The COVID-19 pandemic appears to have increased longevity in Japanese centenarians

Sir,

The coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 which started in Wuhan, China, at the end of 2019, has spread worldwide and was officially declared a pandemic by the World Health Organization on 11 March 2020 [1]. In Japan, despite the presence of many travellers from nearby China in January and February 2020, the spread of the virus was minimised, in contrast to Europe, during the first wave of COVID-19. Presumably, this was a result of the greeting etiquette of Japanese culture and the implementation of basic hygiene education, including use of face masks [2]. From 1 March to 31 December 2020, 3,290 people died from COVID-19 in Japan, but this figure amounted to −7,040 excess deaths. That is, during this period, there were 7,040 fewer deaths than would have occurred in a normal year. Such negative excess deaths were also observed in South Korea, Taiwan, Thailand and the Philippines, suggesting racial differences in susceptibility to COVID-19, above and beyond the public health countermeasures [3].

The Japanese Ministry of Health, Labor and Welfare annually publishes national data regarding centenarians on 15 September of each year. Figure 1 shows the annual changes in the number of Japanese centenarians from 2010 to 2020. The columns represent the number of centenarians (100 years old and over) on 15 September (Senior Citizen’s Day) of each year, while the dots represent the number of people who were, or would be, 100 years old by the end of the fiscal year (by 31 March of the following year). They were counted when alive on 1 September of the same year. It is notable that a sudden and considerable increase in the number of centenarians from 71,238 to 80,450 was unexpectedly observed during the COVID-19 pandemic in 2020. The expected number of 100-year-old centenarians increased from 37,005 in the fiscal year of 2019 to 41,802 in the following year. Compatible with the negative excess deaths mentioned above, the number of deaths from pneumonia was 64,965 in January through September 2020. This 2020 figure represented a decrease of 13,950 deaths from the same period in the previous year, 2019 (updated data) [4]. Similarly, the number of deaths from influenza was 941, which represented a decrease of 2,340 from the previous year. Such a decrease in deaths from infectious diseases appeared to occur in the oldest Japanese citizens, probably because of social distancing, resulting in this unexpected increase in the number of centenarians in 2020.

Figure 1.

Annual changes in the number of centenarians in Japan. Columns represent the number of centenarians (100 years old and over) on 15 September in each year, and dots represent the number of people who were or would be 100 years old by the end of the fiscal year (on 31 March). They were counted when alive on 1 September of the same year. A sudden and considerable increase in centenarians was unexpectedly observed during the COVID-19 pandemic in 2020.

Consequently, this sizeable increase in the number of Japanese centenarians suggests the importance of general precautions against viral infections, such as social distancing, in Japan’s oldest demographic. The support of immune potency would also be considered significant by exploring further the compromised immunity with ageing [5].

Declaration of Conflicts of Interest

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Declaration of Sources of Funding

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