Author’s note: This is a copy of the white paper of the Working Group, a group of four pseudonymous professionals in Tokyo. I, Patrick McKenzie, was the primary author. It was distributed quietly during the week of March 25th, 2020. I have written an essay describing how this document came to be and demonstrating its provenance.

The covid-19 situation evolves very quickly. The white paper is presented unedited, as a historical document.

You can rely on this URL not changing if you need to cite this white paper specifically; the Working Group does not directly control any other copy on the Internet.


Japan will face rapid acceleration of covid-19 in April, leading to a public health crisis

The governmental and media consensus is that Japan is weathering covid-19 well. This consensus is wrong. Japan’s true count of covid-19 cases is understated. It may be understated by a factor of 5X or more. Japan is likely seeing transmission rates similar to that experienced in peer nations, not the rates implied by the published infection counts. The cluster containment strategy has already failed. Japan is not presently materially intervening at a social level. Accordingly, Japan will face a national-scale public health crisis within a month, absent immediate and aggressive policy interventions.

Update as of the afternoon of March 26th: The government’s panel of experts has said that infections are highly likely to be “rampant.” We concur with that assessment. We are presently unaware of published official projections consistent with the projections discussed in this white paper, with the exception of the one from Osaka, discussed below.

The consensus

As of March 24th at 3 PM JST, Japan has reported 1,135 cases (excluding those aboard the Diamond Princess, charter flights, and officers attending to them), of which 859 are active, 54 are critical, and 41 have resulted in the death of the patient.

The government has messaged a wait-and-see attitude (検討する) with respect to proactive containment measures outside of diagnosed clusters. There do not exist official reports of material community spread outside of surveilled clusters.

The current figure is likely a massive undercount. If it is an undercount, it is highly unlikely that Japan’s official position that it is correctly identifying most clusters quickly and preventing spread from them is accurate. As Japan’s strategy is built around aggressive treatment and containment of clusters, breakout from clusters is an emergency. It threatens rapid uncontrolled increase in infections, which will cause a breakdown in care (which Japan refers to as an “overshoot”) when the hospital system is overwhelmed, leading to a sharp increase in deaths.

We have statistical evidence suggesting that containment failure and community spread has already happened.

Reasons to doubt the consensus

Japan is undercounting asymptomatic individuals, who can spread the virus.

Japan has had a public policy of refusing to test asymptomatic individuals except for those having a deep degree of direct contact with an infected individual (濃厚接触者), and initially only tested individuals with contact if they also had a fever or difficulty breathing. (「濃厚接触者」については、発熱や呼吸器症状が現れた場合、検査対象者として扱う)

Accordingly, we should expect this testing policy to underdetect asymptomatic infections, and indeed we have evidence suggestive of this.

The Ministry of Health, Labor, and Welfare has released national statistics for patients who were diagnosed with covid-19 as a result of a PCR test on 3/10, 3/11, 3/12, 3/13, 3/14, and 3/23. These statistics include breakdowns by whether a patient was symptomatic when diagnosed or asymptomatic. Asymptomatic patients are consistently roughly 10% of all diagnoses (ranging from a low of 10.24% to a high of 11.29%). This is far less than we should expect for covid-19.

Japan’s experience on the Diamond Princess is instructive of what we should see if everyone in a population were extensively tested. All passengers were tested, repeatedly, before being allowed to disembark. The National Institute of Infectious Diseases reports that 48% of infected patients were asymptomatic at the time of sample collection.

If the true rate of asymptomatic infection is higher than the observed rate of asymptomatic infection, and we make the generous assumption that 100% of symptomatic patients are successfully identified, then there must be a large population of asymptomatic infectious carriers who are not counted in official statistics. They are not subject, unless they are in direct contact with an infected individual, to any restrictions, monitoring, contact tracing, or medical care. They do not consider themselves ill. They do not know they are capable of spreading the disease to others.

To estimate how many asymptomatic infections are being missed, we divide the number of cases of diagnosed symptomatic infections by the estimate of the true rate of symptomatic infections (which is lower than the observed rate). This gives us an estimate for the true number of infections. The difference between this estimate and the current official count are estimated asymptomatic infections which have not been diagnosed.

E.g. Using the March 22nd Ministry of Health, Labor, and Welfare data:

907 / (1 - 0.48) =\~ 1,750 true infections

This is approximately 70% higher than the number of detected infections on March 22nd.

This also magnifies the impact of any underdetection or misclassification of symptomatic infections. For every symptomatic infection missed by the current regime, we are also likely missing an asymptomatic infection.

Iceland’s chief epidemiologist, who has testing capacity to cover almost the entire population of Iceland, reports that 50% of their infections are asymptomatic. If this ratio held in Japan, it would suggest Japan has \~80% more infections than are publicly reported.

A pre-print from the Journal of Infectious Diseases, by a Japan-based team, uses Japanese citizens’ experience to calculate the asymptomatic rate. Japan evacuated citizens from Wuhan and exhaustively tested them on returning to the country, catching more asymptomatic infections than the testing strategy Japan generally employs. The researchers arrive at an asymptomatic ratio of 30.8%. This suggests that Japan has \~30% more domestic cases than are currently reported, again assuming perfect identification of all symptomatic cases.

