The most important characteristics of coronavirus disease 2019 (COVID-19) transmission that makes it difficult to control are 1) asymptomatic and presymptomatic transmission, 2) low incidence or lack of dominant systemic symptoms such as fever, 3) airborne transmission that may need a high infectious dose, and 4) super-spread events (SSEs). Patients with COVID-19 have high viral loads at symptom onset or even a few days prior to symptom onset, and most patients with COVID-19 have only mild respiratory symptoms or merely pauci-/null-symptoms. These characteristics of the virus enable it to easily spread to the community because most patients are unaware of their potential infectivity, and symptom-based control measures cannot prevent this type of transmission. Furthermore, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is also capable of airborne transmission in conditions such as aerosol-generating procedures, under-ventilated indoor spaces, and over-crowded areas. In this context, universal mask-wearing is important to prevent both outward and inward transmission until an adequate degree of herd immunity is achieved through vaccination. Lastly, the SSEs of SARS-CoV-2 transmission emphasize the importance of reducing contacts by limiting social gatherings. The above-mentioned transmission characteristics of SARS-CoV-2 have culminated in the failure of long-lasting quarantine measures, and indicate that only highly effective vaccines can keep the communities safe from this deadly, multifaceted virus.

中文翻译：

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阻碍有效控制的SARS-CoV-2的传输特性。

导致难以控制的2019年冠状病毒病（COVID-19）传播的最重要特征是1）无症状和症状前传播，2）低发率或缺乏全身性症状，例如发烧，3）可能需要通过空气传播的空中传播高感染剂量，以及4）超级传播事件（SSE）。具有COVID-19的患者在症状发作时甚至在症状发作前几天都有较高的病毒载量，大多数COVID-19的患者只有轻度的呼吸道症状或仅有脓性/无效症状。病毒的这些特征使它易于传播给社区，因为大多数患者都不知道其潜在的传染性，并且基于症状的控制措施无法阻止这种类型的传播。此外，严重的急性呼吸系统综合症冠状病毒2（SARS-CoV-2）还能够在气溶胶生成程序，室内通风不足和人满为患的条件下通过空气传播。在这种情况下，普遍佩戴口罩很重要，以防止向外和向内传播，直到通过疫苗接种获得足够程度的牛群免疫。最后，SARS-CoV-2传播的SSE强调通过限制社交聚会来减少联系的重要性。SARS-CoV-2的上述传播特征最终导致了长期隔离措施的失败，并表明只有高效的疫苗才能使社区免受这种致命的多面性病毒的侵害。通风不良的室内空间和人满为患的区域。在这种情况下，普遍佩戴口罩很重要，以防止向外和向内传播，直到通过疫苗接种获得足够程度的牛群免疫。最后，SARS-CoV-2传播的SSE强调通过限制社交聚会来减少联系的重要性。SARS-CoV-2的上述传播特征最终导致了长期隔离措施的失败，并表明只有高效的疫苗才能使社区免受这种致命的多面性病毒的侵害。通风不良的室内空间和人满为患的区域。在这种情况下，普遍佩戴口罩很重要，以防止向外和向内传播，直到通过疫苗接种获得足够程度的牛群免疫。最后，SARS-CoV-2传播的SSE强调通过限制社交聚会来减少联系的重要性。SARS-CoV-2的上述传播特征最终导致了长期隔离措施的失败，并表明只有高效的疫苗才能使社区免受这种致命的多面性病毒的侵害。SARS-CoV-2传播的SSE强调通过限制社交聚会来减少联系的重要性。SARS-CoV-2的上述传播特征最终导致了长期隔离措施的失败，并表明只有高效的疫苗才能使社区免受这种致命的多面性病毒的侵害。SARS-CoV-2传播的SSE强调通过限制社交聚会来减少联系的重要性。SARS-CoV-2的上述传播特征最终导致了长期隔离措施的失败，并表明只有高效的疫苗才能使社区免受这种致命的多面性病毒的侵害。