutdown is causing harm – the shutdown is even increasing the total number of people who will eventually die of Covid-19.

Is there anything we can do?

Luckily, yes. We do have another way to save lives. We can change the demographics of exposure.

Our understanding of Covid-19 still has major gaps. We need to do more research into the role of interleukin 6 in our bodies’ response to this disease – a lot of the healthy young people who’ve become critically ill with Covid-19 experienced excessive inflammation that further damaged their lungs.

But we already know that advanced age, smoking status, obesity and Type 2 diabetes are major risk factors for complications from Covid-19. Based on the data we have so far, it seems like a low-risk person might have somewhere between a hundredth or a thousandth the chance of becoming critically ill with Covid-19 as compared to an at-risk person. With influenza, a low-risk person might have between a tenth and a hundredth the chance of becoming critically ill.

The risk of Covid-19 is more concentrated on a small segment of the population than the risk of influenza.

To save lives, and to keep our hospitals from being overwhelmed, we want to do everything possible to avoid exposing at-risk people to this virus.

But when healthy young people take extraordinary measures to avoid getting sick with Covid-19 – like the shutdown, social distancing, and wearing masks – they increase the relative burden of disease that falls on at-risk people. We should be prioritizing the protection of at-risk people, and we aren’t.

Because this epidemic will not end until we reach the population-wide threshold for herd immunity, someone has to get sick. We’d rather it be someone who is likely to recover.

Tragically, we already have data suggesting that a partial shutdown can transfer the burden of infection from one group to another. In the United States, our shutdown was partial from the beginning. People with white-collar jobs switched to working remotely, but cashiers, bus drivers, janitors, people in food prep, and nurses have kept working. In part because Black and brown people are over-represented in these forms of employment, they’ve been over-represented among Covid-19 deaths.

There is absolutely no reason to think that poor people would be more likely to safely recover from Covid-19 – indeed, due to air pollution, stress, sleep deprivation, limited access to good nutrition, and limited access to health care, we should suspect that poor people will be less likely to recover – but, during the shutdown, we’ve shifted the burden of disease onto their shoulders.

This is horrible. Both unethical and ineffective. And, really, an unsurprising outcome, given the way our country often operates.

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If we want to save lives, we need for healthy younger people to use their immune systems to protect us. The data we have so far indicates that the shutdown should end now — for them.

It will feel unfair if healthy younger people get to return to work and to their regular lives before others.

And the logistics won’t be easy. We’ll still need to make accommodations for people to work from home. Stores will have to maintain morning hours for at-risk shoppers, and be thoroughly cleaned each night.

If school buildings were open, some teachers couldn’t be there – they might need substitutes for months – and neither could some students, who might switch to e-learning to protect at-risk family.

We’ll need to provide enough monetary and other resources that at-risk people can endure a few more months of self-isolation. Which is horrible. We all know, now that we’ve all been doing this for a while, that what we’re asking at-risk people to endure is horrible. But the payoff is that we’ll be saving lives.

Indeed, the people who self-isolate will have lowest risk. We’ll be saving their lives.

And no one should feel forced, for financial reasons or otherwise, to take on more risk than they feel comfortable with. That’s why accommodations will be so important. I personally would feel shabby if I took extreme measures to protect myself, knowing that my risk is so much lower than other people’s, but you can’t look at someone in a mask and know their medical history, much less whom they might be protecting at home.

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All told, this plan isn’t good. I’m not trying to convince you that this is good. I’m just saying that, because we bungled things in January, this is the best we have.

If we could go back in time, we’d obviously do things differently. It’s only based on where we are now that physicians like David Katz argue we need to end the shutdown based on the principle of “harm minimization.”

Based on the data we have, I agree.

Ending the shutdown now, but only for some, will save lives.

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So, those selfish young people crowding on beaches? I looked at the photos and hated them.

But it turns out that their selfish actions were actually the exact plan that will save most lives.

I’ve had to swallow my moral indignation. I hope you can too.

On testing.

On testing.

UPDATE: Wow, this got a lot of readers! Honestly, though, I wrote a response to common questions and comments about this essay and it is probably a better read.

