delta wave
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2022 ◽  
Vol 27 (1) ◽  
Author(s):  
Paolo Bosetti ◽  
Cécile Tran Kiem ◽  
Alessio Andronico ◽  
Juliette Paireau ◽  
Daniel Levy-Bruhl ◽  
...  

Europe has experienced a large COVID-19 wave caused by the Delta variant in winter 2021/22. Using mathematical models applied to Metropolitan France, we find that boosters administered to ≥ 65, ≥ 50 or ≥ 18 year-olds may reduce the hospitalisation peak by 25%, 36% and 43% respectively, with a delay of 5 months between second and third dose. A 10% reduction in transmission rates might further reduce it by 41%, indicating that even small increases in protective behaviours may be critical to mitigate the wave.


2022 ◽  
Author(s):  
Thomas J. Hladish ◽  
Alexander N. Pillai ◽  
Ira M. Longini

In this report, we use a detailed simulation model to assess and project the COVID-19 epidemic in Florida. The model is a data-driven, stochastic, discrete-time, agent based model with an explicit representation of people and places. Using the model, we find that the omicron variant wave in Florida is likely to cause many more infections than occurred during the delta variant wave. Due to testing limitations and often mild symptoms, however, we anticipate that omicron infections will be underreported compared to delta. We project that reported cases of COVID-19 will continue to grow significantly and peak in early January 2022, and that the number of reported COVID-19 deaths due to omicron may be 1/3 of the total caused by the delta wave.


2021 ◽  
Author(s):  
Anna A Mensah ◽  
Helen Campbell ◽  
Julia Stowe ◽  
Giulia Seghezzo ◽  
Ruth Simmons ◽  
...  

AbstractBackgroundReinfection after primary SARS-CoV-2 infection is uncommon in adults, but little is known about the risks, characteristics, severity or outcomes of reinfection in children.MethodsWe used national SARS-CoV-2 testing data in England to estimate the risk of reinfection ≥90 days after primary infection from 01 January 2020 to 31 July 2021, which encompassed both the Alpha and Delta waves in England. Disease severity was assessed by linking reinfection cases to national hospitalisation, intensive care admission and death registrations datasets.FindingsReinfection rates closely followed community infection rates, with a small peak during the Alpha wave and a larger peak during the Delta wave. In children aged ≤16 years, there were 688,418 primary infections and 2,343 reinfections. The overall reinfection rate was 66·88/100,000 population, being higher in adults (72.53/100,000) than in children (21·53/100,000). Reinfection rates after primary infection were 0·68% overall, 0·73% in adults and 0·34% in children. Of the 109 reinfections in children admitted to hospital, 78 (72%) had underlying comorbidities. Hospitalisation rates were similar for the first (64/2343, 2·73%) and second episode (57/2343, 2·43%). Intensive care admission was rare after primary infection (n=7) or reinfection (n=4), mainly in children with comorbidities. 44 deaths occurred after primary infection within 28 days of diagnosis (44/688,418, 0·01%), none after possible reinfections.InterpretationThe risk of SARS-CoV-2 reinfection is strongly related to exposure due to community infection rates, especially during the Delta variant wave. Children had a lower risk of reinfection than adults, but reinfections were not associated with more severe disease or fatal outcomes.FundingPHE/UKHSAResearch in ContextEvidence Before this studyWe searched PubMed with the terms “COVID-19” or “SARS-CoV-2” with “reinfection” to identify publications relating to SARS-CoV-2 reinfections from 01 January until 15 November 2021. There were few publications relating to SARS-CoV-2 reinfections, and these primarily related to adults. Published studies reported very low rates of reinfection during the first few months after primary infection in adults. COVID-19 vaccines provide effective immune protection against SARS-CoV-2 infection, but recent studies have reported increasing risk of breakthrough infection with time since primary vaccination due to waning immunity. Several SARS-CoV-2 variants, including the beta, gamma and delta variants have been shown to partially evade immunity after natural infection and vaccination, potentially increasing the risk of reinfections and breakthrough infections, respectively. Data on reinfections in children are lacking and restricted mainly to case reports in immunocompromised children.Added Value of This StudyWe used national SARS-CoV-2 testing data during the first 19 months of the pandemic to estimate the risk of reinfection in children compared to adults during a period that encompassed both the Alpha and the Delta variant waves in England. We found that the risk of reinfection correlated with the risk of SARS-CoV-2 exposure and therefore, closely reflected community infection rates, with most reinfections occurring during the Delta variant wave. Whilst acknowledging the limitation of using national testing data, we found that children had a lower risk of reinfection compared to adults and that the risk of reinfection in children increased with age. Reinfections were not associated with severe disease in terms of hospitalization or intensive care admission and there were no fatalities within 28 days of the reinfection episode in children.Implications of all the Available EvidenceSARS-CoV-2 reinfections are rare in children, especially younger children, and occurred mainly during the Delta wave in England. Reinfections were not associated with more severe disease or fatal outcomes in children. COVID-19 vaccination will provide further protection against primary infections and reinfections in children.


