Unmasking Twitter

On March 16 Twitter posted An Update on Our Continuity Strategy During COVID-19 that included this bit on how the company was changing its policies about content moderation:

Broadening our definition of harm to address content that goes directly against guidance from authoritative sources of global and local public health information. Rather than reports, we will enforce this in close coordination with trusted partners, including public health authorities and governments, and continue to use and consult with information from those sources when reviewing content.

So what is the latest guidance from authorities? The World Health Organization (WHO) helpfully has a tweet:

So does the CDC:

So does the U.S. Surgeon General:

What I thought was particularly noteworthy, though, was this tweet from the Surgeon General yesterday:

Everyone is taking their guidance from the WHO, and that’s a problem.

WHO and China

The Wall Street Journal, in an article in February, explored why the WHO seems to act with such deference to China.

When the World Health Organization declared a global public-health emergency at the end of last month, it praised China’s “extraordinary” efforts to combat the coronavirus epidemic and urged other countries not to restrict travel. “China is actually setting a new standard for outbreak response,” WHO Director-General Tedros Adhanom Ghebreyesus said. Many governments ignored the travel advice. Other public-health experts criticized his unqualified praise for China.

Among the complaints directed at Dr. Tedros: He was bending to Beijing by lauding a Chinese response that included quarantining 60 million people—which many health experts see as inconsistent with WHO guidelines—while calling on other countries not to cut off travel and trade with China…By praising China’s response effusively, the WHO is compromising its own epidemic response standards, eroding its global authority, and sending the wrong message to other countries that might face future epidemics, they say…

Dr. Mackenzie questioned why Chinese authorities appeared to delay reporting an increase in infections in the first half of January. Many health experts believe the outbreak spread more quickly early on because local authorities tried to cover it up, including by reprimanding a local doctor who sought to raise the alarm, and then were slow to announce it could pass person to person. “China is obviously an important player,” said Dr. Mackenzie. “So everything the WHO does has to keep that in mind. At the same time, you can be overly effusive.”

The entire article is well worth a read, but the takeaway is this: at every step of this outbreak the WHO has sought to praise and accommodate China, despite the fact that news about the initial outbreak was forcibly suppressed, the fact that China violated WHO guidelines with the severity of its quarantines (which to be clear, appear to have been effective), the fact that China hid the transmission rate amongst health care workers from the WHO until February 14 and waited weeks to even allow the WHO into the country, and only then on carefully scripted and chaperoned tours.

Those tours — which again, took weeks to negotiate, even as the coronavirus was spreading all over the globe — resulted in this report. It is, indeed, exceptionally effusive of the Chinese response, and contains no mention of China’s cover-up of human-to-human transmission in particular, which led to this tweet from the WHO:

This was particularly unfortunate given that Taiwan had told the WHO on December 31 that there was human-to-human transmission.

At the same time, much of the report is genuinely useful, particularly this warning to other countries:

COVID-19 is spreading with astonishing speed; COVID-19 outbreaks in any setting have very serious consequences; and there is now strong evidence that non-pharmaceutical interventions can reduce and even interrupt transmission. Concerningly, global and national preparedness planning is often ambivalent about such interventions. However, to reduce COVID-19 illness and death, near-term readiness planning must embrace the large-scale implementation of high-quality, non-pharmaceutical public health measures. These measures must fully incorporate immediate case detection and isolation, rigorous close contact tracing and monitoring/quarantine, and direct population/community engagement.

Had this been heeded by Western countries, all would be in far better shape than they are.

Asymptomatic Transmission

Even so, it might not have mattered, because of this paragraph:

Asymptomatic infection has been reported, but the majority of the relatively rare cases who are asymptomatic on the date of identification/report went on to develop disease. The proportion of truly asymptomatic infections is unclear but appears to be relatively rare and does not appear to be a major driver of transmission.

