Covid-19 in Japan: Numbers vs. Testing

Every day Tokyoites are anxiously waiting for the latest daily count of new confirmed Covid cases: Is it less than 200 or more than 200? It was a big thing when it first exceeded 100. On April 11, it barely missed the next big number with 197 cases. But what does it really mean?

“Cases of Covid-19 confirmed with PCR tests” depends as much on the number of tests conducted as the actual number of people newly infected. Anyone not tested is by definition not included in the count. Until now, anyone testing positive has been sent to a hospital, which supposedly is legally required (only recently have light cases been moved out to specially rented hotel rooms). Therefore hospitals have been reserving tests to people with the most severe symptoms or with pre-existing conditions so that the most deserving patients will occupy the limited hospital beds they can take up.

It may seem counter-intuitive, but the primary purpose of testing has not been to track the growth of infections but to allocate hospital beds. The number does not reflect reality as it is artificially throttled. As long as this policy continues, new confirmed cases will basically only be allowed to grow at a rate at which hospital beds are found for them, which is becoming increasingly difficult, as more and more hospitals are turning away new patients to avoid healthcare associated infections (HAI). There have been a number of cases of infection hotspots in hospitals.

An article in the The Atlantic discusses positivity, the rate of confirmed infections found as a share of tests conducted in different states and countries (please don’t confuse this with prevalence, the rate of infected people as a percentage of the population).

Basically, the higher the percentage of tests that come out positive, the more likely a country or region is to be undercounting infections, for example because of limited lab capacities or limited access to hospitals that can do testing:

“[W]hile the U.S. has a 20 percent positivity rate, South Korea’s is only about 2 percent—a full order of magnitude smaller.

South Korea is not alone in bringing its positivity rate down: America’s figure dwarfs that of almost every other developed country. Canada, Germany and Denmark have positivity rates from 6 to 8 percent. Australia and New Zealand have 2 percent positivity rates. Even Italy—which faced one of the world’s most ravaging outbreaks—has a 15 percent rate. It has found nearly 160,000 cases and conducted more than a million tests. Virtually the only wealthy country with a larger positivity rate than the U.S. is the United Kingdom, where more than 30 percent of people tested for the virus have been positive.

Comparing American states to regions in other countries results in the same general pattern. In Lombardy, the hardest hit part of Italy, the positive rate today stands at about 28 percent. That’s comparable to the rate in Connecticut. But New York, so far the hardest hit state in the U.S., has an even higher rate of 41 percent. And in New Jersey, an astounding one in two people tested for the virus are found to have it.”

(The Atlantic, 2020-04-16)

So what this tells us is that a high positive rate in the tests conducted indicates a higher rate of uncounted cases that the system can’t keep up with.

What does that mean about the potential undercounting of explosive infection growth in Japan and specifically in Tokyo? According to statistics published by the Tokyo Metropolitan government on its website, by yesterday (April 16) Tokyo had 2,595 confirmed Covid-19 cases out of 7,244 cases tested. That’s a positivity of 36%, higher than the positivity for the UK (30%), Lombardy and Connecticut (28%), the US overall (20%), Italy (15%) and Canada, Germany or Denmark (6-8%). Only New York and New Jersey are worse.

Recently, Germany has been running 350,000 tests per week and is capable of running up to 500,000 tests per week. Tests are analyzed 7 days a week, 24 hours a day using shift work in the labs. Japan, with a population 52% larger, has averaged 22,000 tested individuals per week over the past two weeks (Apr 2-15).

Don’t take any comfort from numbers staying flat or growing moderately unless testing is also expanded exponentially to keep up with and exceed the growth rate of virus cases. Without greatly expanded testing, we’re like a pilot flying blind in a cloud without radar. Beware of the mountains ahead.

See also:

Covid-19 in Japan: Where are the experts?

America has Dr. Anthony Fauci and Dr. Deborah Birx, who provide scientific information at White House press conferences.

Germany has Prof. Dr. Lothar Wieler of the Robert Koch Institute, who speaks at biweekly press briefings. Dr Christian Drosten, chief virologist at the Charité hospital in Berlin, has provided frequent commentary to the public.

Where are these experts in Japan? The briefings I have watched in Japan primarily involved Prime Minister Abe Shinzo and Governer of Tokyo Koike Yuriko.

Yes, individuals scientists have been interviewed by the “wide shows” entertainment programs, but why are they not given a prominent official role in shaping public responses to the epidemic? Yes, the declaration of emergency is supposed to be based on the discussions of a circle of experts, but we don’t directly hear from them. It’s only the government who consults with them.

The impression this creates is that the decisions being made are ultimately driven by political and economic considerations, which take priority over any medical interpretation of the situation.

As Son Masayoshi of Softbank pointed out in a recent tweet, it is strange that in Japan Covid-19 policy is spearheaded by the Minister of Economic Revitalization instead of a health expert such as Dr. Fauci in the US. That tells you all you need to know about the priorities of the Abe government.

Covid-19: Fleeing to the countryside

Following the “not a lockdown” in Tokyo and 6 other prefectures, the summer resort town of Karuizawa has reportedly experienced an influx of cars with Tokyo license plates as Tokyo residents with second homes (bessō) in the area are flocking to the town in Nagano that is not yet subject to the restrictions.

I would expect a similar pattern to unfold in resort areas around Yamanakako and Izu (in Yamanashi and Shizuoka, also not among the 7 prefectures).