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My spouse recently sent me a link to the article “Concerns with that Stanford study of coronavirus prevalence” by Andrew Gelman, a statistician at Columbia University.  From reading this article, I got the impression that Gelman is a good mathematician.  And he raises some legitimate concerns. 

But I’ve noticed that many of the people criticizing the work coming out of the Ioannidis group – such as the study of how many people in Santa Clara county might have antibodies to Covid-19 – don’t seem to understand the biology underlying the numbers.

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First, some background: in case you haven’t noticed, most of the United States is operating under a half-assed lockdown.  In theory, there are stay-at-home orders, but many people, such as grocery store clerks, janitors, health care workers, construction workers, restaurant chefs, delivery drivers, etc., are still going to work as normal.  However, schools have been closed, and most people are trying to stand at least six feet away from strangers.

We’re doing this out of fear that Covid-19 is an extremely dangerous new viral disease.  Our initial data suggested that as many as 10% of people infected with Covid-19 would die.

That’s terrifying!  We would be looking at tens of millions of deaths in the United States alone!  A virus like this will spread until a majority of people have immunity to it – a ballpark estimate is that 70% of the population needs immunity before the epidemic stops.  And our early data suggested that one in ten would die.

My family was scared.  We washed our hands compulsively.  We changed into clean clothes as soon as we came into the house.  The kids didn’t leave our home for a week.  My spouse went to the grocery store and bought hundreds of dollars of canned beans and cleaning supplies.

And, to make matters worse, our president was on the news saying that Covid-19 was no big deal.  His nonchalance made me freak out more.  Our ass-hat-in-chief has been wrong about basically everything, in my opinion.  His environmental policies are basically designed to make more people die.  If he claimed we had nothing to worry about, then Covid-19 was probably more deadly than I expected.

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Five weeks have passed, and we now have much more data.  It seems that Covid-19 is much less dangerous than we initially feared.  For someone my age (37), Covid-19 is less dangerous than seasonal influenza.

Last year, seasonal influenza killed several thousand people between the ages of 18 and 49 in the United States – most likely 2,500 people, but perhaps as many as 5,800.  People in this age demographic account for about 10% of total flu deaths in the United States, year after year.

Seasonal influenza also killed several hundred children last year – perhaps over a thousand.

There’s a vaccine against influenza, but most people don’t bother. 

That’s shocking. 

Seasonal influenza is more dangerous than Covid-19 for people between the ages of 18 and 49, but only 35% of them chose to be vaccinated in the most recently reported year (2018).  And because the vaccination rate is so low, our society doesn’t have herd immunity.  By choosing not to get the influenza vaccine, these people are endangering themselves and others.

Some people hope that the Covid-19 epidemic will end once a vaccine is released.  I am extremely skeptical.  The biggest problem, to my mind, isn’t that years might pass before there’s a vaccine.  I just can’t imagine that a sufficient percentage of our population would choose to get a Covid-19 vaccine when most people’s personal risk is lower than their risk from influenza.

When I teach classes in jail, dudes often tell me about which vaccines they think are too dangerous for their kids to get.  I launch into a tirade about how safe most vaccines are, and how deadly the diseases they prevent. 

Seriously, get your kids vaccinated.  You don’t want to watch your child die of measles.

And, seriously, dear reader – get a flu vaccine each year.  Even if you’re too selfish to worry about the other people whom your mild case of influenza might kill, do it for yourself. 

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We already know how dangerous seasonal influenza is.  But what about Covid-19?

To answer that, we need data.  And one set of data is unmistakable – many people have died.  Hospitals around the world have experienced an influx of patients with a common set of symptoms.  They struggle to breathe; their bodies weaken from oxygen deprivation; their lungs accumulate liquid; they die.

Many people have been put on ventilators, but that’s often the beginning of the end.  Most people put on ventilators will die.  Among patients over 70 years old, three quarters who are put on ventilators will die

For each of these patients saved, three others are consigned to an agonizing death in the hospital, intubated among the flashing lights, the ceaseless blips and bleeps.  At home, they’d die in a day; in the hospital, their deaths will take three weeks.

And the sheer quantity of deaths sounds scary – especially for people who don’t realize how many tens of thousands die from influenza in the United States each year.

