Bad intuitions about masking: Japan, 1933

Reading the gripping recent book by Uwe Wittstock on the activities of German writers and artists in the shock of February 1933, I just came across this passage from the little-known writer Hans Michaelis, published in the Berliner Morgenpost, reported from Japan on a medical innovation against the dangerous wave of flu then circling the globe:

„Die Bazillenmaske: Ein Oval-geschnittenes schwarzes Stück Tuch wird vor Mund und Nase gebunden, und hat die schwere Aufgabe den Bazillen den Eintritt zu verwehren.“ Allerdings wird die Mund-Nase-Maske, zur Überraschung von Michaelis, nur unter freiem Himmel getragen. In der Bahn und im Büro setzen die Japaner die Maske ab. “Sie sind der Überzeugung, dass sich die Grippeerreger vor allem auf der Strasse verbreiten, nicht in geschlossenen Räumen.”

“The bacteria-mask: An oval of black cloth is tied in front of the mouth and nose, and has the challenging task of denying entry to any and all bacteria.To be sure, these nose-and-mouth masks are only worn outdoors, much to Michaelis’s surprise. In the train and in the office the Japanese take the masks off. They are convinced that the flu germs spread mainly on the street, not in enclosed spaces.

Several things stand out about this report: First, how strange it is to see the hygienic mask as a new piece of technology. Particularly since we‘ve now all seen photographs from the US from the 1918-19 flu pandemic. It‘s not clear to me what was known when about the usefulness of medical masks.

Second, it‘s interesting to see innovations from Japan being taken so seriously, by an early 20th century European.

Third, when I visited Japan in 2005 I was interested to see so many people wearing masks on the street. I attributed this to the recent experience of SARS, but possibly the affinity for medical masks goes back much further.

Finally, there is this restriction of masks to outdoors, exactly the opposite of what we learned to do with COVID. I wonder if there was some misconceived medical theory behind this, or if it was simply the common intuition that one is safe indoors. Seeing public transport as “safe” in that way seems very strange, though.

More metric-imperial conversion hijinks

A while back I noted how an article on Ebola in the NY Times had apparently translated “one millilitre of blood” in a medical context into “one-fifth of a teaspoon of blood”. Hilarity ensued. Now I see that the fun doesn’t go in only one direction. I just got a letter from the NHS about an upcoming appointment, including these instructions:

Do not come to your appointment if you or anyone living with you has the symptoms of a new continuous cough (in the last week) or a temperature above 37.8 degrees or loss or change to your sense of smell or taste.

37.8 degrees? Why exactly this number? It sounds both arbitrary and absurdly precise. A bit of reflection revealed that 37.8 degrees Celsius is precisely 100 degrees Fahrenheit. They obviously copied some American guidelines, and instead of rounding appropriately — or reconsidering the chosen level — they just calculated the corresponding Celsius temperature. The funny thing is, Americans are used to having the very non-round guideline of 98.6 degrees as the supposed “normal” body temperature, because someone* in the 19th Century decided 37 degrees Celsius was roughly the right number, and that magic number got translated precisely into Fahrenheit.

* Carl Reinhold August Wunderlich, actually.

Suicides at universities, and elsewhere

The Guardian is reporting on the inquest results concerning the death by suicide of a physics student at Exeter University in 2021. Some details sound deeply disturbing, particularly the account of his family contacting the university “wellbeing team” to tell them about his problematic mental state, after poor exam results a few months earlier (about which he had also written to his personal tutor), but

that a welfare consultant pressed the “wrong” button on the computer system and accidentally closed the case. “I’d never phoned up before,” said Alice Armstrong Evans. “I thought they would take more notice. It never crossed my mind someone would lose the information.” She rang back about a week later but again the case was apparently accidentally closed.

Clearly this university has structural problems with the way it cares for student mental health. I’m inclined, though, to focus on the statistics, and the way they are used in the reporting to point at broader story. At Exeter, we are told, there have been (according to the deceased student’s mother) 11 suicides in the past 6 years. The university responds that “not all of the 11 deaths have been confirmed as suicides by a coroner,” and the head of physics and astronomy said “staff had tried to help Armstrong Evans and that he did not believe more suicides happened at Exeter than at other universities.”

