Japan’s medical surveillance system: Something to learn from in fighting a contagion

IN its March 29 issue, featured a highly informative article by Matt Aizawa in which he discussed the difference between Japan and the United States in their response to the coronavirus pandemic.

He suggests that the difference could explain why the coronavirus disease 2019 (Covid-19) spread at sharply different speeds in the two countries.

Japan employs meticulous medical detective work and probably better surveillance system.

On March 6, Aizawa said, the US and Japan had about the same number of Covid-19 cases — 311 and 348, respectively.

Ten days later, cases rose to 4,509 in the US, while Japan reported only 809. Five days later, the number of cases in the US spiked to 23,661 versus Japan’s 996. What is going on?

There has been much speculation about cultural differences. One is a handshaking, hugging society, while the other simply bows.

There is even speculation that Japan misreported the numbers to save the Olympic Games in Tokyo. Now that the games have been postponed, the governor of Tokyo, Yuriko Koike, has become openly alarmist.

Epidemiologists are still wondering what crucial steps Japan took or didn’t take.

The answer may be the nationwide network of medical detectives at the National Institute of Infectious Diseases (NIID) in Japan. Their daily briefing papers reveal a lot about infectious disease surveillance in Japan.

Japanese doctors are legally required to report all cases of infectious diseases to NIID, which immediately establishes a case number and sets up a surveillance team of medical detectives to track all those who had close encounters with the patient.

When a man in his 30s living in Kanagawa was diagnosed as a coronavirus carrier on January 16, the medical detectives identified, isolated and used the standard polymerase chain reaction (PCR) test on 38 people.

To date, the NIID has focused PCR testing on such pinpoint targets instead of performing mass testing as done elsewhere. South Korea had to resort to mass testing because on day two of its first diagnosis, there was credible evidence of 5,000 close encounters in a church.

In the NIID cases, 1,387 individuals proved positive, among whom 148 individuals were asymptomatic; 1,212 were hospitalized, of whom 56 required ventilators; and 331 have been discharged from hospitals.

Every one of these cases is closely monitored by NIID and the data are available online. Many of these cases have identified transmission points. The medical detectives know where and how the people got the virus. The transmission point, whether a theater or a gym, is shut down and sterilized.

A troubling trend emerged this past week. The medical detectives were finding cases that couldn’t be traced to a transmission point. What epidemiologists call “community spread” has begun. This is happening in New York City, where only 3 percent can be traced.

The earlier community spread in Hokkaido appears to be settling. But untraceable cases are emerging in Tokyo and Osaka. This is why Governor Koike issued a stay-home warning last week. The postponement of the Olympic Games was likely coincidental.

Pinpoint testing will continue. But if cases of community spread increase, Japan will have to engage in mass testing, as well.

So, what did Japan do that distinguishes its case numbers from the US? Probably better surveillance, meticulous medical detective work. You can see it daily at the Ministry of Health, Labor and Welfare’s homepage.

In the fight against Covid-19, it clearly matters plenty what strategy or plan of action a national government adopts in carrying on the struggle. The United Kingdom and India are harvesting the cost of tarrying before finally ordering their own lockdowns of key cities in their territory.

It helps even more if a country or a government has a system that has long been in place ready to work

The sad and deadly development in various Western countries is not accidental.