Omicron SARS-CoV-2 variant: a new chapter in the COVID-19 pandemic

The Lancet, Journal Year: 2021, Volume and Issue: 398(10317), P. 2126 - 2128

Published: Dec. 1, 2021

Language: Английский

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SARS-CoV-2 viral load and shedding kinetics

Nature Reviews Microbiology, Journal Year: 2022, Volume and Issue: unknown

Published: Dec. 2, 2022

Language: Английский

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A bacterial extracellular vesicle‐based intranasal vaccine against SARS‐CoV‐2 protects against disease and elicits neutralizing antibodies to wild‐type and Delta variants

Journal of Extracellular Vesicles, Journal Year: 2022, Volume and Issue: 11(3)

Published: March 1, 2022

Several vaccines have been introduced to combat the coronavirus infectious disease-2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome 2 (SARS-CoV-2). Current SARS-CoV-2 include mRNA-containing lipid nanoparticles or adenoviral vectors that encode Spike (S) protein of SARS-CoV-2, inactivated virus, subunits. Despite growing success in worldwide vaccination efforts, additional capabilities may be needed future address issues such as stability and storage requirements, need for vaccine boosters, desirability different routes administration, emergence variants Delta variant. Here, we present a novel, well-characterized candidate based on extracellular vesicles (EVs) Salmonella typhimurium are decorated with mammalian cell culture-derived receptor-binding domain (RBD). RBD-conjugated outer membrane (RBD-OMVs) were used immunize golden Syrian hamster (Mesocricetus auratus) model COVID-19. Intranasal immunization resulted high titres blood anti-RBD IgG well detectable mucosal responses. Neutralizing antibody activity against wild-type was evident all vaccinated subjects. Upon challenge live hamsters immunized RBD-OMV, but not animals unconjugated OMVs vehicle control, avoided body mass loss, had lower virus bronchoalveolar lavage fluid, experienced less lung pathology. Our results emphasize value versatility OMV-based approaches.

Language: Английский

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The displacement of the SARS-CoV-2 variant Delta with Omicron: An investigation of hospital admissions and upper respiratory viral loads

EBioMedicine, Journal Year: 2022, Volume and Issue: 79, P. 104008 - 104008

Published: April 20, 2022

The increase in SARS-CoV-2 infections December 2021 was driven primarily by the Omicron variant, which largely displaced Delta over a three-week span. Outcomes from infection with remain uncertain. We evaluated whether clinical outcomes and viral loads differed between during period when both variants were co-circulating.

Language: Английский

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A Systematic Review of Coronavirus Disease 2019 Vaccine Efficacy and Effectiveness Against Severe Acute Respiratory Syndrome Coronavirus 2 Infection and Disease

Open Forum Infectious Diseases, Journal Year: 2022, Volume and Issue: 9(6)

Published: April 18, 2022

Billions of doses coronavirus disease 2019 (COVID-19) vaccines have been administered globally, dramatically reducing severe acute respiratory syndrome 2 (SARS-CoV-2) incidence and severity in some settings. Many studies suggest provide a high degree protection against infection disease, but precise estimates vary differ design, outcomes measured, dosing regime, location, circulating virus strains. In this study, we conduct systematic review COVID-19 through February 2022. We included efficacy data from Phase 3 clinical trials for 15 undergoing World Health Organization Emergency Use Listing evaluation real-world effectiveness 8 with observational meeting inclusion criteria. Vaccine metrics collected include asymptomatic infection, any symptomatic COVID-19, including hospitalization death, partial or complete vaccination, variants concern Alpha, Beta, Gamma, Delta, Omicron. additionally the epidemiological principles behind design interpretation vaccine studies, important sources heterogeneity.

Language: Английский

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Infectious viral load in unvaccinated and vaccinated patients infected with SARS-CoV-2 WT, Delta and Omicron

medRxiv (Cold Spring Harbor Laboratory), Journal Year: 2022, Volume and Issue: unknown