This all sounds very defensive. But the article just leaves these statements there as duelling opinions, whereas some of the university’s claims are assertions of fact, which the journalists could have checked objectively. In particular, what about the claim that no more suicides happen at Exeter than at other universities?

While suicide rates for specific universities are not easily accessible, we do have national suicide rates broken down by age and gender (separately). Nationally, we see from ONS statistics that suicide rates have been roughly constant over the past 20 years, and that there were 11 suicides per 100,000 population in Britain in 2021. That is, 16/100,000 among men and 5.5/100,000 among women. In the relevant 20-24 age group the rate was also 11. Averaged over the previous 6 years the suicide rate in this age group was 9.9/100,000; if the gender ratio was the same, then we get 14.4/100,000 men and 5.0/100,000 women.

According to the Higher Education Statistics Agency, the total number of person years of students between the 2015/2016 and 2020/2021 academic years were 81,795 female, 69,080 male, and 210 other. This yields a prediction of around 14.5 deaths by suicide in a comparable age group over a comparable time period. Thus, if the number 11 in six years is correct, it is still fewer deaths by suicide at the University of Exeter than in comparable random sample of the rest of the population.

It’s not that this young man’s family should be content that this is just one of those things that happens. There was a system in place that should have protected him, and it failed. Students are under a lot of stress, and need support. But non-students are also under a lot of stress, and also need support. It’s not that the students are being pampered. They definitely should have institutionalised well-trained and sympathetic personnel they can turn to in a crisis. Where where are the “personal tutors” for the 20-year-olds who aren’t studying, but who are struggling with their jobs, or their families, or just the daily grind of living? And what about the people in their 40s and 50s, whose suicide rates are 50% higher than those of younger people?

Again, it would be a standard conservative response to say, We don’t get that support, so no one should get it. Suck it up! A more compassionate response is to say, students obviously benefit from this support, so let’s make sure it’s delivered as effectively as possible. And then let’s think about how to ensure that everyone who needs it gets helped through their crises.

Is Covid hacking people’s brains?

The single-celled parasite toxoplasma gondii is known to structurally change the brains of infected mice to cause them to lose their fear of cats. This transformation aids the fitness of the pathogen essential for the pathogen to complete its life cycle, because it can reproduce sexually only in cat guts. The fungus Ophiocordyceps unilateralis infects carpenter ants, and then

it grows through the insect’s body, draining it of nutrients and hijacking its mind. Over the course of a week, it compels the ant to leave the safety of its nest and ascend a nearby plant stem. It stops the ant at a height of 25 centimeters—a zone with precisely the right temperature and humidity for the fungus to grow. It forces the ant to permanently lock its mandibles around a leaf. Eventually, it sends a long stalk through the ant’s head, growing into a bulbous capsule full of spores. And because the ant typically climbs a leaf that overhangs its colony’s foraging trails, the fungal spores rain down onto its sisters below, zombifying them in turn.

The rabies virus is well known to induce aggression in its hosts, leading them to bite others and so transmit the virus in its saliva.

Is any of this relevant to humans? Toxoplasma infection is found in around 30% of UK residents — acquired from contact with pet cats — and there is evidence that it may contribute to schizophrenia. There is strong evidence that prenatal maternal infection raises the risk of the child going on to develop schizophrenia. But this is presumably just a byproduct of the essential neuropathogenicity that promoted the pathogen’s fitness in mice.

I was thinking of this, though, when I saw this new study:

Executive dysfunction following SARS-CoV-2 infection: A cross-sectional examination in a population-representative sample

People who had previously suffered a Covid infection “reported a significantly higher number of symptoms of executive dysfunction than their non-infected counterparts”. Executive dysfunction, according to Wikipedia, is “a disruption to the efficacy of the executive functions, which is a group of cognitive processes that regulate, control, and manage other cognitive processes… Executive processes are integral to higher brain function, particularly in the areas of goal formation, planning, goal-directed action, self-monitoring, attention, response inhibition, and coordination of complex cognition.”

Perhaps coincidentally, we have seen, since the start of the pandemic, an upsurge of seemingly inexplicable emotionally overwrought rejection of measures that might prevent the individual from spreading the virus, or from catching it again oneself, especially masking and vaccination. Could it be that this is itself a neurological sequela of a Covid infection, that manipulates the sufferer’s brain, like the carpenter ant’s, to maximise the spread to conspecifics? Or that, like a hacker “backdooring” a compromised system, the virus has evolved to make its host pliable to future infection, once the immune response has waned?

