Dalla Lana School of Public Health, University of Toronto, Toronto, ON, Canada.
Epidemiol Infect. 2010 Nov;138(11):1542-9. doi: 10.1017/S0950268810000579. Epub 2010 Mar 22.
The world is currently confronting the first influenza pandemic of the 21st century [caused by a novel pandemic influenza A (H1N1) virus]. Earlier pandemics have been characterized by age distributions that are distinct from those observed with seasonal influenza epidemics, with higher attack rates (and correspondingly increased proportionate or relative mortality) in younger individuals. While the genesis of protection against infection in older individuals during a pandemic is uncertain, differential vulnerability to infection by age has important implications for disease dynamics and control, and for choice of optimal vaccination strategies. Age-related vulnerability to infection may explain differences between school- and community-derived estimates of the reproductive number (R) for a newly emerged pandemic strain, and may also help explain the failure of a newly emerged influenza A (H1N1) virus strain to cause a pandemic in 1977. Age-related factors may also help explain variability in attack rates, and the size and impact of influenza epidemics across jurisdictions and between populations. In Canada, such effects have been observed in the apparently increased severity of outbreaks on Indigenous peoples' reserves. The implications of these patterns for vaccine allocation necessitate targeted research to understand age-related vulnerabilities early in an influenza pandemic.
目前，世界正面临着 21 世纪的第一次流感大流行[由新型大流行流感 A(H1N1)病毒引起]。早期的大流行具有不同于季节性流感流行的年龄分布特征，年轻人的发病率（相应增加的比例或相对死亡率）更高。虽然在大流行期间，老年人对感染的保护机制尚不清楚，但年龄对感染的易感性差异对疾病动态和控制以及最佳疫苗接种策略的选择具有重要意义。年龄相关的易感性可能解释了新出现的大流行菌株在学校和社区中估计的繁殖数（R）之间的差异，也可能有助于解释 1977 年新出现的甲型流感（H1N1）病毒株为何未能引发大流行。年龄相关因素也可能有助于解释在不同司法管辖区和人群之间发病率、流感流行的规模和影响的差异。在加拿大，在原住民保留地爆发的疫情明显加重的情况下，观察到了这些影响。这些模式对疫苗分配的影响需要有针对性的研究，以便在流感大流行早期了解与年龄相关的脆弱性。
