JMIRx Med, Journal Year: 2023, Volume and Issue: 4, P. e34598 - e34598
Published: Feb. 13, 2023
Emerging SARS-CoV-2 variants have been attributed to the occurrence of secondary, tertiary, quaternary, and quinary COVID-19 epidemic waves threatening vaccine efforts owing their immune invasiveness. Since importation in South Africa, with first reported case on March 5, 2020, Africa has observed 5 consecutive waves. The evolution played a major role resurgence across globe.
Language: Английский
Mathematics, Journal Year: 2023, Volume and Issue: 11(2), P. 369 - 369
Published: Jan. 10, 2023
The aim of this paper is to investigate the qualitative behavior COVID-19 pandemic under an initial vaccination program. We constructed a mathematical model based on nonlinear system delayed differential equations. time delay represents that vaccine takes provide immune protection against SARS-CoV-2. impact transmission rates, vaccination, and dynamics system. was developed for beginning implementation programs control pandemic. perform stability analysis at equilibrium points show, using methods systems, undergoes Hopf bifurcation. theoretical results reveal some conditions related values parameters basic reproduction number, approaches disease-free point, but if number larger than one, endemic SARS-CoV-2 cannot be eradicated. Numerical examples corroborate methodology. Finally, conclusions discussions about are presented.
Language: Английский
Citations
24
Journal of Medical Virology, Journal Year: 2021, Volume and Issue: 94(4), P. 1300 - 1314
Published: Nov. 23, 2021
Young age, female sex, absence of comorbidities, and prior infection or vaccination are known epidemiological barriers for contracting the new and/or increased disease severity. Demographic trends from recent coronavirus 2019 waves, which believed to be driven by newer severe acute respiratory syndrome 2 (SARS-CoV-2) variants, indicate that aforementioned being breached a larger number younger healthy individuals developing disease. The SARS-CoV-2 variants have key mutations can induce significant changes in virus-host interactions. Recent studies report that, some these mutations, singly group, enhance mechanisms, such as binding receptor-binding domain (RBD) viral spike protein with angiotensin-converting enzyme (ACE2) receptor host-cells, increase glycosylation at antigenic sites, proteolytic cleavage protein, thus leading improved host-cell entry replication virus. putative interactions imparted RBD sequence potentially reason behind breach observed barriers. Susceptibility outcomes influenced expressions ACE2 other proteases. act more efficiently, even lesser availability entry-receptor associated proteases, efficient greater resulting high loads prolonged shedding, widespread tissue-injury, inflammation transmissibility lethality. Furthermore, accumulating evidence shows multiple reduced neutralization both, natural vaccine-acquired antibodies, indicating repeated vaccine breakthrough infections may arise serious health concerns ongoing pandemic.
Language: Английский
Citations
43
Scientific Reports, Journal Year: 2022, Volume and Issue: 12(1)
Published: Feb. 17, 2022
We develop a mathematical model to estimate the effect of New Zealand's vaccine rollout on potential spread and health impacts COVID-19. The main purpose this study is provide basis for policy advice border restrictions control measures in response outbreaks that may occur during vaccination roll-out. can be used theoretical population immunity threshold, which represents point at other controls could removed only small, occasional would take place. find that, with basic reproduction number 6, approximately representing Delta variant SARS-CoV-2, under baseline effectiveness assumptions, reaching threshold require close 100% total vaccinated. Since coverage not likely achievable practice, relaxing completely risk serious impacts. However, higher is, more collective protection has against adverse outcomes from COVID-19, easier it will become outbreaks. There remains considerable uncertainty outputs, part because evolution new variants. If variants arise are transmissible or resistant, an increase needed same level protection.
Language: Английский
Citations
38
Nature Communications, Journal Year: 2022, Volume and Issue: 13(1)
Published: Aug. 22, 2022
Control and mitigation of the COVID-19 pandemic in England has relied on a combination vaccination non-pharmaceutical interventions (NPIs). Some these NPIs are extremely costly (economically socially), so it was important to relax promptly without overwhelming already burdened health services. The eventual policy Roadmap four relaxation steps throughout 2021, taking from lock-down cessation all restrictions social interaction. In series six documents generated models assessed potential risk each step. Here we show that model projections reliable estimation medium-term hospital admission trends, with data points up September 2021 generally lying within our 95% prediction intervals. greatest uncertainties modelled scenarios came vaccine efficacy estimates against novel variants, assumptions about human behaviour face changing risk.
