Background COVID-19 is a novel and highly virulent virus, which caused a rapid and massive onset of clinical trials in a short period of time.With the aim to obtain suggestions in the guidance on performing public health emergency clinical trials, and control this virus in China and other countries and for the prevention of the onset of other infectious viruses in the future. Methods COVID-19, SARS, MERS and Ebola clinical trials registered in the Chinese clinical trial registry and clinical trials.gov were collected and analyzed and intervention protocols were descriptively analyzed, focusing on the analysis and comparison of the drug used. The search period ended on February 24, 2020. Results The number of the registered COVID-19 clinical trials was 295. Among 203 intervention trials, 78.3% (159) were drug clinical trials. The 159 COVID-19 trials were designed and analyzed with the highest proportion of random, open control study [66.0% (105)], and blind randomized trials [13.8% (22)]. The drug mostly used was Lopinavir/Ritonavir (15.1%). The sample size median 100,IQR(interquartile range) 140. The number of the registered SARS was 6, MERS 15, and Ebola 97. Among 3 MERS and 19 Ebola drug intervention clinical trials, MERS and Ebola were randomized, blind, and placebo-controlled drug clinical trials accounting for 100% (3) and 31.6% (6), respectively, while SARS were vaccine trials, without drug intervention clinical trials registered. Conclusions Some of the COVID-19 clinical trials and drug selection performed are somewhat disordered, requiring greater attention to the needs, science assumptions, ethics and quality management of the clinical research. Thus, during the epidemic period, the country should deliver guidance on how to perform appropriate emergency clinical trials, design a scientifically based clinical trial program and focus on researching drugs or vaccines that have great potential.

Since its identification in April 2009 an A(H1N1) virus containing a unique combination of gene segments from both North American and Eurasian swine lineages has continued to circulate in humans. The 2009 A(H1N1) virus is distantly related to its nearest relatives, indicating that its gene segments have been circulating undetected for an extended period. Low genetic diversity among the viruses suggests the introduction into humans was a single event or multiple events of similar viruses. Molecular markers predicted for adaptation to humans are not currently present in 2009 A(H1N1) viruses, suggesting previously unrecognized molecular determinants could be responsible for the transmission among humans. Antigenically the viruses are homogeneous and similar to North American swine A(H1N1) viruses but distinct from seasonal human A(H1N1).

During the evaluation period, 2009 H1N1 influenza caused severe illness requiring hospitalization, including pneumonia and death. Nearly three quarters of the patients had one or more underlying medical conditions. Few severe illnesses were reported among persons 65 years of age or older. Patients seemed to benefit from antiviral therapy.

A novel swine-origin influenza A virus was identified as the cause of outbreaks of febrile respiratory infection ranging from self-limited to severe illness. It is likely that the number of confirmed cases underestimates the number of cases that have occurred.

Centers for Disease Control and Prevention.