Category: Medicine

The course of Covid-19 in the United States

Via Amihai Glazer.  And if you wish to verify, here is another (non-smoothed) presentation of the data.

In terms of the delta this picture is not as bad as what you sometimes hear, though data on cases are far worse, with a very long and indeed continuing plateau. And since deaths lag cases by a few weeks, you still might see reason to be alarmed.  Nonetheless, the trend we can see is one of improvement, at least for a little over two months.

Do note it is better for everyone if you think the death rate is still rising!

Coronavirus travel markets in everything

As tourism slowly resumes around the world, many nations are still reluctant to open their borders fully – with Cambodia imposing perhaps the toughest entry requirements of any country.

The south-east Asian country is popular with backpackers, and most renowned for the Unesco-listed temple complex at Angkor Wat.

According to the latest Foreign Office bulletin on Cambodia, foreign travellers must pay a $3,000 (£2,400) deposit for “Covid-19 service charges” at the airport upon arrival.

What appears to be the first “coronavirus deposit” can be paid in cash or by credit card.

The FCO says: “Once deductions for services have been made, the remainder of the deposit will be returned.” But those deductions may be steep – especially if another passenger on the same flight happens to test positive for coronavirus.

So far, so good, perhaps you are keen to go.  But here is the downside of the experience:

But if one passenger on their flight tests positive for coronavirus, everyone on the same flight is quarantined in government-approved accommodation for two weeks, at a cost of $1,176 including meals, laundry and “sanitary services”. They must also pay another $100 for a second Covid-19 test. This totals a further £1,021.

If the traveller happens to be the coronavirus-positive patient, they will have to take up to four tests at another $100 (£80) each, as well as $3,150 (£2,500) for treatment at the Khmer-Soviet Friendship Hospital in the capital, Phnom Penh.


…Cambodia also imposes a requirement for $50,000 (£40,000) of travel insurance cover for medical treatment.

If the unfortunate arrival passes away, the Foreign Office warns: “The cremation service charge is $1,500 [£1,200].”

Here is the full article, via Shaffin Shariff.

Database of 1,100 superspreading events

It is about time someone put this together, here are some summary conclusions:

  • Nearly all SSEs in the database — more than 97% — took place indoors
  • The great majority of SSEs happened during flu season in that location
  • The vast majority took place in settings where people were essentially confined together, indoors, for a prolonged period (for example, nursing homes, prisons, cruise ships, worker housing)
  • Processing plants where temperatures are kept very low (especially meat processing plants) seem particularly vulnerable to SSEs

Here is the full material by Koen Swinkels, via Balaji.

Why non-distanced social and commercial interactions have resumed so quickly

People have solved for the equilibrium.

First, the socially-distanced goods, such as food delivery, are starting to rise in price.  The non-distanced goods have been falling in relative price, and so now people are moving along their demand curves and engaging in less distancing.

Second, the longer the pandemic will run, the harder it is to use intertemporal substitution as a “make up.”  “I won’t go to a bar for two months, but then I’ll go a lot to make up for it” is a plausible story to tell oneself.  “I won’t go to a bar for a year and then I’ll go a lot…” is harder to swallow and act upon.  It starts to become a habit, and at some point you can’t drink enough to make up for what you have lost.  And so people are more inclined to go to the bar right now.

Most importantly, peer effects are remarkably strong.  Most people are not willing to accept a small additional risk of death to say eat in a particular restaurant.  But they are willing to accept a small additional risk of death to live life as other people are living life.

So once enough people are not respecting social distancing, most of the others will follow.

Some wag on Twitter said we can no longer use the expression “to avoid like the plague,” because apparently people do not take so much care to avoid the plague.

Implications of Heterogeneous SIR Models for Analyses of COVID-19

This paper provides a quick survey of results on the classic SIR model and variants allowing for heterogeneity in contact rates. It notes that calibrating the classic model to data generated by a heterogeneous model can lead to forecasts that are biased in several ways and to understatement of the forecast uncertainty. Among the biases are that we may underestimate how quickly herd immunity might be reached, underestimate differences across regions, and have biased estimates of the impact of endogenous and policy-driven social distancing.

That is the abstract of a new paper by Glenn Ellison, recommended.