Or, consider: cigarette smoking causes 480,000 deaths per year in the United States, including 41,000 people who die from second-hand smoke exposure.  Those 41,000 aren’t even choosing to smoke!  But cigarettes kill them anyway.

Indeed, when people die of Covid-19, it’s often because their lungs fail.  Smoking is obviously a major risk factor for dying of Covid-19 – a significant portion of reported Covid-19 deaths could be considered cigarette deaths instead.  Or as air pollution deaths – and yet, our current president is using this crisis as an opportunity to weaken EPA air quality regulations.

Air pollution is a huge problem for a lot of Black communities in the United States.  Our racist housing policies have placed a lot of minority neighborhoods near heavily polluting factories.  Now Covid-19 is turning what is already a lifelong struggle for breath into a death sentence.

I would enthusiastically support a shutdown motivated by the battle for clean air.

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So, Covid-19.  We know how many people have died – already (CORRECTION AS OF APRIL 21) forty-two thousand in the United States

But if we want to know how scary this virus is, we need to know how many people were infected.  If that many people died after everyone in the country had it, then Covid-19 would be less dangerous than influenza.  If that many people died after only a hundred thousand had been infected, then this would be terrifying, and far more dangerous than influenza.

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Initially, our data came from PCR testing.

These are good tests.  Polymerase chain reaction is highly specific.  If you want to amplify a certain genetic sequence, you can design short DNA primers that will bind only to that sequence.  Put the whole mess in a thermocycler and you get a bunch of your target, as long as the gene is present in the test tube in the first place.  If the gene isn’t there, you’ll get nothing.

PCR works great.  Even our lovely but amnesiac lab tech never once screwed it up.

So, do the PCR test and you’ll know whether a certain gene is present in your test tube.  Target a viral gene and you’ll know whether the virus is present in your test tube.  Scoop out some nose glop from somebody to put into the test tube and you’ll know whether the virus is present in that nose glop.

The PCR test is a great test that measures whether someone is actively shedding virus.  It answers, is there virus present in the nose glop?

This is not the same question as, has this person ever been infected with Covid-19? 

It’s a similar question – most people infected with a coronavirus will have at least a brief period of viral shedding – but it’s a much more specific question.  When a healthy person is infected with a coronavirus, the period of viral shedding can be as short as a single day.

A person can get infected with a coronavirus, and if you do the PCR test either before or after that single day, the PCR test will give a negative result.  Nope, no viral RNA is in this nose glop!

And so we know that the PCR test will undercount the true number of infections.

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When we look at the age demographics for Covid-19 infections as measured by PCR test, the undercount becomes glaringly obvious.

Consider the PCR test data from the Diamond Princess cruise ship.  To date, this is our most complete set of PCR data – everyone on board was tested multiple times.  And from this data, it appears that very few children were exposed to the virus.

Friends, it is exceedingly unlikely that such a low percentage of children were exposed to this virus.  Children are disgusting.  I believe this is common knowledge.  Parents of small children are pretty much always sick because children are so disgusting. 

Seriously, my family has been doing the whole “social distancing” thing for over a month, and yet my nose is dripping while I type this.

Children are always touching everything, and then they rub their eyeballs or chew on their fingers.  If you take them someplace, they grubble around on the floor.  They pick up discarded tissues and ask, “What’s this?”

“That’s somebody’s gross kleenex, is what it is!  Just, just drop it.  I know it’s trash, I know we’re not supposed to leave trash on the ground, but just, just drop it, okay?  Somebody will come throw it away later.”

The next day: “Dad, you said somebody would throw that kleenex away, but it’s still there!”

Bloody hell.  Children are little monsters.

It seems fairly obvious that at least as high a percentage of children would be infected as any other age demographic.

But they’re not showing up from the PCR data.  On the Diamond Princess cruise ship, the lockdown began on February 5th, but PCR testing didn’t begin until February 11th.  Anyone who was infected but quickly recovered will be invisible to that PCR test.  And even people who are actively shedding viral particles can feel totally well.  People can get infected and recover without noticing a thing.

