Poulain Michel, Chambre Dany, Pes Giovanni Mario
IACCHOS Université Catholique de Louvain, Louvain-la-Neuve, Belgium.
Estonian Institute for Population Studies, Tallinn University, Tallinn, Estonia.
Aging (Albany NY). 2021 Sep 27;13(18):21855-21865. doi: 10.18632/aging.203577.
Although it is known that mortality due to COVID-19 increases progressively with age, the probability of dying from this serious infection among the oldest-old population is little known, and controversial data are found in literature.
We examine the mortality by year and month of birth of Belgians who had turned 100 during the current COVID-19 pandemic and whose birth fell on the years around the end the First World War and the outbreak of the H1N1 "Spanish flu" pandemic.
The COVID-19 mortality of the "older" centenarians is significantly lower than that of "younger" centenarians, and this difference between the two groups reaches a maximum on August 1, 1918 as the discriminating cut-off date of birth. Having excluded the plausible impact of the end of WWI it becomes clear that this date corresponds to the time of reporting the first victims of the Spanish flu pandemic in Belgium.
In this study, the striking temporal coincidence between the outbreak of the Spanish flu epidemic and the birth of the cohorts characterized by greater fragility towards COVID-19 in 2020 strongly suggests a link between exposure to 1918 H1N1 pandemic influenza and resistance towards 2020 SARS-Cov-2. It can be speculated that the lifetime persistence of cross-reactive immune mechanisms has enabled centenarians exposed to the Spanish flu to overcome the threat of COVID-19 a century later.
尽管已知新冠病毒疾病（COVID-19）导致的死亡率随年龄增长而逐渐上升，但关于最年长者群体死于这种严重感染的概率却鲜为人知，且文献中存在有争议的数据。
我们研究了在当前COVID-19大流行期间年满100岁、出生于第一次世界大战末期和H1N1“西班牙流感”大流行爆发前后几年的比利时人的按出生年份和月份划分的死亡率。
“年长”的百岁老人的COVID-19死亡率显著低于“年轻”的百岁老人，两组之间的这种差异在1918年8月1日作为区分出生的截止日期时达到最大。排除第一次世界大战结束的合理影响后，很明显这个日期对应于比利时报告西班牙流感大流行首批受害者的时间。
在本研究中，西班牙流感疫情的爆发与2020年对COVID-19表现出更大脆弱性的队列人群的出生时间之间惊人的时间巧合，强烈表明接触1918年H1N1大流行性流感与对2020年严重急性呼吸综合征冠状病毒2（SARS-CoV-2）的抵抗力之间存在联系。可以推测，交叉反应性免疫机制的终生持续存在使接触过西班牙流感的百岁老人能够在一个世纪后抵御COVID-19的威胁。
