Prior immunity helps to explain wave-like behaviour of pandemic influenza in 1918-9.
Prior immunity helps to explain wave-like behaviour of pandemic influenza in 1918-9.
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DOI：
10.1186/1471-2334-10-128
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发表时间：
2010-05-25
影响因子：
3.7
通讯作者：
McCaw JM
中科院分区：
文献类型：
--
作者：
Mathews JD;McBryde ES;McVernon J;Pallaghy PK;McCaw JM
流感的生态学可能比人们通常认为的要复杂得多。例如，尽管在1918- 1919年的流感大流行中出现了多波，但城市地区的许多人显然没有受到影响。他们是否未暴露于病毒，或者在第一波中受到预先存在的交叉免疫的保护，在后来的几波中受到获得性免疫的保护，或者他们的感染是无症状的？我们对所有这些可能性进行了建模，以估计参数，最好地解释1918- 1919年大流行期间12个英国人群中可能暴露于夏季，秋季和冬季浪潮的24，706人的重复攻击模式。在夏季浪潮之前，我们估计只有52%的人（95%的可信度估计为41-66%）是易感的，其余的人受到先前免疫力的保护。大多数人都接触了病毒，因为病毒传播性很高，R 0可信度估计值为3.10-6.74。由于先前的免疫力，在夏季波开始时的有效R估计值较低，为1.57-3.96。只有25-66%的接触者和易感者报告了症状。在每一波之后，33-65%的受保护者在下一波之前通过免疫力减弱或抗原漂移再次变得易感。年轻人群（19-59%）的既往免疫率估计值低于成年人群（38-66%），年轻人群（49-92%）的既往免疫率估计值低于成年人群（34-76%）。我们对1918- 1919年流感大流行的模型表明，预先存在的免疫保护，可能是由先前暴露于季节性流感引起的，可能限制了城市人群的大流行袭击率，而这种保护的减弱可能导致了暴露城市的大流行浪潮的复发。与此相反，在孤立的人群中，1918 ~ 1919年的流感大流行发病率远高于城市人群，这可能是因为以前很少接触季节性流感的人群的免疫力较低。虽然这些结论无法通过直接测量历史免疫机制来验证，但我们对1918- 1919年的建模推断表明，2009年甲型H1N1流感大流行的传播也受到先前暴露于季节性流感的免疫力的限制。这种免疫力的成分是可测量的，可能是短暂的，不一定与HI抗体水平相关。
The ecology of influenza may be more complex than is usually assumed. For example, despite multiple waves in the influenza pandemic of 1918-19, many people in urban locations were apparently unaffected. Were they unexposed, or protected by pre-existing cross-immunity in the first wave, by acquired immunity in later waves, or were their infections asymptomatic? We modelled all these possibilities to estimate parameters to best explain patterns of repeat attacks in 24,706 individuals potentially exposed to summer, autumn and winter waves in 12 English populations during the 1918-9 pandemic. Before the summer wave, we estimated that only 52% of persons (95% credibility estimates 41-66%) were susceptible, with the remainder protected by prior immunity. Most people were exposed, as virus transmissibility was high with R0 credibility estimates of 3.10-6.74. Because of prior immunity, estimates of effective R at the start of the summer wave were lower at 1.57-3.96. Only 25-66% of exposed and susceptible persons reported symptoms. After each wave, 33-65% of protected persons became susceptible again before the next wave through waning immunity or antigenic drift. Estimated rates of prior immunity were less in younger populations (19-59%) than in adult populations (38-66%), and tended to lapse more frequently in the young (49-92%) than in adults (34-76%). Our model for pandemic influenza in 1918-9 suggests that pre-existing immune protection, presumably induced by prior exposure to seasonal influenza, may have limited the pandemic attack-rate in urban populations, while the waning of that protection likely contributed to recurrence of pandemic waves in exposed cities. In contrast, in isolated populations, pandemic attack rates in 1918-9 were much higher than in cities, presumably because prior immunity was less in populations with infrequent prior exposure to seasonal influenza. Although these conclusions cannot be verified by direct measurements of historical immune mechanisms, our modelling inferences from 1918-9 suggest that the spread of the influenza A (H1N1) 2009 pandemic has also been limited by immunity from prior exposure to seasonal influenza. Components of that immunity, which are measurable, may be short-lived, and not necessarily correlated with levels of HI antibody.
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DOI：
10.1056/nejmoa0905498
发表时间：
2009-12-31
期刊：
The New England journal of medicine
影响因子：
--
作者：
Cauchemez S;Donnelly CA;Reed C;Ghani AC;Fraser C;Kent CK;Finelli L;Ferguson NM
通讯作者：
Ferguson NM
影响因子：
56.3
作者：
Bodewes, Rogier;Kreijtz, Joost H. C. M.;Rimmelzwaan, Guus F.
通讯作者：
Rimmelzwaan, Guus F.
影响因子：
64.8
作者：
Ferguson, NM;Galvani, AP;Bush, RM
通讯作者：
Bush, RM
DOI：
10.1073/pnas.0611071104
发表时间：
2007-05-01
影响因子：
11.1
作者：
Bootsma, Martin C. J.;Ferguson, Neil M.
通讯作者：
Ferguson, Neil M.
DOI：
10.1073/pnas.0601266103
发表时间：
2006-04-11
影响因子：
11.1
作者：
Germann, TC;Kadau, K;Macken, CA
通讯作者：
Macken, CA