In this paper, heterogeneity is formally defined, and its properties are explored. We define and distinguish observable versus non-observable heterogeneity. It is proposed that heterogeneity among the vulnerable is a significant factor in the contagion impact of COVID-19, as demonstrated with incidence rates on a Diamond Princess Cruise ship in February 2020. Given the nature of the disease, its heterogeneity and human social norms, pre-voyage and post-voyage quick testing procedures may become the new standard for cruise ship passengers and crew. The technological advances in testing available today would facilitate more humanistic treatment as compared to more archaic quarantine and isolation practices for all onboard ship. With quick testing, identification of those infected and thus not allowed to embark on a cruise or quarantining those disembarking and other mitigation strategies, the popular cruise adventure could be available safely again. Whatever the procedures implemented, the methodological purpose of this study should add valuable insight in the modeling of disease and specifically, the COVID-19 virus.

中文翻译：

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异质性与COVID-19大流行

本文正式定义了异质性，并探讨了其性质。我们定义和区分可观察的和不可观察的异质性。据提议，脆弱人群之间的异质性是影响COVID-19传播的重要因素，如2020年2月一艘钻石公主号邮轮的发病率所证明的。鉴于该疾病的性质，异质性和人类社会规范，航行前和航行后快速测试程序可能成为游轮乘客和乘员的新标准。与所有船上较旧的检疫和隔离实践相比，当今可用的测试技术进步将促进更加人道的处理。通过快速测试，识别出受感染者，从而不允许其进行巡航或隔离那些下船策略和其他缓解策略，可以再次安全地使用流行的巡航冒险。无论采用何种程序，本研究的方法论目的均应为疾病建模（尤其是COVID-19病毒）建模增加有价值的见解。