Published: Jan. 11, 2022

Abstract Background Viral load (VL) is one determinant of secondary transmission SARS-CoV-2. Emergence variants concerns (VOC) Alpha and Delta was ascribed, at least partly, to higher VL. Furthermore, with parts the population vaccinated, knowledge on VL in vaccine-breakthrough infections crucial. As RNA only a weak proxy for infectiousness, studies infectious virus presence by cell culture isolation are importance. Methods We assessed nasopharyngeal swabs COVID-19 patients quantitative viral titres (IVT) focus-forming assay compared overall success genome copies. IVTs during first 5 symptomatic days total 384 patients: unvaccinated individuals infected pre-VOC SARS-CoV-2 (n= 118) or 127) vaccine breakthrough 121) Omicron (n=18). Findings Correlation between copy number IVT low all groups. No correlation age sex seen. observed copies Delta, but significantly individuals. Vaccinated had lower subjects cleared faster. In addition, vaccinated infection comparable infections. Interpretation Quantitative can give detailed insights into shedding kinetics. Vaccination associated faster clearance showing that vaccination would also risk. did not show elevated suggesting other mechanisms than increase contribute high infectiousness Omicron. Funding This work supported Swiss National Science Foundation 196644, 196383, NRP (National Research Program) 78 Covid-19 Grant 198412, Fondation Ancrage Bienfaisance du Groupe Pictet Privée des Hôpitaux Universitaires de Genève.

Language: Английский

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Inflammatory responses in the placenta upon SARS-CoV-2 infection late in pregnancy

iScience, Journal Year: 2022, Volume and Issue: 25(5), P. 104223 - 104223

Published: April 11, 2022

The effect of SARS-CoV-2 infection on placental function is not well understood. Analysis placentas from women who tested positive at delivery showed genomic and subgenomic RNA in 22 out 52 placentas. Placentas two mothers with symptomatic COVID-19 whose pregnancies resulted adverse outcomes for the fetuses contained high levels viral Alpha variant RNA. was localized to trophoblasts that cover fetal chorionic villi direct contact maternal blood. intervillous spaces were infiltrated macrophages T cells. Transcriptome analysis an increased expression chemokines pathways associated inflammation. Infection cultures live spike protein-pseudotyped lentivirus syncytiotrophoblast and, rare cases, endothelial cells mediated by ACE2 Neuropilin-1. Viruses Alpha, Beta, Delta spikes infected significantly greater levels.

Language: Английский

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Rapid emergence of SARS-CoV-2 Omicron variant is associated with an infection advantage over Delta in vaccinated persons

Med, Journal Year: 2022, Volume and Issue: 3(5), P. 325 - 334.e4

Published: April 6, 2022

Language: Английский

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Differential protection against SARS-CoV-2 reinfection pre- and post-Omicron

Nature, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 5, 2025

Abstract The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has rapidly evolved over short timescales, leading to the emergence of more transmissible variants such as Alpha and Delta 1–3 . arrival Omicron variant marked a major shift, introducing numerous extra mutations in spike gene compared with earlier 1,2 These evolutionary changes have raised concerns regarding their potential impact on immune evasion, disease severity effectiveness vaccines treatments 1,3 In this epidemiological study, we identified two distinct patterns protective effect natural infection against reinfection versus pre-Omicron eras. Before Omicron, provided strong durable protection reinfection, minimal waning time. However, during era, was robust only for those recently infected, declining time diminishing within year. results demonstrate that SARS-CoV-2 is shaped by dynamic interaction between host immunity viral evolution, contrasting before after Omicron’s first wave. This shift suggests change pressures, intrinsic transmissibility driving adaptation escape becoming dominant post-Omicron, underscoring need periodic vaccine updates sustain immunity.

Language: Английский

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The emergence of new SARS-CoV-2 variant (Omicron) and increasing calls for COVID-19 vaccine boosters-The debate continues

Travel Medicine and Infectious Disease, Journal Year: 2021, Volume and Issue: 45, P. 102246 - 102246

Published: Dec. 21, 2021

Omicron Variant of concern SARS-CoV-2 Booster dose Emerging virusesThe emergence highly mutated severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variant (B.1.1.529)has ushered panic responses around the world due to its contagious and vaccine escape mutations.This has been designated as a (VOC) by World Health Organization (WHO) [1,2].Since January 2021, multiple virus variants have emerged become dominant in many countries [Table 1].The these VOCs (Alpha, Beta, Gamma, Delta) was responsible for new waves infections across entire [3].The Delta reported increased transmissibility, higher viral load [4] high rates reinfection [5].Because ability from natural immunity [6], it became globally variant.The VOC transformed notion COVID-19 endgame created fresh discussion over-vaccination effectiveness ongoing booster campaign an already COVID-19-weary world.Compared other VOCs, this variation unusually carries exceptionally number mutations (50) on spike (S) protein, major antigenic target antibodies produced or immunization.This led scientific community investigate how much could undermine existing vaccines.The knows little about Omicron's infectivity, breakthrough, antibody resistance, reliable experimental results labs will take few weeks come out.Although conclusive immunological clinical data are not yet available, early genomic show immune evasion capabilities, fast transmission ability, rate, severity [7].This triggered calls intensify vaccination programmes, including doses [8]. 1. "Omicron" escalates debate: boost

Language: Английский

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