We see the same thing when we look at the PCR data from Italy.  If we mistakenly assumed that the PCR data was measuring the number of infections, and not measuring the number of people who were given a PCR test while shedding viral particles, we’d conclude that elderly people went out and socialized widely, getting each other sick, and only occasionally infected their great-grandchildren at home.

Here in the United States, children are disgusting little monsters.  I bet kids are disgusting in Italy, too.  They’re disgusting all over the world.

A much more likely scenario is that children spread this virus at school.  Many probably felt totally fine; some might’ve had a bad fever or the sniffles for a few days.  But then they recovered.

When they got their great-grandparents sick – which can happen easily since so many Italian families live in multigenerational homes – elderly people began to die.

So we know that the PCR test is undercounting the true number of infections.  Unless you’re testing every person, every day, regardless of whether or not they have symptoms, you’re going to undercount the number of infections.

In a moment, we can work through a way to get a more accurate count.  But perhaps it’s worth mentioning that, for someone my age, Covid-19 would seem to be about as dangerous as influenza even if we assumed that the PCR data matched the true number of infections.

If you’re a healthy middle-aged or young person, you should not feel personally afraid. 

That alone would not be an excuse to go out and start dancing in the street, though.  Your actions might cause other people to die. 

(NOTE & CORRECTION: After this post went up, my father recommended that I add something more about personal risk. No one has collected enough data on this yet, but he suspects that the next most important risk factor, after smoking and age, will be type 2 diabetes. And he reminded me that many people in their 30s & 40s in this country are diabetic or prediabetic and don’t even realize it yet. Everyone in this category probably has elevated risk of complications from Covid-19.)

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After you’ve been infected with a virus, your body will start making antibodies.  These protect you from being infected again.

Have you read Shel Silverstein’s Missing Piece book?  Antibodies work kind of like that.  They have a particular shape, and so they’ll glom onto a virus only if that virus has outcroppings that match the antibody’s shape.  Then your body sees the antibodies hanging out on a virus like a GPS tracker and proceeds to destroy the virus.

So to make an antibody test, you take some stuff that looks like the outcroppings on the virus and you put it on a chip.  Wash somebody’s blood over it, and if that blood contains antibodies that have the right shape to glom onto the virus, they’ll stick to the chip.  All your other antibodies, the ones that recognize different viruses, will float away.

An antibody test is going to be worse than a PCR test.  It’s easier to get a false positive result – antibodies are made of proteins, and they can unfold if you treat them roughly, and then they’ll stick to anything.  Then you’ll think that somebody has the right antibodies, but they don’t.  That’s bad.

You have to be much more careful when you’re doing an antibody test. I wouldn’t have asked our lab tech to do them for me.

An antibody test is also going to have false negatives.  A viral particle is a big honking thing, and there are lots of places on its surface where an antibody might bind.  If your antibodies recognize some aspect of the virus that’s different from what the test manufacturers included on their chip, your antibodies will float away.  Even though they’d protect you from the actual virus if you happened to be exposed to it.

If you’re a cautious person, though – and I consider myself to be pretty cautious – you’d much rather have an antibody test with a bunch of false negatives than false positives.  If you’re actually immune to Covid-19 but keep being cautious, well, so what?  You’re safe either way.  But if you think you’re immune when you’re not, then you might get sick.  That’s bad.

Because antibody tests are designed to give more false negatives than false positives, you should know that it’d be really foolish to use them to track an infection.  Like, if you’re testing people to see who is safe to work as a delivery person today, use the PCR test!  The antibody test has a bunch of false negatives, and there’s a time lag between the onset of infection and when your body will start making antibodies.

It can be dangerous to use antibody tests to address the wrong questions.

If you use the antibody test on a bunch of people, though, you can tell how many were infected.  And that’s useful information, too.

In the town of Robbio in Italy (pop. 6,000), the PCR test showed that only 23 people had been infected with Covid-19.  But then the mayor implored everyone to get an antibody test, and 10% of people had actually been infected with – and had recovered from – Covid-19.  Most of them couldn’t even recall having been sick.

The PCR test measured 23 cases.  The antibody test suggested there’d been at least 600.  And antibody tests, by design, will generally have a bunch of false negatives.  When a team at Stanford assessed the antibody tests manufactured by Premier Biotech in Minneapolis, they found that for every 3 people who’d been infected with Covid-19, the tests registered only 2 positives.

