Patrozou Eleni, Mermel Leonard A
Division of Infectious Diseases, Department of Medicine, Warren Alpert Medical School of Brown University, Providence, RI, USA.
Public Health Rep. 2009 Mar-Apr;124(2):193-6. doi: 10.1177/003335490912400205.
A better understanding of transmission dynamics is essential in influenza pandemic planning. If a substantial proportion of transmissions were to occur during the presymptomatic phase or from asymptomatic individuals, then infection control measures such as contact tracing and quarantine of exposures would be of limited value. Infectiousness has been inferred based on the presence of influenza in the upper respiratory tract rather than from transmission experiments. Although asymptomatic individuals may shed influenza virus, studies have not determined if such people effectively transmit influenza. We performed a systematic review of published studies describing the relationship between viral shedding and disease transmission. Based on the available literature, we found that there is scant, if any, evidence that asymptomatic or presymptomatic individuals play an important role in influenza transmission. As such, recent articles concerning pandemic planning, some using transmission modeling, may have overestimated the effect of presymptomatic or asymptomatic influenza transmission. More definitive transmission studies are sorely needed.
更好地理解传播动态对于流感大流行规划至关重要。如果相当一部分传播发生在症状出现前阶段或来自无症状个体，那么诸如接触者追踪和暴露后检疫等感染控制措施的价值将有限。传染性是根据上呼吸道中流感病毒的存在推断出来的，而非基于传播实验。虽然无症状个体可能会排出流感病毒，但研究尚未确定这些人是否能有效传播流感。我们对已发表的描述病毒排出与疾病传播之间关系的研究进行了系统综述。基于现有文献，我们发现几乎没有证据表明无症状或症状出现前个体在流感传播中起重要作用。因此，近期一些关于大流行规划的文章，有些使用了传播模型，可能高估了症状出现前或无症状流感传播的影响。迫切需要更确切的传播研究。