I’m just asking questions.

Booster — the final report

Another update of my Covid booster saga. After the only walk-in vaccination centre in Oxford decided to stop accepting walk-ins I looked about for other options. I was now eligible for a booster, but couldn’t sign up for an appointment, because only NHS-delivered vaccines count. I considered getting an appointment for a nominal first vaccine, but worried that that might just get me into trouble. I heard that the NHS had suddenly decided to start registering vaccinations performed abroad, and that would allow me to get a booster. (The website even suggested that you may be given a booster vaccine at the appointment, but you may not, and the appointment is really only to register your information.) But, bizarrely, the registration has to be done in person, and the nearest place is Reading, 25 miles away. So I could take the train, possibly get infected on the way, in order to get a booster.

Instead, I saw that there was a pharmacy offering drop-in vaccinations in Aylesbury, about 17 miles from Oxford, and connected by a reasonable route for cycling. And they were open Sunday. The weather was good, so I set out a bit after 8 on my bicycle, arriving around 9:45, shortly after they opened at 9:30.

“Do you have an appointment?”
“No. I’m here for a walk-in.”
Funny look.
“This is listed on the NHS website as a walk-in site.”
“It was, until yesterday, when we ran out of vaccine.”
“I just cycled two hours from Oxford.”
“If you want you can wait in that queue over there and try your luck.”
There were about a dozen people waiting already. I ended up being the last walk-in they let in, and I got the booster.

A student of mine waited 6 hours in the rain yesterday for a booster. I remember a German colleague commenting many years ago that he liked American university libraries because the librarians consider it their job to serve the readers with books. Unlike German librarians who consider it their job to protect the books from the readers.

The NHS — meaning, the larger dysfunctional system of the NHS and its many private subcontractors — seems to have a similar attitude toward vaccines. Better that ten should go unvaccinated than that one ineligible person should be vaccinated.

No booster [update 10-12-2021]

The UK government is apparently desperately eager to get the whole population fully protected with three doses of Covid vaccine, to try and head off the mounting omicron wave. In a particularly awkward mixed pharmaceutical metaphor they promised to put the programme “on steroids”. But not so eager that they’re willing to resort to extreme measures like… just letting people get vaccinated.

The NHS website says people will be contacted for appointments six months after their second dose. But the government announced more than a week ago, following new advice from the Joint Committee on Vaccinations and Immunisations (JCVI), that “the booster will now be given no sooner than 3 months after the primary course.”

Having been initially vaccinated in Germany I can’t get on the list for an appointment anyway, so I decided to cycle down to Kassam Stadium, south of Oxford, the only nearby vaccination centre offering walk-in service. The fellow managing the queue was friendly and helpful, but told me that the current regulation — until they get new rules from the government — is actually a completely arbitrary seeming five months gap for people over 50 years of age (which I haven’t seen reported anywhere) — and six months for people over 40. (And no boosters for younger people.

So, no booster yet for me…

Update (8/12/2021): The NHS has now opened up boosters to people who had their second dose more than 3 months ago. Except, the bad people who had their first doses in foreign lands — including, if I understand correctly, Scotland — are still excluded.

[update 10-12-2021]: Yesterday mid-afternoon the official NHS website for vaccination information reported that anyone over 40 could get a booster at a walk-in site 3 months after their second dose. So I cycled down to Kassam Stadium again this morning. And again I was turned away. This time they agreed that I was eligible according to the NHS rules, but they have their own rules at this centre, and they’re not changing until Monday.

Not that it matters, because they also — my partner found this out when she went in the afternoon — decided spontaneously as of 2pm today to stop accepting walk-ins at all.

The de-wormer turns

Apparently, a conference in Florida to promote the use of anti-parasite treatment Ivermectin for Covid, turned into a super-spreader event.

“I have been on ivermectin for 16 months, my wife and I,” Dr Bruce Boros told the audience at the event held at the World Equestrian Center in Ocala, adding: “I have never felt healthier in my life.”

