Japan’s COVID-19 ‘excess mortality’ relatively low, but fails to show whole picture

11-Aug-2020 Intellasia | Mainichi | 6:02 AM Print This Post

“Excess mortality,” the number of deaths exceeding what would be seen in a regular year under normal circumstances, has been confirmed across the globe and is likely due to the spread of the new coronavirus. Interpreting excess mortality, which involves various factors, is no simple task, and the application of this concept has come under the spotlight to understand the actual scope of the coronavirus pandemic as it includes “hidden deaths” of COVID-19, where people have died of the infectious disease but were never diagnosed.

Excess mortality is a concept advocated by the World Health Organization and originally used to estimate the number of deaths in an influenza outbreak. Here is how it works: you first calculate the death toll with the hypothesis that there is no flu outbreak based on past statistics. You then compare the figure with the actual number of deaths to find out how many people died of the influenza.

A research team in Europe wrote in the British medical journal The Lancet in April that excess mortality could be the most objective and comparable method to evaluate the scope of a pandemic and draw lessons from it.

In Europe, where an explosive spread of the coronavirus has been observed, excess mortality was on a different level compared to what has been seen in Japan. According to EuroMOMO, a mortality database that releases the number of deaths in European countries, a total of at least 172,400 excess mortality cases was confirmed between the 10th and 22nd weeks of 2020, or between March and May. Those aged 65 and older made up 157,400 of those cases, highlighting the higher fatality risks faced especially by older citizens.

The excess mortality figure recently released by a research team in Japan’s Health, Labour and Welfare Ministry using the same calculation method as the one used in Europe, on the other hand, is harder to interpret. According to the health ministry team, excess mortality in five prefectures including Tokyo between the end of 2019 and April this year is estimated at up to 138. However, at least 400 people had died as of the end of April after being diagnosed with the new coronavirus.

Japan’s “138″ excess mortality figure cannot be evaluated as simply reflecting the effects of the coronavirus, as the overall death toll, regardless of their causes, is compared with the mortality figures counted in a regular year, and there is a possibility that traffic accident deaths had dropped due to people staying home to avoid infection, among other possibilities.

Koji Wada, a professor of public health at the International University of Health and Welfare, points out that excess mortality “shows up clearly when an explosive spread happens, as seen in European countries.” Compared to that, he continued, “Japan seems to have succeeded in containing the spread of the viral infection.” At the same time, Wada said, “excess mortality is an important index to monitor how infections are spreading, so we should continue checking it in preparation for a potential second wave of the outbreak.”



Category: Japan

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