This is problematic in three ways:

  • First, it is at odds with evidence from the Diamond Princess (where every member of the population was tested), Iceland (where a statistically representative sample of the entire population has been tested), and South Korea (where testing was widely available even without symptoms); all show a high rate of asymptomatic infection.
  • Second, there are multiple | reports | from | China that asymptomatic carriers spread the virus.
  • Third, there is compelling statistical evidence that asymptomatic carriers drove the majority of the virus’s spread within China (and likely, by extenstion, around the world). This, notably, suggests that social distancing and travel bans are particularly effective.

It seems likely this paragraph about the lack of asymptomatic transmission was strongly argued for by China. Caixin reported at the beginning of March about China’s push in this area:

China’s decision to exclude individuals who carry the new coronavirus but show no symptoms from the country’s public tally of infections has drawn debate over whether this approach obscures the scope of the epidemic, with a document received by Caixin showing a significant proportion of one province’s cases show no symptoms. Since early February, the National Health Commission (NHC) has concluded that “asymptomatic infected individuals” can infect others and demanded local authorities to report those cases. However, the commission has also decided not to include these people in its statistics for “confirmed cases” or indeed to release data on asymptomatic cases.

In an interview with Nature last week, Wu Zunyou, China’s chief epidemiologist, defended the country’s treatment of asymptomatic data. He told the magazine that a positive nucleic acid test — a genetic sequencing test used to detect the coronavirus — does not necessarily indicate an infection because viral genetic material detected through throat or nasal swabs does not confirm the virus has entered cells and begun to multiply. This notion was also echoed by Chinese representatives at the WHO.

But this view has been challenged by both domestic and overseas experts, who said that a virus must have replicated to reach detectable levels.

I am no expert, but given that a virus cannot replicate on its own, but rather must leverage the body’s cells to churn out copies of itself, it seems rather self-evident that if it is detectable it has entered cells. And yet, Director General Tedros Adhanom Ghebreyesus argued — on Twitter! — that asymptomatic carriers were not a concern:

Again, an increasing amount of evidence is that this just isn’t true: asymptomatic carriers are a major problem.

Mask Efficacy

This is where masks come in. Much of the discussion of their efficacy has been focused on whether they keep you safe from the virus, and the evidence suggests that the answer is probably. SlateStarCodex has a comprehensive overview of the evidence here.

Everyone agrees, though, that those who are sick should wear masks; as the Taiwan CDC puts it, “Masks are mainly used for preventing the spread of disease and protecting people around you.” This, though, highlights the shortcomings of the “Don’t wear masks if you’re not sick” recommendations:

  • First, people are terrible in general at estimating if they are sick, particularly if their symptoms are mild.
  • Second, as Zeynep Tufekci argued in the New York Times, saying that only sick people should wear them stigmatizes the sick and makes them less likely to wear them.
  • Third, and most importantly, asymptomatic transmission means you don’t even know if you are sick in the first place.

This point was well-made by Sui Huang on Medium:

There is no scientific support for the statement that masks worn by non-professionals are “not effective”. In contrary, in view of the stated goal to “flatten the curve”, any additional, however partial reduction of transmission would be welcome — even that afforded by the simple surgical masks or home-made (DIY) masks (which would not exacerbate the supply problem). The latest biological findings on SARS-Cov-2 viral entry into human tissue and sneeze/cough-droplet ballistics suggest that the major transmission mechanism is not via the fine aerosols but large droplets, and thus, warrant the wearing of surgical masks by everyone.

This is where China’s push to exclude asymptomatic cases is so damaging: it excluded what may be the most important SARS-CoV-2 transmission vector, which resulted in the WHO not updating its guidelines, which may have resulted in far more people in the West getting sick than might have otherwise.

The good news is that the authorities appear to be listening: the Washington Post is reporting that the CDC is considering revisiting its guidelines, and suggesting that people use nonmedical masks or cloth coverings (because N95 masks and surgical masks should be reserved for healthcare workers); Austria already made masks compulsory, joining Slovakia, the Czech Republic, and Bosnia-Herzegovina (masks are, of course, widespread in most of Asia, although, contrary to popular belief, not compulsory by law, although often enforced by private businesses). Germany is considering the same.