A pre-print from Eurosurveillance estimates the true asymptomatic rate on the Diamond Princess at 17.9%, using more sophisticated modeling than the calculation we performed above. This again implies that Japan is undercounting cases, though not as dramatically as either of the above estimates would suggest.

Japan’s reported deaths are likely caused by a larger infection count than it is reporting.

A pre-print from the Center for Mathematical Modeling of Infections diseases, Using a delay-adjusted case fatality ratio to estimate under-reporting, attempts to calculate the true number of cases by reasoning from predicted case fatality ratios (CFRs). Each death observed in a country at a particular date corresponds to, probabilistically, approximately 1 / CFR infections occurring over an interval of several days prior to the observed date of death.

This research estimates Japan’s detection rate to be between 15% and 35%. Accordingly, Japan is undercounting cases by a factor of approximately 3X to 6X.

Countries that test people who have been in Japan find more infections than Japan does.

Singapore has traced four coronavirus cases to individuals who had just been in Japan.

To be conservative we’ll assume three of these infections, not four, are Japan-related, as we have no knowledge of travel of the Japanese Singaporean resident. Due to the usual course of the disease, Singaporean health authorities concluded it is likely that these individuals contracted it while they were in Japan.

Singapore’s sole airport keeps statistics of inbound passengers by country. The average passengers per month over February and March in 2018 and 2019 (most recent data available) was 128,000. Over a roughly 2 week period, we would expect approximately 64,000 passengers to fly from Japan to Singapore. 3 infections in that population is a rate of approximately 47 basis points, which is 5X the 9 basis points rate of infection in Japan. If one believes the government, the rate with surveilled clusters backed out be a tiny fraction of 9 basis points.

This implies either that tourists are exceptionally unlucky at stumbling into exactly the wrong music shows or medical facilities or, in the alternative, that there is unsurveilled community transmission bringing Japan’s true case count to many, many times the admitted count.

Why does Singapore’s airport detect more infections in people who have been in Japan than Japan detects in people who have been in Japan? It is likely because Singapore’s airport tests aggressively and Japanese medical offices do not.

If we believe it is credible that tourists passing through Japan encounter clusters at the same rate as people who stay in Japan, which is unlikely, this implies the official count is understated by 5X. If tourists are only getting affected by community transmission, this implies the official count is understated by 25X or more.

Where are the missing asymptomatic cases?

Japan’s official position, as stated at the March 19th Panel of Experts on NHK (「感染拡大地域では自粛検討を」専門家会議が提言) as well as elsewhere, is that Japan is focusing on a cluster-based containment strategy.

Japan’s testing capacity is underused, as a matter of policy. Local health offices control access to testing. The Japanese Medical Association has alleged, as reported by NHK, that doctors were denied permission to test more than 290 patients where the doctors felt the tests were medically necessary. Testing capacity (where it is used) is allocated to symptomatic individuals (preferentially to those with contact with diagnosed individuals or travel histories to epidemic-afflicted regions) and people with high degrees of contact with diagnosed individuals.

The inference is thus that missing asymptomatic cases are outside of identified clusters, in the general population, potentially causing community transmission.

The above statistics are strong circumstantial evidence of a very material number of non-clustered cases, which risk community transmission. We have direct evidence of community transmission as well: local Japanese governments are beginning to report it.

Japan’s containment strategy is failing

Japan official sources at the prefectural level are beginning to acknowledge that containment efforts locally are failing.

For example, Osaka Prefecture and Hyogo Prefecture are currently epicenters of the outbreak in Japan. In a document which Gov. Yoshimura showed on TV on March 21st and is dated as having been prepared on March 16th, experts acknowledged that cluster containment was failing, as evidenced by new infections without a detected link to an existing cluster (community transmission). Quote: “It is believed that infections without surveilled chain to a cluster continue to increase and that therefore a rapid increase in infections has already begun.” (見えないクラスター連鎖が増加しつつあり、感染の急激な増加がすでに始まっていると考えられる。)

Aichi Prefecture (Nagoya) has reported and unreported shortages of hospital beds suitable for high-grade infectious disease treatment (like covid-19) and generally. Asahi Shinbun reported on March 11th that over half of their capacity (161 beds) was already used. It was not generally reported at that time that they had begun triage. According to the prefecture on the 22nd, there are currently 103 hospitalized patients. 27 of them have not been tied to either of the prefecture’s known clusters. Nagoya is likely in a state of uncontrolled outbreak and medical care will likely suffer there, within days.

As of March 19th, the government’s declared containment strategy remained rapid cluster identification, surging medical attention on diagnosed patients, and asking for voluntary changes in behavior from the populace.

The cluster containment strategy has failed. Medical care in epicenters will be modified to adjust to a worsening reality, within days. The voluntary behavioral changes have been modest. They have been insufficient to maintain viability of the first two prongs of the strategy. We should not expect this level of behavioral change to prevent the situation from worsening.