Not only does this exodus from the city risk the spread of infections to prefectures that currently still have a lower incidence of Covid-19, it could also have infected bessō owners take up rural hospital beds then no longer available for the local population after they also get infected.

Other countries have clear policies that discourage people from dashing to second homes, which earned Prince Charles some criticism for self-quarantining in Scotland and cost Scotland’s chief medical officer her job. Don’t get me wrong, I understand why they’re doing it, but it’s selfish and against the spirit of sheltering in place. Why should others stay put in their tiny Tokyo apartments when some can drive across the country?

While it can be said that refugees from the city will spread the load on the health care system between urban and rural hospitals, that is something the national government should be thinking about, not something only those rich enough to own two or more homes to take advantage of.

Covid-19: Japan to declare state of emergency

Quoting a government official, the local media (both English and Japanese-language) are predicting the government wil declare a state of emergency from as early as Tue, April 7 in big cities such as Tokyo and Osaka, to initially last until May 6 (Golden Week).

“The move would give governors in hard-hit regions legal authority to ask people to stay home and businesses to close, but not to impose the kind of lockdowns seen in other countries. In most cases, there are no penalties for ignoring requests, although public compliance would likely increase with an emergency declaration.” (Japan Times)

The number of confirmed infections with the SARS-CoV-2 virus have doubled in a week or less in Tokyo, Osaka, Kanagawa, Saitama and Chiba.

Here are the numbers on April 1 and April 6 and the corresponding doubling time in days:

  • Tokyo: 527 => 1033 (5.1d)
  • Kanagawa: 120 => 265 (4.4d)
  • Saitama: 98 => 185 (5.5d)
  • Chiba: 164 => 260 (7.5d)
  • Osaka: 245 => 408 (6.8d)
  • Hyogo: 147 => 203 (10.7d)
  • Aichi: 176 => 228 (13.4d)
  • Hokkaido: 177 => 194 (38d)

The growth rate in Tokyo and its neighbour prefectures Kanagawa and Saitama is similar now to growth in the US over the past couple of days (12-14% daily increase of total confirmed cases). The US expects daily deaths to peak at a rate of about double the current date rate in about 10 days if everybody follows social distancing rules.

Italy experienced similar growth levels around March 17, i.e. 20 days ago after it had been in shutdown for the first week. Over the next two weeks of total shutdown, Italy’s growth rate gradually dropped from 12-14% to 4% where it’s been stable for about a week now. It was only this weekend that the number of ICU beds in use slightly dropped, the first time since the beginning of the crisis in Italy.

I can see how the government would want to avoid hurting the economy in prefectures whose official case numbers are still low and therefore restricts the shutdown to only the worst-hit urban centers, but with no closed political borders it remains to be seen how effective a partial shutdown will be. Rural Japan has a much bigger elderly population than the cities. Will families in cities refrain from visiting their rural relatives? And will the population in the rest of Japan understand the severity of the situation when their prefecture is excluded from the shutdown?

Stories I have heard from friends of friends make me wonder.

One is invited to a wedding and the couple isn’t sure whether to go ahead, as there would be a huge cancellation fee to the hotel they booked. If the the government took action, this would no longer be a question.

Another was sick with a fever and breathing problems (i.e. symptoms matching Covid-19), yet the employer insisted he still come to work. I think that’s insane and outrageous.

A Japanese acquaintance I recently happened to meet still wanted to shake my hand when he saw me.

People who have been quarantined in Europe and North America have changed their thinking. In Japan this change of attitude was delayed by attempts to keep the Tokyo 2020 on course and now it will take time to turn the ship around.

See:

Covid-19 mortality in Germany

There have been many comments on the relatively low mortality in Germany relative to the number of confirmed cases. The median age of infected persons in Germany is 47 compared to 64 years in Italy. Many Germans were infected while skiing in Austria or northern Italy (the same is true for Norway and Iceland, which also imported the problem this way) and these younger, healthier patients have a lower risk of severe outcomes.

Germany has relied heavily on PCR testing from an early stage. Because of this the total number of confirmed cases includes many light cases that might otherwise have remained undetected. Last week about 350,000 PCR tests were performed in Germany, an average of 50,000 a day. This compares to 28,000 people in total who have been tested in Japan so far. Japan’s population is about 50% larger than Germany’s.

By tracing these mostly mild cases with large scale PCR testing, the authorities have prevented the spread to other more at risk groups of the population.

The youngest person in Germany to die from Covid-19 so far was 28 years old and had a pre-existing condition.

There is a distinct gender bias in fatality. 84% of the 31 persons under 60 to die were male (26m, 5f). 73% of the 44 persons between 60-69 were male (32m, 12f). In the 70-79 bracket, 78% of the 130 who died were male (102m, 28f). For 80-89, the largest age group with 305 deaths, the ratio is 61% male (185m, 120f) even though far fewer men reach this age than women. Even in the 90 and above bracket (71 deaths), male deaths still outnumber female deaths (38m, 33f).

On March 30, the number of new infections in Germany dropped close to the number of fresh recoveries (4,450 vs. 4,289), which recently increased. Combined with 104 deaths this meant that the number of active cases (total confirmed infections – deaths – recoveries) only climbed by 57 or 0.1%. This is the lowest rate of increase since the start of the epidemic, which if it continues gives reason to be hopeful.