Political and social correlates of Covid-19 mortality

Do political and social features of states help explain the evolving distribution of reported Covid-19 deaths? We identify national-level political and social characteristics that past research suggests may help explain variation in a society’s ability to respond to adverse shocks. We highlight four sets of arguments—focusing on (1) state capacity, (2) political institutions, (3) political priorities, and (4) social structures—and report on their evolving association with cumulative Covid-19 deaths. After accounting for a simple set of Lasso-chosen controls, we find that measures of government effectiveness, interpersonal and institutional trust, bureaucratic corruption and ethnic fragmentation are currently associated in theory-consistent directions. We do not, however, find associations between deaths and many other political and social variables that have received attention in public discussions, such as populist governments or women-led governments. Currently, the results suggest that state capacity is more important for explaining Covid-19 mortality than government responsiveness, with potential implications for how the disease progresses in high-income versus low-income countries. These patterns may change over time with the evolution of the pandemic, however. A dashboard with daily updates, extensions, and code is provided at

That is from a new paper by Constantin Manuel Bosancianu,, via Alex Scacco.

China-U.S. fact of the day

Some 54 scientists have resigned or been fired as a result of an ongoing investigation by the National Institutes of Health into the failure of NIH grantees to disclose financial ties to foreign governments. In 93% of those cases, the hidden funding came from a Chinese institution.

The new numbers come from Michael Lauer, NIH’s head of extramural research. Lauer had previously provided some information on the scope of NIH’s investigation, which had targeted 189 scientists at 87 institutions. But his presentation today to a senior advisory panel offered by far the most detailed breakout of an effort NIH launched in August 2018 that has roiled the U.S. biomedical community, and resulted in criminal charges against some prominent researchers, including Charles Lieber, chair of Harvard University’s department of chemistry and chemical biology.

“It’s not what we had hoped, and it’s not a fun task,” NIH Director Francis Collins said in characterizing the ongoing investigation. He called the data “sobering.”

Here is the full story, and there are further points of interest at the link.

A new study of face masks

We use the synthetic control method to analyze the effect of face masks on the spread of Covid-19 in Germany. Our identification approach exploits regional variation in the point in time when face masks became compulsory. Depending on the region we analyse, we find that face masks reduced the cumulative number of registered Covid-19 cases between 2.3% and 13% over a period of 10 days after they became compulsory. Assessing the credibility of the various estimates, we conclude that face masks reduce the daily growth rate of reported infections by around 40%.

That is from a new paper by Timo Mitze, Reinhold Kosfeld, Johannes Rode, and Klaus Wälde.

Rescheduling for thee, but not for me

When Wisconsin Republicans refused to move their election day, Democrats, experts, and various media types decried the decision as immoral and dangerous during a pandemic. “Regularly scheduled, orderly elections with direct governmental consequences were either too dangerous, or insufficiently compelling,” Adam wrote in a late-night email. “Contrast that, of course, with Democrats’s evident belief that we absolutely must not delay these protests against police brutality. The protests—spontaneous not scheduled, disorderly not orderly, emotive not concretely consequential—simply had to go on.”

Protests and demonstrations are more important and indispensable than elections. The deliberate act of voting, essential to a democracy, can be put on a schedule delay but political catharsis must proceed on its own schedule. Mario Cuomo used to say that “We campaign in poetry but we govern in prose.” Now it’s poetry or nothing.

Here is more by Jonah Goldberg.  I am not looking to attack or make trouble for any individual person here, so no link or name, but this is from a leading figure in biology and also a regular commenter on epidemiology:

As a citizen, I wholeheartedly support the protests nonetheless.

My worries run deep.  Should the original lockdown recommendations have been asterisked with a “this is my lesser, non-citizen self speaking” disclaimer?  Should those who broke the earlier lockdowns, to save their jobs or visit their relatives, or go to their churches, or they wanted to see their dying grandma but couldn’t…have been able to cite their role as “citizens” as good reason for opposing the recommendations of the “scientists”?  Does the author have much scientific expertise in how likely these protests are to prove successful?  Does typing the word “c-i-t-i-z-e-n” relieve one of the burden of estimating how much public health credibility will be lost if/when we are told that another lockdown is needed to forestall a really quite possible second wave?  Does the author have a deep understanding of the actual literature on the “science/citizen” distinction, value freedom in science, the normative role of the advisor, and so on?  Does the implicit portrait painted by that tweet imply a radically desiccated, and indeed segregated role of the notions of “scientist” and “citizen”?  Would you trust a scientist like that for advice?  Should you?  And shouldn’t he endorse the protests “2/3 heartedly” or so, rather than “wholeheartedly”?  Isn’t that the mood affiliation talking?

