ABSTRACT
The coronavirus disease 2019 (COVID-19) pandemic continues to pose substantial risks to public health, worsened by the emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants that may have a higher transmissibility and reduce vaccine effectiveness. We conducted a systematic review and meta-analysis on reproduction numbers of SARS-CoV-2 variants and provided pooled estimates for each variant.
Subject(s)
COVID-19 , SARS-CoV-2 , COVID-19/epidemiology , Humans , Pandemics , Reproduction , SARS-CoV-2/geneticsABSTRACT
Superspreading, or overdispersion in transmission, is a feature of SARS-CoV-2 transmission which results in surging epidemics and large clusters of infection. The dispersion parameter is a statistical parameter used to characterize and quantify heterogeneity. In the context of measuring transmissibility, it is analogous to measures of superspreading potential among populations by assuming that collective offspring distribution follows a negative-binomial distribution. We conducted a systematic review and meta-analysis on globally reported dispersion parameters of SARS-CoV-2 infection. All searches were carried out on 10 September 2021 in PubMed for articles published from 1 January 2020 to 10 September 2021. Multiple estimates of the dispersion parameter have been published for 17 studies, which could be related to where and when the data were obtained, in 8 countries (e.g. China, the United States, India, Indonesia, Israel, Japan, New Zealand and Singapore). High heterogeneity was reported among the included studies. The mean estimates of dispersion parameters range from 0.06 to 2.97 over eight countries, the pooled estimate was 0.55 (95% CI: 0.30, 0.79), with changing means over countries and decreasing slightly with the increasing reproduction number. The expected proportion of cases accounting for 80% of all transmissions is 19% (95% CrI: 7, 34) globally. The study location and method were found to be important drivers for diversity in estimates of dispersion parameters. While under high potential of superspreading, larger outbreaks could still occur with the import of the COVID-19 virus by traveling even when an epidemic seems to be under control.
Subject(s)
COVID-19 , Epidemics , Animals , COVID-19/epidemiology , COVID-19/veterinary , China/epidemiology , India , SARS-CoV-2ABSTRACT
The coronavirus disease 2019 (COVID-19) pandemic continues to pose substantial risks to public health, worsened by the emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants that may have a higher transmissibility and reduce vaccine effectiveness. We conducted a systematic review and meta-analysis on reproduction numbers of SARS-CoV-2 variants and provided pooled estimates for each variant.
Subject(s)
COVID-19 , SARS-CoV-2 , COVID-19/epidemiology , Humans , Pandemics , Reproduction , SARS-CoV-2/geneticsABSTRACT
The COVID-19 pandemic caused by SARS-CoV-2 has become a global threat. Understanding the underlying mechanisms and developing innovative treatments are extremely urgent. G-quadruplexes (G4s) are important noncanonical nucleic acid structures with distinct biofunctions. Four putative G4-forming sequences (PQSs) in the SARS-CoV-2 genome were studied. One of them (RG-1), which locates in the coding sequence region of SARS-CoV-2 nucleocapsid phosphoprotein (N), has been verified to form a stable RNA G4 structure in live cells. G4-specific compounds, such as PDP (pyridostatin derivative), can stabilize RG-1 G4 and significantly reduce the protein levels of SARS-CoV-2 N by inhibiting its translation both in vitro and in vivo. This result is the first evidence that PQSs in SARS-CoV-2 can form G4 structures in live cells, and that their biofunctions can be regulated by a G4-specific stabilizer. This finding will provide new insights into developing novel antiviral drugs against COVID-19.