PDF(Pubmed)
Abstract：
Symptom propagation occurs when the symptom set an individual experiences is correlated with the symptom set of the individual who infected them. Symptom propagation may dramatically affect epidemiological outcomes, potentially causing clusters of severe disease. Conversely, it could result in chains of mild infection, generating widespread immunity with minimal cost to public health. Despite accumulating evidence that symptom propagation occurs for many respiratory pathogens, the underlying mechanisms are not well understood. Here, we conducted a scoping literature review for 14 respiratory pathogens to ascertain the extent of evidence for symptom propagation by two mechanisms: dose-severity relationships and route-severity relationships. We identify considerable heterogeneity between pathogens in the relative importance of the two mechanisms, highlighting the importance of pathogen-specific investigations. For almost all pathogens, including influenza and SARS-CoV-2, we found support for at least one of the two mechanisms. For some pathogens, including influenza, we found convincing evidence that both mechanisms contribute to symptom propagation. Furthermore, infectious disease models traditionally do not include symptom propagation. We summarize the present state of modelling advancements to address the methodological gap. We then investigate a simplified disease outbreak scenario, finding that under strong symptom propagation, isolating mildly infected individuals can have negative epidemiological implications.
摘要：
当个体经历的症状集与感染它们的个体的症状集相关时，就会发生症状传播。症状传播可能会极大地影响流行病学结果，可能导致严重疾病的集群。相反，它可能会导致一连串的轻度感染，以最小的公共卫生成本产生广泛的免疫力。尽管越来越多的证据表明许多呼吸道病原体会出现症状传播，潜在的机制还没有得到很好的理解。这里,我们对14种呼吸道病原体进行了范围研究文献综述,以通过两种机制确定症状传播的证据范围:剂量-严重程度关系和途径-严重程度关系.我们在两种机制的相对重要性中确定了病原体之间的相当大的异质性，强调病原体特异性调查的重要性。几乎所有的病原体,包括流感和SARS-CoV-2，我们发现这两种机制中至少有一种得到支持。对于一些病原体，包括流感,我们发现有说服力的证据表明这两种机制都有助于症状的传播.此外，传染病模型传统上不包括症状传播。我们总结了建模进步的现状，以解决方法上的差距。然后我们调查一个简化的疾病爆发情景，发现在强烈的症状传播下，隔离轻度感染的个体可能会对流行病学产生负面影响。