Travel within Japan is routine, central to commerce and leisure, and almost entirely unimpeded. In normal times, there are 500,000 passengers on the Tokkaido Shinkansen between Tokyo and Osaka per day. In February, usage of it was down by only 8%, per the Nikkei Shinbun. An outbreak in Osaka, Nagoya, Tokyo, or similar major metropolitan areas is extremely likely to metastasize throughout Japan absent aggressive restrictions on movement, especially public transportation. This outbreak and subsequent spread has almost certainly already happened.

Japan is not materially preparing at a societal level

It has been widely reported domestically and internationally that the Japanese populace is extremely cooperative, hygiene-focused, and has a culture of donning masks to prevent infecting others and/or as a precaution against seasonal hay fever. This is not a strategy. We are already observing breakout infections. We should assume, until we see persuasive evidence otherwise, that infection spread in Japan resembles that of peer nations taking minimal precautions. This requires us to believe the evidence of our eyes and our instruments, not the evidence of our hopes.

The concrete action taken by Japan was suspending substantially all schooling nationwide on February 27th, two weeks before the spring holiday. Japan has discouraged large events, such as the live music event which generated Osaka’s first surveilled cluster. Aside from these measures, and individual citizens and organizations adopting very modest levels of caution, it is business as usual.

By casual observation, mask wearing in central Tokyo is below 30%, including in well-attended outdoor events such as hanami (cherry blossom watching) parties. Reporters have not observed social distancing or universal mask use at press conferences about the epidemic.

The government has recently released guidance that recommends masks most strongly in environments which are enclosed, with high density of people, with conversations or vocalization. This recommendation has not succeeded in closing bars or restaurants, and appears to carve out mass transit and hanami, which are economically and socially significant. It is uncertain the degree to which this carveout is warranted by medical science.

Japan will face a national health crisis within a month

Osaka forecasts a likelihood of 3,374 infections (including 227 severe cases) before April 3rd, compounding a rate of more than 6X per week. (This estimate was included in the document shared by the governor.) New York, with aggressive measures to slow the spread of disease, shows compounding of only approximately 2X per week.

If government infection counts were accurate, but containment has failed, and we use optimistic doubling rates observed in peer nations taking aggressive measures, we would expect to see on the order of 3,000 cases, including more than 200 severe cases, in each of Nagoya, Osaka, Tokyo by the end of April.

If we do not use peer nations’ experience for doubling rates, and instead rely upon the estimates of the cluster identification working group who prepared the report for Osaka, and we do not implement aggressive measures to slow the spread of disease, we could see more than ten times to one hundred times that number.

These scenarios both will likely lead to a breakdown in provision of care, which Japan refers to as an “overshoot.” The experience of peer nations suggests that that would lead to patients dying in the wake of care being impeded, at a sharply increased rate, and in patients of other conditions dying as other forms of medical care are also impeded.

Tokyo on March 23rd announced that it had 118 beds appropriate to safely treat high-level infectious disease patients, with plans of adding 700 beds for severely affected patients and 3,300 for those with moderate symptoms.

Additionally, the bottleneck is likely not beds but rather skilled medical personnel; Japan faces an ongoing shortage of them at the best of times. Japan is likely unable to surge them from unaffected regions to epicenters. Many medical personnel already live in epicenters. Those that don’t will be equally needed to treat the likely coming uncontrolled outbreaks at home.

The above scenarios apply estimates of growth rates to currently reported numbers of infections. The currently reported numbers are very likely not accurate. They are, as described above, a gross undercount. Reality is very likely worse than current guidance from official sources, and therefore the April we encounter will be worse than observers who rely on those numbers suppose.

We project a true count of over 500,000 infections, including more than 5,000 severe cases, and a breakdown in provision of care (“overshoot”) in Nagoya, Osaka, and Tokyo, before the end of April. There will almost certainly be other breakdowns nationally. April is extremely unlikely to be the worst month. Accordingly, by the end of April, we will have an undeniable national public health emergency.

Japan must act now

As of March 19th, the government’s declared policy was that it would wait-and-see about infection spread and consider asking the public to engage in voluntary (自粛) social distancing in regions with outbreaks. Jake Adelstein reported “However, a Japanese official who gave an off-the-record briefing to Asia Times suggested that a “don’t ask, don’t tell” strategy, based on minimal testing and buttressed by information massage, has been quietly emplaced.”

Governor Koike of Tokyo floated a trial balloon on March 23rd contemplating the possible lockdown of Tokyo if there were an outbreak in Tokyo, while emphasizing that a lockdown should be avoided at all costs. Governor Koike announced, on March 25th, a voluntary stay-at-home order for Tokyo starting on March 28th.

Many cities in peer nations have experienced what we will soon experience. We do not believe they would advise us to delay our response.

As a nation, we believe we are in a peaceful spring.

We are not.

We will, within the month of April, confront a crisis worse than any since the war. We must take immediate, concerted, aggressive policy steps in light of this reality.