Ragona G, Giunchi G, Rocchi G, Muzzi A, De Felici A
J Hyg (Lond). 1978 Apr;80(2):249-57. doi: 10.1017/s0022172400053602.
Influenza activity was studied in the Rome population from 1956 to 1976 by analysis of mortality from respiratory causes and from all causes. During cold weather months, type A influenza virus was associated, as a rule, with epidemic excess deaths at two year intervals while type B virus was prevalent twice during isolation data were also compared with epidemic excess mortality during four consecutive years. The evidence obtained indicated that influenza virus isolation alone does not represent a reliable index of epidemic influenza activity in this population. The proportion of deaths attributed to respiratory causes consistently increased in every epidemic, the most pronounced increases occurring during large epidemics. The break-down by age of deaths from respiratory causes in the course of two epidemic periods showed that the percentage distribution of deaths was essentially the same as in non-epidemic periods. This evidence indicates that the same factors influencing the age-related distribution of mortality from respiratory causes during non-epidemic periods, probably affect the fatal outcome of influenza during epidemics.
通过分析呼吸道疾病及所有病因导致的死亡率，对1956年至1976年罗马人群中的流感活动情况进行了研究。在寒冷季节，通常每隔两年甲型流感病毒就会引发流行性超额死亡，而乙型流感病毒在隔离期间流行过两次，同时还将四年间的隔离数据与流行性超额死亡率进行了比较。所获证据表明，仅流感病毒分离情况并不能代表该人群中流行性流感活动的可靠指标。每次流行期间，呼吸道疾病导致的死亡比例持续上升，在大规模流行期间上升最为显著。两个流行期内呼吸道疾病死亡按年龄的分类显示，死亡的百分比分布与非流行期基本相同。这一证据表明，在非流行期影响呼吸道疾病死亡年龄分布的相同因素，可能也会影响流感流行期间的致命后果。