Boros is now reported to be gravely ill with Covid, and at least six other physicians who attended were also infected. It seems to me, if you don’t want people to dismiss your miracle treatment as “horse de-wormer”, you might choose to hold your national gathering somewhere that is not an equestrian center.

Thinking about exponential growth and “Freedom Day”

The UK government is holding fast to its plan to drop all pandemic restrictions as of 19 July, even in the face of rapidly increasing infection rates, hospitalisation rates, and Covid deaths — all up by 25-40% over last week. And numerous medical experts are being quoted in the press supporting the decision. What’s going on?

To begin with, Johnson has boxed himself in. He promised “Freedom Day” to coincide with the summer solstice, and then was forced to climb down, just as he was from his initial “infect everyone, God will recognise his own” plan last March, on realising that his policies would yield an unsustainable level of disruption. The prime minister has, by now, no reputation for consistency or decisiveness left to protect, but even so he probably feels at the very least that a further delay would undermine his self-image as the nation’s Fun Dad. At the same time, the the new opening has been hollowed out, transformed from the original “Go back to living your lives like in pre-pandemic days” message to “Resume taxable leisure activities, with the onus on individuals and private businesses to enforce infection-minimisation procedures.” Thus we have, just today, the Transport Secretary announcing that he expected rail and bus companies to insist on masking, even while the government was removing the legal requirement.

But what are they hoping to accomplish, other than a slight reduction in the budget deficit? The only formal justification offered is that of Health Secretary Sajid Javid, who said on Monday

that infection rates were likely to get worse before they got better – potentially hitting 100,000 a day – but said the vaccination programme had severely weakened the link between infections, hospitalisations and deaths.
Javid acknowledged the risks of reopening further, but said his message to those calling for delay was: “if not now, then when?”.

“Weakened the link” is an odd way of putting a situation where cases, hospitalisations, and Covid deaths are all growing exponentially at the same rate. What has changed is the gearing, the chain and all of its links is as strong as ever. In light of that exponential growth, what should we make Javid’s awkward channeling of Hillel the Elder?

I’ll talk about “masking” as synecdoche for all measures to reduce the likelihood of a person being infected or transmitting Covid. We need to consider separately the questions of when masking makes sense from an individual perspective, and from a public perspective. The individual perspective is straightforward:

On the societal level it’s more complicated, but I do find the argument of England’s Chief Medical Officer Chris Whitty… baffling:

“The slower we take it, the fewer people will have Covid, the smaller the peak will be, and the smaller the number of people who go into hospital and die,” he said.
By moving slowly, he said modelling suggested the pressure on the NHS would not be “unsustainable”.
Prof Whitty said there was less agreement on the “ideal date” to lift restrictions as there is “no such thing as an ideal date” .
However, he said a further delay would mean opening up when schools return in autumn, or in winter, when the virus has an advantage and hospitals are under more pressure.

We may argue about how much effect government regulations have on the rate of the virus spreading, but I have never before heard anyone argue that the rate of change of government regulation is relevant. Of course, too rapid gyrations in public policy may confuse or anger the public. But how the rapidity of changing the rules relates to the size of the peak seems exceptionally obscure. To the extent that you are able to have any effect with the regulations, that effect should be seen directly in R0, and so in the weekly growth or contraction of Covid cases. If masking can push down the growth rate its effect is essentially equivalent at any time in terms of the final infection rate, but masking early gives fewer total cases.

To see this, consider a very simple model: With masking cases grow 25%/week, without masking they shrink 20%/week. So if we have 1000 cases/day now, then after some weeks of masking and the same number of weeks without masking, we’ll be back to 1000 cases/day at the end. But the total number of cases will be very different. Suppose there are 10 weeks of each policy, and we have four possibilities: masking first, unmasking first, alternating (MUMU…), alternating (UMUM…). The total number of cases will be:

StrategyTotal cases
masking first57 000
unmasking first513 000
alternating (MU…)127 000
alternating (UM…)154 000

Of course, the growth rate will not remain constant. The longer we delay, the more people are immune. In the last week close to 2 million vaccine doses have been administered in the UK. That means that a 4-week delay means about 4 million extra people who are effectively immune. If we mask first, the higher growth rate will come later, thus the growth rate will be lower, and more of the cases will be mild.

