This coronavirus is catastrophically contagious. Now Japan is beginning to learn that – only because its initial strategy of tracing worked so well, until it did not.
So what is tracing? Remember Dr. Anthony Fauci’s words: “You’ve got to test, trace and isolate.”
Once a patient is identified, public health workers must trace his path for the previous two weeks to identify all those with whom he may have had close encounters.
Workplace, restaurants, taxis, home must be scrutinized for possible source of infection and for others similarly infected. When Japan’s case #1 was discovered on January 16, case workers identified and tested 38 other individuals.
For every new case found in January and February, about ten close encounter cases were traced and tested. New cases were usually fewer than a dozen a day and traceable to known cases.
This strategy of tracing and testing began to leak in March, as had been expected by some of the infectious disease caseworkers.
First, cases that could not be traced to known clusters began to outnumber those that could be traced. Community spread had begun. Some prefecture-level governments took a page from South Korea and began drive-thru Covid-19 testing.
After much cajoling, Prime Minister Shinzo Abe finally declared a state of emergency on April 7 and a partial shutdown was ordered in Tokyo, Osaka and other cities. There were 3,906 known cases in Japan on that date, after a total of 55,311 tests.
Under pressure from abroad Abe pressed for more testing, but the healthcare bureaucracy, dominated by medical professionals, was more worried about the perils of loading hospital beds with non-urgent cases.
This leads to the second issue: Japan underestimated how contagious this virus can be and did not prepare quarantine facilities or transport for moderate cases. Asymptomatic carriers are known to be infectious.
Some prefectures are now taking a page from Taiwan and booking entire hotels for isolating moderate and asymptomatic cases. Honda Motors has made special compartmentalized vehicles for transporting them.
Previously, they were told to go home via public transport and then isolate themselves, the latter despite numerous cautions from China about family contamination.
Even health care professionals underestimated the contagiousness of the virus. Supposedly safe wings of hospitals are reporting cases spreading from the cordoned-off Covid-19 wings.
Taiwan got it right
Taiwan fully understood the danger of underestimating the contagiousness of this virus. A March 18 news photo shows a team of Taiwan’s paramedics in full hazmat gear screening Taiwanese stranded in Wuhan before permitting them to board a plane for Taiwan.
By comparison, two less well garbed Ministry of Health workers who boarded the virus-infected Diamond Princess cruise ship in Yokohama contacted Covid-19.
It should be noted that the vice president of Taiwan is a professional epidemiologist who led the response team during the 2003 SARS outbreak.
Covid-19 cases in Taiwan increased from 100 on Mar 18 to 420 on Apr 20, according to Johns Hopkins. That is compound daily growth rate of 4.4%.
During the same 33 days, Japan’s increased from 868 to 10,797 cases, a 7.9% compounded daily growth rate based on a total of 112,816 tests.
Singapore’s cases increased from 266 to 6,588, which is 10.2% compounded daily growth, suggesting that warm weather may not slow down this virus.
Cases in the US increased from 8,343 to 758,720 – 14.7% compounded daily growth, one of the highest rates among peers.
The state of Massachusetts became the first state to recruit Covid-19 tracers this month, something that Asian countries have been doing since before epidemic became pandemic.
South Korea’s cases exploded early on, but the country now reports new cases in only single digits per day. The country is in its own major league.
Prime Minister Abe has been vocal in pressing for broader testing beyond people who have had close encounter with known cases. He has pledged capacity for 20,000 specimens a day, or four times the recent run rate of 5,000.
Niigata and Nagoya prefectures already have started drive-thru testing and Tottori plans to begin this month. More prefectures are booking entire hotels for isolating non-critical cases away from homes and families.
Finally switching to the full three-pronged strategy of test, trace and isolate, Japan may sufficiently broaden the testing and strengthen the isolating. Under the partial shutdown, we may see results over the next two to three weeks.
Source: Ministry of Health, Labor & Welfare, April 19
As of April 19 or 94 days since the first case was reported in Japan, the number of cases has exceeded 10,000.
Log chart remains within the estimated band width (orange parallel lines).
Number of new cases per day could still spike. Recent fatality rate is 1.55%
Prime Minister Abe pledges Covid-19 testing to increase to 20,000 per day versus recent 5,000 per day.