On May 20th, the same source called a Trump plan for rapid reopening (churches too, and much more) “extraordinarily dangerous” — was that the scientist or the citizen talking?  And were we told which at the time?  Andreas’s comments at that above link are exactly on the mark, especially the point that the fragile consensus for the acceptability of lockdown will be difficult to recreate ever again.

If you would like a different perspective, bravo to Dan Diamond.  Here is his article.  And here are some better options for public health experts.  Here is a useful (very rough) estimate of expected fatalities from the protests, though it does not take all-important demonstration effects into account.  I can say I give credit to the initial source (the one I am criticizing) for passing that tweet storm along.

We really very drastically need to raise the quality and credibility of the advice given here.

Solve for the equilibrium

What might be some alternate (if possibly slightly unfair) titles?  How about

“A Swede by Any Other Name” or “America > Sweden”?

“Refuting Friedman-Savage, convexity all over”

“Their capitalist bosses made them turn out”

“They all supported lockdown in the poll”

What else?


Our regulatory state is broken, installment #1837

Americans returning from China landed at U.S. airports by the thousands in early February, potential carriers of a deadly virus who had been diverted to a handful of cities for screening by the Centers for Disease Control and Prevention.

Their arrival prompted a frantic scramble by local and state officials to press the travelers to self-quarantine, and to monitor whether anyone fell ill. It was one of the earliest tests of whether the public health system in the United States could contain the contagion.

But the effort was frustrated as the C.D.C.’s decades-old notification system delivered information collected at the airports that was riddled with duplicative records, bad phone numbers and incomplete addresses. For weeks, officials tried to track passengers using lists sent by the C.D.C., scouring information about each flight in separate spreadsheets.

“It was insane,” said Dr. Sharon Balter, a director at the Los Angeles County Department of Public Health. When the system went offline in mid-February, briefly halting the flow of passenger data, local officials listened in disbelief on a conference call as the C.D.C. responded to the possibility that infected travelers might slip away.

“Just let them go,” two of the health officials recall being told.

Here is the full NYT piece, thorough, excellent, and scary throughout, and it shows a first-rate understanding of bureaucracy.  Don’t forget the CDC budget has risen steadily in real terms.

Karl Friston on “immunological dark matter”

We’ve been comparing the UK and Germany to try to explain the comparatively low fatality rates in Germany. The answers are sometimes counterintuitive. For example, it looks as if the low German fatality rate is not due to their superior testing capacity, but rather to the fact that the average German is less likely to get infected and die than the average Brit. Why? There are various possible explanations, but one that looks increasingly likely is that Germany has more immunological “dark matter” – people who are impervious to infection, perhaps because they are geographically isolated or have some kind of natural resistance. This is like dark matter in the universe: we can’t see it, but we know it must be there to account for what we can see. Knowing it exists is useful for our preparations for any second wave, because it suggests that targeted testing of those at high risk of exposure to Covid-19 might be a better approach than non-selective testing of the whole population.

Speculative, and here is the full article, mostly about other matters epidemiological.  Via Michelle Dawson.

The contents of this article may well be wrong, as many on Twitter are suggesting, that link makes two renowned researchers/commentators or here is Kai Kupferschmidt.  I am less impressed by passing potshots at the author and more interested in reading a short blog post.  I say write out 500 words (with links) comparing different methods of accounting for the unexplained residuals and heterogeneities with Covid-19 (not it is not all policy, and how much of it is sheer luck and/or timing?).  Also discuss the circulating notion that previous exposure to (some) other coronaviruses, or perhaps weak doses of Covid-19, might be giving some individuals partial immunity (an idea being batted around but not verified as far as I know.  And what do we know about how much geographic isolation might matter (a concept cited by Friston in contradistinction to the Twitter claims that he is simply talking about ghosts)?  Then tweet the post, you still can start a blog for free and write just a single post, more over time if you wish.  I would very gladly link to it.