I don’t know who made the tests used in Robbio – maybe they were a little better, maybe they were a little worse.  Based on my experience, I wouldn’t be so surprised if the true infection rate with Covid-19 in that town was really just 10% – nor would I be surprised to hear that the chips had a high false-negative rate and that the infection rate was 20% or more.

If you calculate the fatality rate of Covid-19 in Italy by assuming that the PCR tests caught every infection, you’d get a terrifying 10%.

If you instead assume that many other towns had a similar infection rate to Robbio, you’ll instead calculate that the fatality rate was well under one percent. 

Italy has higher risk than the United States due to age demographics, smoking rates, and multigenerational households – and even in Italy, the fatality rate was probably well under one percent.

When researchers in Germany randomly chose people to take a Covid-19 PCR test (many of whom had no symptoms), they found that 2% of the population was actively shedding virus – a much higher number of cases than they would have found if they tested only sick people.  And when they randomly chose people to take an antibody test, they found that 15% had already recovered from the infection (again, many of whom had never felt sick).  According to these numbers – which are expected to be an undercount, due to false negatives and the time lag before antibody production – they calculated a case fatality rate of 0.37%

That would be about three-fold more dangerous than seasonal influenza.

In the United States, our bungling president gutted the CDC, leaving us without the expertise needed to address Covid-19 (or myriad other problems that might arise).  During the first few months of this epidemic, very few people managed to get a PCR test.  That’s why our data from the PCR tests is likely to be a dramatic undercount – indeed, when we finally started producing accurate tests, the apparent growth in Covid-19 caseload superimposed with the growth in test availability.

In the absence of good PCR data, we have to rely on antibody data to track infections after the fact.  Which is why a town in Colorado with zero reported infections, as measured by PCR, had sufficiently widespread exposure that 2% of the population had already recovered from Covid-19.

And it’s why the data from the Stanford Santa Clara county study is so unsurprising. 

Yes, there were problems with the Stanford study’s data collection – they displayed advertisements to a random selection of people, but then a self-selected subset responded.  The pool of respondents were enriched for white women, but Santa Clara’s outbreak probably began among Asian-Americans.  And we all know that random sampling doesn’t always give you an accurate depiction of the population at large – after all, random polling predicted that a competent president would be elected in 2016.

Now look at us.

It’s also likely that people with a poor understanding of the biology could misinterpret the result of the Stanford study.  They found that PCR tests had undercounted the infection rate in Santa Clara county, at the time of this study, by 85-fold.

It would be absurd to assume that you could simply multiply all PCR results by 85 to determine the true infection rate, but some people did.  And then pointed out the absurdity of their own bad math.

In places where more people are being tested by PCR, and they’re being tested more often, the PCR results will be closer to the true infection rate.  If you gave everyone in the United States a PCR test, and did it every day, then the PCR data would be exactly equal to the true infection rate.

If we had data like that from the beginning, we wouldn’t have been scared.  We would’ve known the true case fatality rate early on, and, also, at-risk people could’ve been treated as soon as they got infected.  We’d be able to save many more lives.

If access to health care were considered a basic right in the United States, we might’ve done something like this. 

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In Italy, it seems like Covid-19 is three- or four-fold more dangerous than seasonal influenza.  My guess is that Italy might have had about 50,000 deaths if they hadn’t enacted the lockdown.

In the United States, on a population level, Covid-19 is probably also more dangerous than seasonal influenza.  But there’s a big difference in terms of the distribution of risk.

The New York Times is running a series with short biographies of people who’ve died of Covid-19.  As of noon on April 17, about 10% of the people profiled were younger than 35.

10% is roughly the proportion of young people who die of seasonal influenza.  But only 1% of Covid-19 deaths are people younger than 35.  The news reports don’t always make clear how much the risk of Covid-19 is clustered in a small segment of the population.

This has serious implications for what we should do next.  If we were dealing with a virus that was about three-fold more dangerous than seasonal influenza for everyone, we might just return to life as normal.  (Indeed, we carried on as normal during the bad years when seasonal influenza killed 90,000 people instead of last year’s 30,000.)