To be very clear, N95 masks and even surgical masks, at least until they are widely available, should be saved for healthcare workers. That’s ok though: homemade masks work, and governments should be honest about that.

Twitter’s Theoretical Value

Twitter, in its guidelines, lists multiple examples of when it might enforce its new policy. The third one stood out:

Description of harmful treatments or protection measures which are known to be ineffective, do not apply to COVID-19, or are being shared out of context to mislead people, even if made in jest, such as “drinking bleach and ingesting colloidal silver will cure COVID-19.”

It sure seems like multiple health authorities — the experts Twitter is going to rely on — have told us that masks “are known to be ineffective”: is Twitter going to delete the many, many, many tweets — some of which informed this article — arguing the opposite?

The answer, obviously, is that Twitter won’t, because this is another example of where Twitter has been a welcome antidote to “experts”; what is striking, though, is how explicitly this shows that Twitter’s policy is a bad idea, not just because it allows countries like China to indirectly influence its editorial decisions, but also because it limits the search for truth.

You can think about the value of disagreeing with experts theoretically. Suppose that experts are correct 9 out of 10 times (and honestly, that’s probably low). However, if they are wrong, they have to pay out $100 (if they are right, they don’t get anything, because that is how the world works; the payout comes from being an expert in the first place). In this case, the expected cost of being an expert is:

9 x $0 + 1 x $100 = $100

-$100: yes, you may be right most of the time, but when you get it wrong, it is going to cost you.

Now, suppose experts have to put up with Twitter and having people question them. It’s a real pain in the rear end, what with all of the trolls and misinformation. To that end, let’s suppose every episode now costs the expert $5 because they have to argue with people who aren’t experts. This suggests the cost is:

10 x $5 + 1 x $100 = $150

The problem is that this overlooks the possiblity that the non-experts are sometimes right, or, perhaps more realistically, that they force the experts to re-visit their assumptions and predictions. Suppose that 10% of the time they are actually useful; now the expected cost is:

10 x $5 + 90%(1 x $100) = $140

Better than the worst case scenario, but not great.

That, though, isn’t quite right either, because it misses the fact that on a medium like Twitter, there are effectively infinite counter-arguments — indeed, that is why Twitter is so costly ($5) in the first place! The pay-off, though, is that the right argument is that much more likely to surface — let’s say 90% of the time. Now the expected cost is:

10 x $5 + 10%(1 x $100) = $60

That is a big improvement over the base case!

These numbers are, obviously, completely made up, but frankly, I think they are conservative. The cost of the coronavirus crisis in particular is so astronomical that basically any amount of investment to have avoided it or to ameliorate it is well worth it. Masks, hopefully, will be a good example: if Twitter is right, and the CDC is wrong, and economies are able to open sooner than they might have otherwise, that will be well worth all of the misinformation and terrible takes that Twitter produced in the meantime.

Internet Optimism

There is a further, even more optimistic, takeaway. In the analog world, politicians and experts needed the media to reach the general population; debates happened between experts, and the media reported their conclusions. Today, though, politicians and experts can go direct to people — note that I used nothing but tweets from experts above. That should be freeing for the media in particular, to not see Twitter as opposition, but rather as a source to challenge experts and authority figures, and make sure they are telling the truth and re-visiting their assumptions.

Indeed, while many on the right gripe that the media’s general opposition to Trump is driven by partisanship, I actually think it is a healthy approach to authority in general, particularly when that authority doesn’t need help going directly to people. Imagine if the media applied the same skepticism they give to Trump to the CDC or WHO, much less the Obama administration’s approach to the Great Financial Crisis or the Bush administration’s approach to Iraq (or, for that matter, Chinese data).

As I have argued from the beginning of this site, the Internet is an amoral force: it is up to us to decide if it is for good for bad. The best way forward is embracing Internet assumptions and using the overwhelming amount of information and free access to anyone to make things better, not try and build a moat around what experts say is right or wrong.

I wrote a follow-up to this article in this Daily Update.