Figure 1. Age-adjusted mortality rates (AMRs) over time and excess mortality in each month: all cancers.

(Left side) Observed age-adjusted mortality rates (AMRs) (per 100,000 population) are represented by a blue line with marks, the predicted trend by logistic regression analysis by a dashed line, and the 95% prediction intervals (PIs) by dotted lines. Markers are highlighted in yellow for years with figures exceeding 95% of the upper PI, and pink for years with figures exceeding 99% of the upper PI. The vertical line indicates the arrival of COVID-19 in Japan. There was a decreasing trend until 2020, but the decline stopped after 2021, with figures exceeding the 95% upper PI in 2021 and the 99% upper PI (the line was not shown) in 2022.

(Right side) The horizontal axis indicates each month during the pandemic in 2020, 2021, and 2022, while the vertical axis on the left side indicates the excess mortality (%), calculated as (observed AMR − predicted AMR in the corresponding month) / predicted AMR in the corresponding month*100. The predicted AMRs based on the 2010–2019 period preceding the COVID-19 pandemic were estimated by logistic regression analysis.

The ⁑ symbol signifies >99% upper PI, and † <95% lower PI. The vertical axis on the right side indicates the number of domestic vaccinations and deaths attributed to COVID-19.

Monthly excess mortalities exceeded the 99% upper PI for the first time in August 2021, coinciding with the peak of the first and second mass vaccinations, and once again exceeded the 99% upper PI for four months from May 2022, two months after the peak of the third mass vaccination.