Refine Search

New Search

Results: 8

(searched for: doi:10.1093/cid/ciab616)
Save to Scifeed
Page of 1
Articles per Page
by
Show export options
  Select all
Ziwei Yang, Yang Han, Shilei Ding, Andrés Finzi, Walther Mothes,
Published: 12 October 2021
Abstract:
SARS-CoV-2 variants of concern harbor mutations in the Spike (S) glycoprotein that confer more efficient transmission and dampen the efficacy of COVID-19 vaccines and antibody therapies. S mediates virus entry and is the primary target for antibody responses. Structural studies of soluble S variants have revealed an increased propensity towards conformations accessible to receptor human Angiotensin-Converting Enzyme 2 (hACE2). However, real-time observations of conformational dynamics that govern the structural equilibriums of the S variants have been lacking. Here, we report single-molecule Förster Resonance Energy Transfer (smFRET) studies of S variants containing critical mutations, including D614G and E484K, in the context of virus particles. Investigated variants predominantly occupied more open hACE2-accessible conformations, agreeing with previous structures of soluble trimers. Additionally, these S variants exhibited decelerated transitions in hACE2-accessible/bound states. Our finding of increased S kinetic stability in the open conformation provides a new perspective on SARS-CoV-2 adaptation to the human population.
, Le Gao, Qingxin Zhou, ,
Published: 26 September 2021
Abstract:
Background It was urgent and necessary to synthesize the evidence for vaccine effectiveness (VE) against SARS-CoV-2 variants of concern (VOC). We conducted a systematic review and meta-analysis to provide a comprehensive overview of the effectiveness profile of COVID-19 vaccines against VOC. Methods Published and preprinted randomized controlled trials (RCTs), cohort studies, and case-control studies that evaluated the VE against VOC (Alpha, Beta, Gamma, or Delta) were searched until 31 August 2021. Pooled estimates and 95% confidence intervals (CIs) were calculated using random-effects meta-analysis. VE was defined as (1− estimate). Results Seven RCTs (51,169 participants), 10 cohort studies (14,385,909 participants) and 16 case-control studies (734,607 cases) were included. Eight COVID-19 vaccines (mRNA-1273, BNT162b2, ChAdOx1, Ad26.COV2.S, NVX-CoV2373, BBV152, CoronaVac, and BBIBP-CorV) were included in this analysis. Full vaccination was effective against Alpha, Beta/Gamma, and Delta variants, with VE of 88.3% (95% CI, 82.4–92.2), 70.7% (95% CI, 59.9–78.5), and 71.6% (95% CI, 64.1–77.4), respectively. But partial vaccination was less effective, with VE of 59.0% (95% CI, 51.3–65.5), 49.3% (95% CI, 33.0–61.6), and 52.6% (95% CI, 43.3–60.4), respectively. mRNA vaccines seemed to have higher VE against VOC over others, significant interactions (pinteraction < 0.10) were observed between VE and vaccine type (mRNA vaccines vs. non-mRNA vaccines). Conclusions Full vaccination of COVID-19 vaccines is highly effective against Alpha variant, and moderate effective against Beta/Gamma and Delta variants. Partial vaccination has less VE against VOC. mRNA vaccines seem to have higher VE against Alpha, Beta/Gamma, and Delta variants over others.
Chang-Jie Cheng, Chun-Yi Lu, Ya-Hui Chang, Yu Sun, Hai-Jui Chu, Chun-Yu Lee, Chang-Hsiu Liu, Cheng-Huai Lin, Chien-Jung Lu,
Published: 28 August 2021
Abstract:
Objective Large clinical trials have proved the efficacy of Covid-19 vaccine, and the number of literature about the effectiveness is rapidly growing in the first half of year after mass vaccination was administrated globally. This rapid review aims to provide evidence syntheses as a means to complement the current evidence on the vaccine effectiveness (VE) against various outcomes in real-world settings. Methods This review is conducted based on the updated guideline of PRISMA 2020. Databases (PubMed, EMBASE, and MedRxiv) were searched up to 30 June 2021, (PROSPERO ID: 266866). The studies that assessed the VE of the 6 WHO-authorized vaccines (BNT162b2, ChAdOx1, Ad26.COV2.S, mRNA-1273, BBIBP-CorV, and CoronaVac) were eligible to be included. Quality assessment was performed based on ROBINS-I by 2 independent reviewers. Findings A total of 39 studies were included, covering over 15 million of participants from 11 nations. Among the general population after 2 doses of vaccination, the VE against symptomatic SARS-CoV-2 infection was estimated at 89%–97%, 92% (95% CI, 78%–97%) and 94% (95% CI, 86%–97%) for BNT162b2, ChAdOx1 and mRNA-1273, respectively. As for the protective effects against B.1.617.2 related symptomatic infection, the VE was 88% (95% CI, 85.3%–90.1%) by BNT162b2 and 67.0% (95% CI, 61.3%–71.8%) by ChAdOx1 after fully vaccination. Conclusion This review revealed a consistently high effectiveness of vaccines among the general population in real-world settings. Further studies are needed to provide the information on different races/ethnicity, the effects against SARS-CoV-2 variants, and the duration of protection with longer study time.
