Human birth seasonality: latitudinal gradient and interplay with childhood disease dynamics

More than a century of ecological studies have demonstrated the importance of demography in shaping spatial and temporal variation in population dynamics. Surprisingly, the impact of seasonal recruitment on infectious disease systems has received much less attention. Here, we present data encompassing 78 years of monthly natality in the USA, and reveal pronounced seasonality in birth rates, with geographical and temporal variation in both the peak birth timing and amplitude. The timing of annual birth pulses followed a latitudinal gradient, with northern states exhibiting spring/summer peaks and southern states exhibiting autumn peaks, a pattern we also observed throughout the Northern Hemisphere. Additionally, the amplitude of United States birth seasonality was more than twofold greater in southern states versus those in the north. Next, we examined the dynamical impact of birth seasonality on childhood disease incidence, using a mechanistic model of measles. Birth seasonality was fou...

一个多世纪以来的生态学研究均已证实，种群统计学（demography）在塑造种群动态的时空变异中发挥着核心作用。令人意外的是，季节性种群补充（seasonal recruitment）对传染病系统的影响却未受到足够的学术关注。本研究整合了美国78年间的月度出生数据，揭示了出生率存在显著的季节周期性，且峰值出现时间与波动幅度均存在地理与时间维度上的变异。年度集中出生时段的出现时间呈现纬度梯度特征：北部各州的出生峰值集中于春夏季，南部各州则集中于秋季，这一模式在整个北半球均有观测到。此外，美国南部各州的出生季节波动幅度较北部各州高出一倍以上。随后，本研究借助麻疹机制模型（mechanistic model），探究了出生季节周期性对儿童传染病发病率的动态影响。出生季节周期性的……