Healthcare Analysis & Forecasting, Wantage OX12 0NE, UK.
Department of Biophysics, Informatics and Medical Instrumentation, Odessa National Medical University, Valikhovsky Lane 2, 65082 Odessa, Ukraine.
Int J Environ Res Public Health. 2022 Mar 14;19(6):3407. doi: 10.3390/ijerph19063407.
Trends in excess winter mortality (EWM) were investigated from the winter of 1900/01 to 2019/20. During the 1918-1919 Spanish flu epidemic a maximum EWM of 100% was observed in both Denmark and the USA, and 131% in Sweden. During the Spanish flu epidemic in the USA 70% of excess winter deaths were coded to influenza. EWM steadily declined from the Spanish flu peak to a minimum around the 1960s to 1980s. This decline was accompanied by a shift in deaths away from the winter and spring, and the EWM calculation shifted from a maximum around April to June in the early 1900s to around March since the late 1960s. EWM has a good correlation with the number of estimated influenza deaths, but in this context influenza pandemics after the Spanish flu only had an EWM equivalent to that for seasonal influenza. This was confirmed for a large sample of world countries for the three pandemics occurring after 1960. Using data from 1980 onward the effect of influenza vaccination on EWM were examined using a large international dataset. No effect of increasing influenza vaccination could be discerned; however, there are multiple competing forces influencing EWM which will obscure any underlying trend, e.g., increasing age at death, multimorbidity, dementia, polypharmacy, diabetes, and obesity-all of which either interfere with vaccine effectiveness or are risk factors for influenza death. After adjusting the trend in EWM in the USA influenza vaccination can be seen to be masking higher winter deaths among a high morbidity US population. Adjusting for the effect of increasing obesity counteracted some of the observed increase in EWM seen in the USA. Winter deaths are clearly the outcome of a complex system of competing long-term trends.
从 1900/01 年冬季到 2019/20 年冬季，研究了超额冬季死亡率（EWM）的趋势。在 1918-1919 年西班牙流感大流行期间，丹麦和美国的 EWM 最高达到 100%，瑞典达到 131%。在美国的西班牙流感大流行期间，70%的超额冬季死亡归因于流感。从西班牙流感高峰到 20 世纪 60 年代至 80 年代，EWM 稳步下降。这一下降伴随着死亡从冬季和春季转移，EWM 计算从 20 世纪初 4 月至 6 月左右的最大值转移到 20 世纪 60 年代后期左右的 3 月左右。EWM 与估计的流感死亡人数密切相关，但在这种情况下，西班牙流感后的流感大流行的 EWM 仅相当于季节性流感。这一点在 20 世纪 60 年代以后发生的三大流行中，对大量世界国家的样本进行了证实。使用 1980 年以后的数据，使用大型国际数据集检查了流感疫苗接种对 EWM 的影响。没有发现流感疫苗接种增加的效果；然而，有多种相互竞争的力量影响 EWM，这将掩盖任何潜在的趋势，例如，死亡年龄增加、多种合并症、痴呆、多种药物治疗、糖尿病和肥胖——所有这些都干扰疫苗的有效性或成为流感死亡的危险因素。在美国调整 EWM 的趋势后，可以看出流感疫苗接种掩盖了高发病率美国人群中冬季死亡人数的增加。调整肥胖率的增加，抵消了美国观察到的 EWM 增加的一部分。冬季死亡显然是一个复杂的竞争长期趋势的结果。
