Department of Ecology and Evolution, University of Chicago, 1101 E 57th Street, Chicago, IL, 60637, USA.
WHO Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, The University of Hong Kong, Patrick Manson Building, 7 Sassoon Road, Pokfulam, Hong Kong, China.
Nat Commun. 2019 Apr 10;10(1):1660. doi: 10.1038/s41467-019-09652-6.
Influenza A viruses evolve rapidly to escape host immunity, causing reinfection. The form and duration of protection after each influenza virus infection are poorly understood. We quantify the dynamics of protective immunity by fitting individual-level mechanistic models to longitudinal serology from children and adults. We find that most protection in children but not adults correlates with antibody titers to the hemagglutinin surface protein. Protection against circulating strains wanes to half of peak levels 3.5-7 years after infection in both age groups, and wanes faster against influenza A(H3N2) than A(H1N1)pdm09. Protection against H3N2 lasts longer in adults than in children. Our results suggest that influenza antibody responses shift focus with age from the mutable hemagglutinin head to other epitopes, consistent with the theory of original antigenic sin, and might affect protection. Imprinting, or primary infection with a subtype, has modest to no effect on the risk of non-medically attended infections in adults.
甲型流感病毒迅速进化以逃避宿主免疫，导致再次感染。每次感染流感病毒后，保护的形式和持续时间尚不清楚。我们通过将个体水平的机械模型拟合到儿童和成人的纵向血清学数据，来量化保护性免疫的动态。我们发现，大多数保护作用（儿童中）但不是（成人中）与针对血凝素表面蛋白的抗体滴度相关。在感染后 3.5-7 年内，两组人群对流行株的保护作用均衰减至峰值水平的一半，而且对 A(H3N2)的衰减速度快于 A(H1N1)pdm09。成人对 H3N2 的保护作用比儿童更长。我们的研究结果表明，流感抗体反应随着年龄的增长而从易变的血凝素头部转移到其他表位，这与原始抗原性理论一致，并且可能影响保护作用。印迹（或亚株的初次感染）对成人非医疗相关感染的风险几乎没有影响。