The only thing I can suppose is that someone did an economic cost-benefit analysis, and decided that the value of increased economic activity was greater than the cost of lives lost and destroyed. Better to let the younger people — who have patiently waited their turn to be vaccinated — be infected, and obtain their immunity that way, than to incur the costs of another slight delay while waiting for them to have their shot at the vaccine.

The young were always at the lowest risk in this pandemic. They were asked to make a huge sacrifice to protect the elderly. Now that the older people have been protected, there is no willingness to sacrifice even another month to protect the lives and health of the young.

Update on Delta in Germany

The Robert Koch Institute produces estimates of variants of concern on Wednesdays. My projection from two weeks ago turns out to have been somewhat too optimistic. At that point I remarked that there seemed to be about 120 delta cases per day, and that that number hadn’t been increasing: The dominance of delta was coming from the reduction of other cases.

This no longer seems to be true. According to the latest RKI report, the past week has seen only a slight reduction in total cases, compared to two weeks ago, to about 604/day. And the proportion of delta continues to double weekly, so that we’re now at 59%, meaning almost 360 Delta cases/day. The number of Delta cases has thus tripled in two weeks, while the number of other cases has shrunk by a similar factor. The result is a current estimated R0 close to 1, but a very worrying prognosis. We can expect that in another two weeks, if nothing changes, we’ll have 90% Delta, around 1100 cases in total, and R0 around 1.6.

Of course, vaccination is already changing the situation. How much? By the same crude estimate I used last time — counting single vaccination as 50% immune, and looking back 3 weeks (to account for the 4 days back to the middle of the reporting period, 10 days from vaccination to immunity, and another 7 days average for infections to turn into cases), the above numbers apply to a 40% immune population. Based on vaccinations to date the population in 2 weeks will be 46% immune, reducing the R0 for Delta to around 1.5. In order to push it below 1.0 we would need to immunise 1/3 of the remaining population, so we need at least 64% fully immunised. At the current (slowed) rate of vaccination, if it doesn’t decelerate further, that will take until around the middle of September, by which point we’ll be back up around 10,000 cases/day.

Delta may not mean change

Germany is in a confusing place with its pandemic developments. Covid cases have been falling as rapidly here as they have been rising in the UK: More than 50% reduction in the past week, dropping the new cases to 6.6 per 100,000 averaged over the week, under 1000 cases per day for the first time since the middle of last summer. At the same time, the Delta variant is rapidly taking over. Last week the Robert Koch Institute reported 8%, this week it’s 15%. Virologist Christian Drosten, speaking on the NDW Coronavirus podcast this week (before the new Delta numbers were available) spoke of the 80% level in England that, he said, marked the watershed between falling and rising case numbers.

I think this is the wrong back-of-the-envelope calculation, because it depends on the overall expansion rate of the virus, and the difference between Delta and Alpha, which is likely particularly large in the UK because of the large number of people who have received just one AstraZeneca dose, which seems to be particularly ineffective against Delta. There’s another simple calculation that we can do specifically for the German situation: In the past week there have been about 810 cases per day, of which 15.1% Delta, so, about 122 Delta cases per day. The previous week there were about 1557 cases per day, of which 7.9% Delta, so also about 123 Delta cases. That suggests that under current conditions (including weather, population immunity, and social distancing) Delta is not expanding. This may mean that current conditions are adequate to keep Delta in check, while Alpha and other variants are falling by more than 50% per week.

This suggests a very optimistic picture: that total case numbers will continue to fall. Within a few weeks Delta will be completely dominant, but the number of cases may not be much more than around 100 per day. And that ignores the increasing immunity: The infections reported this week occurred in the previous week, and the immunity is based on the vaccinations two weeks before that. With about 1% of the population being vaccinated every day, we should have — relative to the approximately 70% non-immune population* 20 days ago — already have about 15% reduced transmission by the first week in July. And at current vaccination rates we can expect, by the end of July that will be 30% reduced, providing some headroom for further relaxation of restrictions without an explosion of Delta cases.

That does raise the question, though, of why the general Covid transmission rate in Germany seems to be lower than in the UK. I don’t see any obvious difference in the level of social-distancing restrictions. Is it just the difference between single-dose AZ versus Biontech? If so, we should see a rapid turnaround in the UK soon.

* I’m very roughly counting each dose as 50% immunity.