疫学：COVID-19による死亡者数がブラジルの平均余命を短くしている

The total reported deaths caused by COVID-19 in Brazil reduced life expectancy at birth by 1.3 years in 2020 and by 1.8 years from January to April 2021, according to a paper published in Nature Medicine. In some states, life expectancy in the face of COVID-19 has been reduced to levels not seen in 20 years, with the greatest drop being 3.46 years in Amazonas state in 2020.

April 2021 was the deadliest month since the pandemic began in Brazil: nine capital cities reported more deaths than births. The consequences of that death toll can be measured by life expectancy at birth, which indicates the average number of years a newborn would be expected to live if born in a specific year, given the prevailing mortality rates in that year throughout life. As the risk of dying from COVID-19 is greater at older ages, the death toll can also be reflected by considering changes in life expectancy at age 65—the number of years a person would be expected to live if they continued to be subject to the underlying mortality rates for ages 65 and above of a specific year.

To quantify the consequences of COVID-19-related deaths on the population of Brazil, Marcia Castro and colleagues analyzed data on reported total deaths in 2020 and from January through April 2021 to measure the death toll across states. On the basis of the total number of deaths reported in Brazil in 2019 and 2020, the authors estimated a reduction of life expectancy at birth of 1.31 years, with a larger drop for males (1.57 years) than for females (0.95 years). The estimated decrease in life expectancy at age 65 was 0.94 years. In 2021, from 1 January to 25 April, the life expectancy at birth fell by 1.78 years, and life expectancy at 65 fell by 1.05 years. On average, the authors observed larger decreases in life expectancy at birth and at age 65 in the North region of Brazil, both in 2020 and 2021. This region has some of the worst indicators of income inequality, poverty, access to infrastructure and availability of physicians and hospital beds, and was less stringent in the implementation of control policies (compared to the Northeast region, for example).

The authors argue that without immediate changes to the pandemic response and to testing and vaccination availability, life expectancy will not rebound quickly, as has been seen historically elsewhere after intense shocks such as a pandemic or wars. They predict that the future demographic consequences for Brazil may be even more severe than those reported in their findings.