Language: Английский
Citations
36
The Science of The Total Environment, Journal Year: 2022, Volume and Issue: 857, P. 159326 - 159326
Published: Oct. 8, 2022
Language: Английский
Citations
36
Journal of Biomedical Science, Journal Year: 2022, Volume and Issue: 29(1)
Published: July 3, 2022
Many countries in Asia and Latin America are currently facing a double burden of outbreaks due to dengue COVID-19. Here we discuss the similarities differences between two infections so that lessons learnt far from studying both will be helpful further understanding their immunopathogenesis develop therapeutic interventions.
Language: Английский
Citations
35
Current Drug Targets, Journal Year: 2022, Volume and Issue: 23(17), P. 1593 - 1602
Published: Aug. 27, 2022
Abstract: Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) is the highly patho-genic and transmissible human coronavirus that causative agent for worldwide COVID-19 pandemic. manifests predominantly as a respiratory illness with symptoms consistent viral pneumonia, but other organ systems (e.g., kidney, heart, brain) can also be-come perturbed in patients. Accumulating data suggest significant activation of hemostatic system common pathological manifestation SARS-CoV-2 infection. The clotting protein fibrinogen one most abundant plasma proteins. Following coagulation, central coagulation protease thrombin converts to fibrin monomers, which self-assemble form matrix, primary structural component blood clot. associated profound perturbation circulating fibrinogen, intra- extravascular deposition persistence, degradation. Current findings high levels fibrino-gen degradation product D-dimer are biomarkers poor prognosis COVID-19. Moreover, emerging studies vitro animal models indicate fibrin(ogen) an active play-er pathogenesis. Here, we review current literature regarding COVID-19, including possible pathogenic mechanisms treatment strategies centered on function.
Language: Английский
Citations
27
Journal of The Royal Society Interface, Journal Year: 2023, Volume and Issue: 20(199)
Published: Feb. 1, 2023
New Zealand experienced a wave of the Omicron variant SARS-CoV-2 in early 2022, which occurred against backdrop high two-dose vaccination rates, ongoing roll-out boosters and paediatric doses, negligible levels prior infection. subvariants have subsequently emerged with significant growth advantage over previously dominant BA.2. We investigated mathematical model that included waning vaccine-derived infection-derived immunity, as well impact BA.5 subvariant began spreading May 2022. The was used to provide scenarios Government differing advantage, helping inform policy response healthcare system preparedness during winter period. In all investigated, projected peak new infections smaller than first March However, results indicated hospital occupancy likely be higher primarily due shift age distribution older groups. compare subsequent epidemiological data show provided good projection cases, hospitalizations deaths wave.
Language: Английский
Citations
16
Frontiers in Immunology, Journal Year: 2023, Volume and Issue: 14
Published: July 13, 2023
Background Breakthrough infections with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants are increasingly observed in vaccinated individuals. Immune responses towards SARS-CoV-2 variants, particularly Omicron-BA.5, poorly understood. We investigated the humoral and cellular immune of hospitalized COVID-19 patients during Delta Omicron infection waves. Methods The corresponding variant respective were identified by whole genome sequencing. Humoral analyzed ELISA a cell culture-based neutralization assay against D614G isolate (wildtype), Alpha, (AY.43) (BA.1 BA.5). Cellular immunity was evaluated an IFN-γ ELISpot assay. Results On level, showed minor response after stimulating PBMCs mutated regions variants. Neutralizing antibody titers Omicron-BA.1 especially BA.5 strongly reduced. Double-vaccinated breakthrough significantly increased neutralizing compared to double-vaccinated uninfected controls (median complete titer (NT 100 ) 640 versus 80, p<0.05). BA.1 NT 160 20 controls, p=0.07) that received booster vaccination 50 p=0.68). For boosted infection, we found no enhancing effect on Conclusion reduced infections. but not Omicron-BA.5 vaccination. Despite those may still be vulnerable for reinfections or other newly emerging concern.
Language: Английский
Citations
15
Trends in Microbiology, Journal Year: 2023, Volume and Issue: 31(12), P. 1262 - 1275
Published: Aug. 10, 2023
Language: Английский
Citations
15