Global trends in air travel: implications for connectivity and resilience to infectious disease threats

Ashleigh R Tuite; Deepit Bhatia; Rahim Moineddin; Isaac Bogoch; Alexander G Watts; Kamran Khan

The global population recently surpassed 7.6 billion people and is expected to reach 9.8 billion by 2050. 1 In tandem, transportation networks have expanded and evolved to satisfy the growing social and economic demands for global connectivity. 2 Today, commercial air travel is the conduit for approximately 3.5 billion trips annually, of which over 40% are international. 3 We live in an increasingly connected world, with more people traveling further distances than prior generations and decreased times required to travel these increased distances. 4 While this interconnectedness is a defining feature of globalization and has produced tremendous benefits for humankind, it has also facilitated the geographic dispersion of infectious diseases. 5 Although travel has always been associated with the introduction of pathogens to new environments and populations, the speed with which these new introductions occurs has been enhanced as population mobility increases. In the 1800s, the slow march of the second cholera pandemic could be observed to follow trade and military campaign routes out of India to Central Asia, the Middle East, Europe, and eventually North America, over the course of years. 5 Today, by contrast, infectious diseases can traverse the globe in less than a day. [6] [7] [8] With improvements in the availability of and access to various modes of transportation over the past several decades and the resultant decreases in time required to reach destinations, an outbreak in an isolated location can pose an international threat. 5 It is generally assumed that increased numbers of international travelers will increase global vulnerability to infectious diseases, by enhancing the potential for geographic spread. However, increased travel volume alone does not capture another . CC-BY-NC 4.0 International license It is made available under a author/funder, who has granted medRxiv a license to display the preprint in perpetuity.