Because the risk from Covid-19 is so concentrated, though, we can come up with a plan that will save a lot of lives. 

Healthy people under retirement age should resume most parts of their lives as normal.  Schools should re-open: for students, Covid-19 is much less dangerous than seasonal influenza.  I think that people should still try to work from home when possible, because it’s the right thing to do to fight climate change.

At-risk people should continue to isolate themselves as much as possible.

This sounds crummy, but at-risk people would just continue to do the thing that everyone is doing currently.  And the plan would save many lives because the epidemic would end in about 3 months, after the virus had spread to saturation among our nation’s low-risk cohort. 

Indeed, when a team of researchers from Harvard’s School of Public Health modeled the Covid-19 epidemic, they found that social distancing was generally unhelpful.  That’s what their data show, at least – but in their abstract, they instead recommend that we continue social distancing for the better part of two years.

Their data are easy enough to understand.  In each of these graphs, they show a blue box for how long social distancing would last, and then four colored lines to represent how many infections we’d see if we did no social distancing (black), medium quality social distancing (red), good social distancing (blue), or excellent social distancing (green).

So, from top to bottom, you’re looking at the graphs of what happens if we do a month of social distancing … or two months … or three, or four … or forever.

And you can see the outcomes in the panels on the right-hand side.  The black line shows what would happen if we did nothing.  Infections rise fast, then level off after the virus has reached saturation.  There are two important features of this graph – the final height that it reaches, which is the total number of severe cases (and so a good proxy for the number of deaths), and the slope of the line, which is how fast the severe cases appear.  A steeper hill means many people getting sick at the same time, which means hospitals might be overwhelmed.

So, okay.  Looking at their graphs, we see that social distancing saves lives … if we do it forever.  If you never leave your house again, you won’t die of Covid-19.

But if social distancing ends, it doesn’t help.  The slopes are nearly as steep as if we’d done nothing, and the final height – the total number of people who die – is higher.

(Often, one of their curves will have a gentler slope than the others — usually the good-but-not-excellent social distancing seems best. So you’d have to pray that you were doing a precisely mediocre job of not infecting strangers. Do it a little better or a little worse and you cause people to die. This isn’t an artifact — it’s based on the density of uninfected people when social distancing ends — but let’s just say “mathematical models are wonky” and leave it at that.)

In a subsequent figure, the Harvard team tried to model what might happen if we occasionally resumed our lives for a month or so at a time, but then had another shutdown.  This is the only scenario in which their model predicts that social distancing would be helpful.

But, unfortunately, there’s a problem.  Research done with other coronaviruses shows that immunity fades within a year.  Because the Harvard model would cause the epidemic to last longer than a year, people would have time to lose their immunity and get infected again.

Even in the extreme case that we mostly stayed in our homes for the better part of two years, social distancing would case more deaths from Covid-19 than if we had done nothing.

That’s not even accounting for all the people who would die from a greater risk of domestic violence, hunger, drug addiction, suicide, and sedentary behavior during the shutdown.  

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When our data was limited, the shutdown seemed reasonable.  We wouldn’t be able to undo the damage we’d done by waiting.

Except, whoops, we waited anyway.  We didn’t quarantine travelers in January.  The shutdown didn’t begin March, when the epidemic was well underway in many places. 

Now that we have more data, we should re-open schools, though.  For most people, Covid-19 is no more dangerous than seasonal influenza.  We already have enough data from antibody testing to be pretty confident about this, and even if we want to be extremely cautious, we should continue the shutdown for a matter of weeks while we conduct a few more antibody studies.  Not months, and certainly not years.

At the same time, we need to do a better job of protecting at-risk people.  This means providing health care for everyone.  This means cleaning our air, staunching the pollution that plagues low-income neighborhoods.  This might mean daily medical checkups and PCR tests for people who work closely with at-risk populations.

Our country will have to be different in the future, but mostly because we, as a people, have done such a shitty job of creating justice and liberty for all.  We need to focus on addressing the inequities that we’ve let fester for generations.  That’ll help far more than using a bandanna to cover up your smile.

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UPDATE: Wow, this got a lot of readers! Thanks if you made it this far. I’ve also written a response to common questions and comments about this essay.