The reproduction number of seasonal influenza epidemics in Brazil, 1996-2006
The reproduction number of seasonal influenza epidemics in Brazil, 1996-2006
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DOI：
10.1098/rspb.2009.1897
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发表时间：
2010-06-22
影响因子：
4.7
通讯作者：
Alonso, Wladimir J.
中科院分区：
文献类型：
--
作者：
Chowell, Gerardo;Viboud, Cecile;Alonso, Wladimir J.
对热带地区流感的传播动力学知之甚少。在这里，我们探讨的地理变化，在整个赤道，热带和亚热带地区的巴西，每周肺炎和流感（P&I）死亡率时间序列的分析的基础上，在27个州的流感繁殖数量。巴西的平均繁殖数（R）较低（平均值= 1.03（95%CI 1.02-1.04），假设连续间隔为3天）。巴西的繁殖数量估计值略低于美国或法国（平均差异R = 0.08，p < 0.01），并且显示出较小的年间变化（p < 0.001）。我们的研究结果表明，在人口规模的繁殖数量的弱梯度，其中R增加从低人口在北部的巴西南部的高人口。我们对繁殖数量的低估计表明，巴西的流感人群免疫力平均可能很高，这可能导致病毒遗传多样性增加和新变种的出现率增加。需要进行更多的流行病学和遗传学研究，以进一步描述热带地区流感的动态，并完善我们对流感病毒全球传播的理解。
The transmission dynamics of influenza in tropical regions are poorly understood. Here we explore geographical variations in the reproduction number of influenza across equatorial, tropical and subtropical areas of Brazil, based on the analysis of weekly pneumonia and influenza (P&I) mortality time series in 27 states. The reproduction number (R) was low on average in Brazil (mean = 1.03 (95% CI 1.02-1.04), assuming a serial interval of 3 days). Estimates of the reproduction number were slightly lower for Brazil than for the USA or France (difference in mean R = 0.08, p < 0.01) and displayed less between-year variation (p < 0.001). Our findings suggest a weak gradient in the reproduction number with population size, where R increases from low population in the North to high population in the South of Brazil. Our low estimates of the reproduction number suggest that influenza population immunity could be high on average in Brazil, potentially resulting in increased viral genetic diversity and rate of emergence of new variants. Additional epidemiological and genetic studies are warranted to further characterize the dynamics of influenza in the tropics and refine our understanding of the global circulation of influenza viruses.