ABSTRACT
Messenger RNA(mRNA) vaccine, with antigen-encoded mRNA packaged in delivery vehicles, performs its functions via antigen translation and specific immune response. mRNA vaccines have proven their protective effects and safety in the ongoing COVID-19 pandemic caused by severe acute respiratory syndrome coronavirus 2(SARS-CoV-2). The World Health Organization issued guidelines specifically for prophylactic mRNA vaccines in 2021, which provide important guidance for non-clinical research on mRNA vaccines. Furthermore, some unusual adverse reactions, such as cerebrovascular disease, embolic stroke, transient cerebral ischemia, deep vein thrombosis, myocarditis(pericarditis) and allergic reactions, have been also found in clinical trials and applications of mRNA vaccines, which deserves attention in non-clinical studies.
ABSTRACT
Fundamental to viral biology is identification and annotation of viral genes and their function. Determining the level of coronavirus gene expression is inherently difficult due to the positive stranded RNA genome and the identification of subgenomic RNAs (sgRNAs) that are required for expression of most viral genes. We developed a bioinformatic pipeline to analyze metatranscriptomic data from 20 independent studies encompassing 588 individual samples and 10 coronavirus species. This comparative analysis defined a core sgRNA repertoire for SARS-CoV-2 and found novel sgRNAs that could encode functional short peptides. Relevant to coronavirus infectivity and transmission, we also observed that the ratio of Spike sgRNA to Nucleocapsid one is highest in SARS-CoV-2, among the ß-coronaviruses examined. Furthermore, the adjustment of this ratio can be made by modifications to the viral RNA replication machinery, representing a form of viral gene regulation that may be involved in host adaption.