The COVID-19 pandemic is a global public health crisis. However, little is known about the pathogenesis and biomarkers of COVID-19. Herein, we profiled host responses to COVID-19 by performing plasma proteomics of a cohort of COVID-19 patients including non-survivors and survivors recovered from mild or severe symptoms, and uncovered numerous COVID-19-associated alterations of plasma proteins. We developed a machine learning-based pipeline to identify 11 proteins as biomarkers and a set of biomarker combinations, which were validated by an independent cohort and accurately distinguished and predicted COVID-19 outcomes. Some of the biomarkers were further validated by ELISA using a larger cohort. These markedly altered proteins, including the biomarkers mediate pathophysiological pathways such as immune or inflammatory responses, platelet degranulation and coagulation, and metabolism, that likely contribute to the pathogenesis. Our findings provide valuable knowledge about COVID-19 biomarkers, and shed light on the pathogenesis and potential therapeutic targets of COVID-19.

Risk factors associated with disease severity and length of hospital stay in COVID-19 patients Dear Editor,We read with interest the article in this journal which revealed the critical role of timely supply of medical resources for COVID-19 patients. 1 The pandemic of COVID-19 has placed an enormous burden on health authorities across the world. The virus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2; previously known as 2019-nCoV), causes acute respiratory disease with common signs of infection being respiratory symptoms, fever, cough and breathing difficulties. In more severe cases, infection causes pneumonia, lung failure, septic shock, organ failure and risk of death. The WHO reports that 80% of those infected will develop mild symptoms, 14% severe symptoms and 6% will become critically ill. Given the wide clinical spectrum of COVID-19, a key challenge faced by frontline clinical staff is prioritisation of stretched resources. Thus, there is a critical need for robust risk assessment for clinical management.

Thyroid nodules are very common all over the world, and China is no exception. Ultrasound plays an important role in determining the risk stratification of thyroid nodules, which is critical for clinical management of thyroid nodules. For the past few years, many versions of TIRADS (Thyroid Imaging Reporting and Data System) have been put forward by several institutions with the aim to identify whether nodules require fine-needle biopsy or ultrasound follow-up. However, no version of TIRADS has been widely adopted worldwide till date. In China, as many as ten versions of TIRADS have been used in different hospitals nationwide, causing a lot of confusion. With the support of the Superficial Organ and Vascular Ultrasound Group of the Society of Ultrasound in Medicine of the Chinese Medical Association, the Chinese-TIRADS that is in line with China's national conditions and medical status was established based on literature review, expert consensus, and multicenter data provided by the Chinese Artificial Intelligence Alliance for Thyroid and Breast Ultrasound.