KwaZulu-Natal Research Innovation and Sequencing Platform (KRISP), Nelson R. Mandela School of Medicine, University of KwaZulu-Natal, Durban, South Africa.
Centre for Epidemic Response and Innovation (CERI), School of Data Science and Computational Thinking, Stellenbosch University, Stellenbosch, South Africa.
J Travel Med. 2022 Dec 27;29(8). doi: 10.1093/jtm/taac134.
Human mobility changed in unprecedented ways during the SARS-CoV-2 pandemic. In March and April 2020, when lockdowns and large travel restrictions began in most countries, global air-travel almost entirely halted (92% decrease in commercial global air travel in the months between February and April 2020). Initial recovery in global air travel started around July 2020 and subsequently nearly tripled between May and July 2021. Here, we aim to establish a preliminary link between global mobility patterns and the synchrony of SARS-CoV-2 epidemic waves across the world.
We compare epidemic peaks and human global mobility in two time periods: November 2020 to February 2021 (when just over 70 million passengers travelled) and November 2021 to February 2022 (when more than 200 million passengers travelled). We calculate the time interval during which continental epidemic peaks occurred for both of these time periods, and we calculate the pairwise correlations of epidemic waves between all pairs of countries for the same time periods.
We find that as air travel increases at the end of 2021, epidemic peaks around the world are more synchronous with one another, both globally and regionally. Continental epidemic peaks occur globally within a 20 day interval at the end of 2021 compared with 73 days at the end of 2020, and epidemic waves globally are more correlated with one another at the end of 2021.
This suggests that the rebound in human mobility dictates the synchrony of global and regional epidemic waves. In line with theoretical work, we show that in a more connected world, epidemic dynamics are more synchronized.
在 SARS-CoV-2 大流行期间，人类的流动性以前所未有的方式发生了变化。2020 年 3 月和 4 月，当大多数国家开始实施封锁和大规模旅行限制时，全球航空旅行几乎完全停止（2020 年 2 月至 4 月间，商业全球航空旅行减少了 92%）。全球航空旅行的初步复苏始于 2020 年 7 月左右，随后在 2021 年 5 月至 7 月期间几乎翻了三倍。在这里，我们旨在建立全球流动模式与全球 SARS-CoV-2 疫情波之间的初步联系。
我们将 2020 年 11 月至 2021 年 2 月（当时只有超过 7000 万名乘客出行）和 2021 年 11 月至 2022 年 2 月（当时有超过 2 亿名乘客出行）这两个时间段的疫情高峰期和全球人类流动进行比较。我们计算了这两个时间段内大陆疫情高峰期发生的时间间隔，并且计算了同一时间段内所有国家之间疫情波的两两相关性。
我们发现，随着 2021 年底航空旅行的增加，世界各地的疫情高峰期更加同步，无论是在全球范围内还是在区域范围内。与 2020 年底的 73 天相比，2021 年底全球范围内的大陆疫情高峰期在 20 天的时间间隔内发生，并且全球范围内的疫情波更加相关。
这表明人类流动性的反弹决定了全球和区域疫情波的同步性。与理论工作一致，我们表明在一个联系更加紧密的世界中，疫情动态更加同步。