Otavio T Ranzani, Matt D T Hitchings, Murilo Dorion, Tatiana Lang D’Agostini, Regiane Cardoso de Paula, Olivia Ferreira Pereira de Paula, Edlaine Faria De Moura Villela, Mario Sergio Scaramuzzini Torres, Silvano Barbosa de Oliveira, Wade Schulz, et al.
Published: 20 August 2021
by BMJ
The BMJ, Volume 374; https://doi.org/10.1136/bmj.n2015

Abstract:
Objective To estimate the effectiveness of the inactivated whole virus vaccine, CoronaVac (Sinovac Biotech), against symptomatic covid-19 in the elderly population of São Paulo state, Brazil during widespread circulation of the gamma variant. Design Test negative case-control study. Setting Community testing for covid-19 in São Paulo state, Brazil. Participants 43 774 adults aged ≥70 years who were residents of São Paulo state and underwent reverse transcription polymerase chain reaction (RT-PCR) testing for SARS-CoV-2 from 17 January to 29 April 2021. 26 433 cases with symptomatic covid-19 and 17 622 test negative controls with covid-19 symptoms were formed into 13 283 matched sets, one case with to up to five controls, according to age, sex, self-reported race, municipality of residence, previous covid-19 status, and date of RT-PCR test (±3 days). Intervention Vaccination with a two dose regimen of CoronaVac. Main outcome measures RT-PCR confirmed symptomatic covid-19 and associated hospital admissions and deaths. Results Adjusted vaccine effectiveness against symptomatic covid-19 was 24.7% (95% confidence interval 14.7% to 33.4%) at 0-13 days and 46.8% (38.7% to 53.8%) at ≥14 days after the second dose. Adjusted vaccine effectiveness against hospital admissions was 55.5% (46.5% to 62.9%) and against deaths was 61.2% (48.9% to 70.5%) at ≥14 days after the second dose. Vaccine effectiveness ≥14 days after the second dose was highest for the youngest age group (70-74 years)—59.0% (43.7% to 70.2%) against symptomatic disease, 77.6% (62.5% to 86.7%) against hospital admissions, and 83.9% (59.2% to 93.7%) against deaths—and declined with increasing age. Conclusions Vaccination with CoronaVac was associated with a reduction in symptomatic covid-19, hospital admissions, and deaths in adults aged ≥70 years in a setting with extensive transmission of the gamma variant. Vaccine protection was, however, low until completion of the two dose regimen, and vaccine effectiveness was observe to decline with increasing age among this elderly population.
Wenwei Li, Yaozong Chen, Jérémie Prévost, Irfan Ullah, Maolin Lu, Shang Yu Gong, Alexandra Tauzin, Romain Gasser, Dani Vézina, Sai Priya Anand, et al.
Published: 3 August 2021
Abstract:
Summary Emerging variants of concern for the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can transmit more efficiently and partially evade protective immune responses, thus necessitating continued refinement of antibody therapies and immunogen design. Here we elucidate the structural basis and mode of action for two potent SARS-CoV-2 Spike (S) neutralizing monoclonal antibodies CV3-1 and CV3-25 that remained effective against emerging variants of concern in vitro and in vivo. CV3-1 bound to the (485-GFN-487) loop within the receptor-binding domain (RBD) in the “RBD-up” position and triggered potent shedding of the S1 subunit. In contrast, CV3-25 inhibited membrane fusion by binding to an epitope in the stem helix region of the S2 subunit that is highly conserved among β-coronaviruses. Thus, vaccine immunogen designs that incorporate the conserved regions in RBD and stem helix region are candidates to elicit pan-coronavirus protective immune responses.
Sara Carazo, Denis Talbot, Nicole Boulianne, Marc Brisson, Rodica Gilca, Geneviève Deceuninck, Nicholas Brousseau, Mélanie Drolet, Manale Ouakki, Chantal Sauvageau, et al.
