RETRACTED ARTICLE:Human H9N2 Avian Influenza Infection:Epidemiological and Clinical Characterization of 16 Cases in China

The authors are retracting this paper owing to errors in the reported data.The paper claimed that 16 patient cases were infected with H9N2 virus.However,when the authors recently further investigated all the thirteen sera samples,no anti-H9N2 antibodies were found by the haemagglutination inhibition assay.Moreover,re-sequencing of the remaining five throat swabs showed all five samples were H1N1 virus.

Ecology of avian influenza viruses in migratory birds wintering within the Yangtze River wetlands

Migratory birds are considered natural reservoirs of avian influenza A viruses(AIVs).To further our viral ecology knowledge and understand the subsequent risk posed by wild birds,we conducted a 4-year surveillance study of AIVs in the bird wintering wetlands of the Yangtze River,China.We collected over8000 samples and isolated 122 AIV strains.Analyses were then carried out with 108 novel sequenced genomes and data were deposited in GISAID and other public databases.The results showed that the Yangtze River wintering wetlands functioned as a mixing ground,where various subtypes of AIVs were detected harboring a high diversity of nucleotide sequences;moreover,a portion of AIV gene segments were persistent inter-seasonally.Phylogenetic incongruence presented complex reassortment events and distinct patterns among various subtypes.In addition,we observed that viral gene segments in wintering wetlands were closely related to known North American isolates,indicating that intercontinental gene flow occurred.Notably,highly pathogenic H5 and low pathogenic H9 viruses,which usually circulate in poultry,were found to have crossed the poultry/wild bird interface,with the viruses introduced to wintering birds.Overall,this study represented the largest AIV surveillance effort of wild birds within the Yangtze River wintering wetlands.Surveillance data highlighted the important role of wintering wild birds in the ecology of AIVs and may enable future early warnings of novel AIV emergence.

Low Pathogenic Avian Influenza A(H5N7) Virus Isolated from a Domestic Duck in Dongting Lake Wetland of China,2016

Dear Editor,The avian influenza virus (AIV) H5N7 was first isolated from wild birds in North America in 2001 (Spackman et al.2007), and information on only 25 strains of this virus has been deposited in the Global Initiative on Sharing All Influenza Data (GISAID-http://platform.gisaid.org/epi3/frontend#493de3) database until October 30, 2018. Twenty viruses were identified in the United States from 2001 to2017.

Avian influenza A(H7N9)virus:from low pathogenic to highly pathogenic

OriginalTranslation The avian influenza A(H7N9)virus is a zoonotic virus that is closely associated with live poultry markets.It has caused infections in humans in China since 2013.Five waves of the H7N9 influenza epidemic occurred in China between March 2013 and September 2017.H7N9 with low-pathogenicity dominated in the first four waves,whereas highly pathogenic H7N9 influenza emerged in poultry and spread to humans during the fifth wave,causing wide concern.Specialists and officials from China and other countries responded quickly,controlled the epidemic well thus far,and characterized the virus by using new technologies and surveillance tools that were made possible by their preparedness efforts.Here,we review the characteristics of the H7N9 viruses that were identified while controlling the spread of the disease.It was summarized and discussed from the perspectives of molecular epidemiology,clinical features,virulence and pathogenesis,receptor binding,T-cell responses,monoclonal antibody development,vaccine development,and disease burden.These data provide tools for minimizing the future threat of H7N9 and other emerging and re-emerging viruses,such as SARS-CoV-2.

Rapid and accurate identification of SARS-CoV-2 variants containing E484 mutation

The ongoing coronavirus disease 2019(COVID-19)pandemic caused by severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)infection has led to over 240 million confirmed infections and severe economic burdens worldwide.Multiple emerging SARS-CoV-2 variants of concern(VOCs)and variants of interest(VOIs)have recently beenidentifiedand are nowspreading internationally,including B.1.1.7(Alpha),B.1.351(Beta),P.1(Gamma),B.1.617(Delta and Kappa),C.37(Lambda),and B.1.621(Mu),all of which appear to bemore easily transmitted(WHO,COVID-19Weekly EpidemiologicalUpdate).Beta andGamma VOCs can seriously impair the protective efficacy of existing vaccines,potentially precluding the possibility of attaining"herd immunity."

Structural basis for the inhibition of the SARS-CoV-2 main protease by the anti-HCV drug narlaprevir

Dear Editor,The second wave of the coronavirus disease(COVID-19)pandemic has recently appeared in Europe.Most European countries,such as France,Germany,and Italy,have announced the implementation of a new round of epidemic prevention and control measures.However,no clinical drug or vaccine has been approved for the treatment of COVID-19.The interim results of the solidarity therapy trial coordinated by the World Health Organization(WHO)indicated that remdesivir,hydroxychloroquine,lopina-vir/ritonavir,and interferon appear to have little or no effect on the 28-day mortality of hospitalized patients or the hospitalization process of new COVID-19 patients.Therefore,there is an urgent need to develop new drugs against COVID-19.

A recombinant receptor-binding domain in trimeric form generates protective immunity against SARSCoV-2 infection in nonhuman primates

A safe and effective vaccine is critical to combat the COVID-19 pandemic.Here,we developed a trimeric SARS-CoV-2 receptor-binding domain(RBD)subunit vaccine candidate that simulates the natural structure of the spike(S)trimer glycoprotein.Immunization with the RBD trimer-induced robust humoral and cellular immune responses,and a high level of neutralizing antibodies was maintained for at least 4.5 months.Moreover,the antibodies that were produced in response to the vaccine effectively cross-neutralized the SARS-CoV-2501Y.V2 variant(B.1.351).Of note,when the vaccine-induced antibodies dropped to a sufficiently low level,only one boost quickly activated the anamnestic immune response,conferring full protection against a SARSCoV-2 challenge in rhesus macaques without typical histopathological changes in the lung tissues.These results demonstrated that the SARS-CoV-2 RBD trimer vaccine candidate is highly immunogenic and safe,providing long-lasting,broad,and significant immunity protection in nonhuman primates,thereby offering an optimal vaccination strategy against COVID-19.