Published: 22 July 2021
Abstract:
Introduction In Canada, first and second doses of mRNA vaccines against SARS-CoV-2 were uniquely spaced 16 weeks apart, but the duration of single-dose protection remains uncertain. We estimated one- and two-dose mRNA vaccine effectiveness (VE) among healthcare workers (HCWs) in Quebec, Canada including protection against varying outcome severity, variants of concern (VOC), and the stability of single-dose protection out to 16 weeks post-vaccination. Methods A test-negative design compared vaccination among SARS-CoV-2 test-positive and weekly-matched (10:1), randomly-sampled, test-negative HCWs using linked surveillance and immunization databases. Vaccine status was defined by one dose ≥14 days or two doses ≥7 days before illness onset or specimen collection. Adjusted VE was estimated by conditional logistic regression. Results Primary analysis included 5,316 cases and 53,160 controls. Single-dose VE was 70% (95%CI: 68-73) against SARS-CoV-2 infection, 73% (95%CI: 71-75) against COVID-19 illness and 97% (95%CI: 92-99) against associated hospitalization. Two-dose VE was 86% (95%CI: 81-90) and 93% (95%CI: 89-95), respectively, with no associated hospitalizations. VE was higher for non-VOC than VOC (73% Alpha) among single-dose (77%, 95%CI: 73-81 versus 63%, 95%CI: 57-67) but not two-dose recipients (87%, 95%CI: 57-96 versus 94%, 95%CI: 89-96). Across 16 weeks, no decline in single-dose VE was observed with appropriate stratification based upon prioritized vaccination determined by higher versus lower likelihood of direct patient contact. Conclusion One mRNA vaccine dose provided substantial and sustained protection to HCWs extending at least four months post-vaccination. In circumstances of vaccine shortage, delaying the second dose may be a pertinent public health strategy to consider.
Matt D.T. Hitchings, Otavio T. Ranzani, Murilo Dorion, Tatiana Lang D’Agostini, Regiane Cardoso de Paula, Olivia Ferreira Pereira de Paula, Edlaine Faria De Moura Villela, Mario Sergio Scaramuzzini Torres, Silvano Barbosa de Oliveira, Wade Schulz, et al.
Published: 22 July 2021
Abstract:
Background A two-dose regimen of ChAdOx1 coronavirus disease 19 (Covid-19) vaccine with an inter-dose interval of three months has been implemented in many countries with restricted vaccine supply. However, there is limited evidence for the effectiveness of ChAdOx1 by dose in elderly populations in countries with high prevalence of the Gamma variant of severe acute respiratory syndrome 2 (SARS-CoV-2). Methods We conducted a test-negative case-control study to estimate the effectiveness of ChAdOx1 vaccine in adults aged 60 years or older during a Gamma-variant-associated epidemic in São Paulo state, Brazil, between 17 January and 2 July 2021. Cases and matched test-negative controls were individuals, identified from surveillance databases, who experienced an acute respiratory illness and underwent SARS-CoV-2 RT-PCR testing. We used conditional logistic regression to estimate the effectiveness by dose against RT-PCR-confirmed Covid-19, Covid-19 hospitalization, and Covid-19-related death. Results 61,164 individuals were selected into matched case-control pairs. Starting ≥28 days after the first dose, adjusted effectiveness of a single dose of ChAdOx1 was 33.4% (95% CI, 26.4 to 39.7) against Covid-19, 55.1% (95% CI, 46.6 to 62.2) against hospitalization, and 61.8% (95% CI, 48.9 to 71.4) against death. Starting ≥14 days after the second dose, the adjusted effectiveness of the two-dose schedule was 77.9% (95% CI, 69.2 to 84.2) against Covid-19, 87.6% (95% CI, 78.2 to 92.9) against hospitalization, and 93.6% (95% CI, 81.9 to 97.7) against death. Conclusions Completion of the ChAdOx1 vaccine schedule afforded significantly increased protection over a single dose against mild and severe Covid-19 outcomes in elderly individuals during widespread Gamma variant transmission.
, Hannah Chung, Siyi He, Kevin A. Brown, Jonathan B. Gubbay, Sarah A. Buchan, Deshayne B. Fell, Peter C. Austin, Kevin L. Schwartz, Maria E. Sundaram, et al.
Published: 3 July 2021
Abstract:
SARS-CoV-2 variants of concern (VOC) are more transmissible and have the potential for increased disease severity and decreased vaccine effectiveness. We estimated the effectiveness of BNT162b2 (Pfizer-BioNTech Comirnaty), mRNA-1273 (Moderna Spikevax), and ChAdOx1 (AstraZeneca Vaxzevria) vaccines against symptomatic SARS-CoV-2 infection and COVID-19 hospitalization or death caused by the Alpha (B.1.1.7), Beta (B.1.351), Gamma (P.1), and Delta (B.1.617.2) VOCs in Ontario, Canada using a test-negative design study. Effectiveness against symptomatic infection ≥7 days after two doses was 89–92% against Alpha, 87% against Beta, 88% against Gamma, 82–89% against Beta/Gamma, and 87–95% against Delta across vaccine products. The corresponding estimates ≥14 days after one dose were lower. Effectiveness estimates against hospitalization or death were similar to, or higher than, against symptomatic infection. Effectiveness against symptomatic infection is generally lower for older adults (≥60 years) compared to younger adults (<60 years) for most of the VOC-vaccine combinations.
Page of 1
Articles per Page
by
Show export options
  Select all
Back to Top Top