2021 ◽  
Author(s):  
Antonin Bal ◽  
Grégory Destras ◽  
Bruno Simon ◽  
Jean-Marc Giannoli ◽  
Florence Morfin ◽  
...  

AbstractHerein, we describe the characteristics of vaccine breakthrough infections (VBI) in fully vaccinated individuals according to five vaccine strategies during the Delta wave in France. Inclusion criterion was a positive test at least 2 weeks after a full vaccine schedule: homologous vaccination with Pfizer-BioNTech (BNT162b2) or Moderna (mRNA-1273); heterologous vaccination with Astrazeneca and Pfizer-BioNTech (ChadOx1/BNT162b2); single-dose vaccines Johnson & Johnson (Ad26.COV2.S) or Astrazeneca (ChadOx1). A total of 1630 VBI from patients fully vaccinated between February and July were included in this study. SARS-CoV-2 sequencing performed for 1366 samples showed that the delta variant represented 94.1% (1286/1366). Delta-VBI were mainly symptomatic (mild symptoms) with no difference according to the vaccine strategy (p=0.362). The median RT-PCR Ct values at diagnosis were significantly different between symptomatic and asymptomatic cases only for BNT162b2 group (17.7 (15.07, 20.51) vs 19.00 (16.00, 23.00), p=0.004). Up to 50% of VBI was classified as early-VBI (infected less than one month after full immunization) for BNT162b2, mRNA-1273, ChadOx1, and J Ad26.COV2.S. People aged 14-49 yo were overrepresented in early VBI compared to non-early VBI for BNT162b2 and mRNA-1273 (73.92% vs 37.87% for BNT162b2 and 77.78% vs 46.67 % for mRNA-1273, p<0.05). Our data emphasize a high prevalence of Delta-VBI occurring only one month after full immunization in young patients that might be related to relaxation of barrier gestures.


Author(s):  
Weizhuo Liu ◽  
Wentao Gu ◽  
Xinping Luo ◽  
Jian Li ◽  
Nanqing Xiong

A 27-year-old female presenting palpitation without ECG documentation underwent electrophysiology study. EP study revealed atrioventricular accessory pathway with poor and unidirectional pathway conduction, and a fasciculoventricular pathway. During isoproterenol infusion, delta wave promptly became prominent, after which an antidromic AV reentrant tachycardia was induced. When the pathway was mapped, widely split double pathway potentials were observed at 12 o’clock site of tricuspid annulus during mild preexcitation, demonstrating an example of intra-pathway conduction delay, which can be reversed by isoproterenol. Ablation at the site caused accelerated pathway rhythm and eliminated the pathway, rendering the tachycardia non-inducible.


2021 ◽  
Author(s):  
Marta Juanes-Gonzalez ◽  
Ana Calderon-Valdiviezo ◽  
Helena Losa-Puig ◽  
Roger Valls-Foix ◽  
Marta Gonzalez-Salvador ◽  
...  

BACKGROUND: Some authors have reported that angiotensin converter enzyme inhibitors (ACEI) and angiotensin receptor blockers (ARB) improve clinical outcomes in hypertensive COVID-19 patients, and others have proposed cross-protection for influenza vaccination. This study explores the impact of these variables on the evolution of hospitalized patients, focusing in the first wave and the Delta wave. METHODS: Hospitalizations (n=1888) from March 1, 2020, to July 31, 2021, in the Hospital of Terrassa, the referral center for the free access Terrassa Health Consortium in the North Metropolitan Barcelona Health Region (population=167,386) were studied. The number of chronic treatments and conditions of patients from the initial outbreak (n=184) and the Delta outbreak (n=158) were recorded. RESULTS: Of the non-survivors, 96.3% were aged >60 years in the first wave and 100% were aged >70 years in the Delta wave. In non-survival hospitalized patients aged >60 years, the percentage treated with ACEI was similar to general population but was significantly different for ARB treatments of influenza vaccination, although associated to a higher comorbidity and age. In July 2021, the number of hospitalizations for patients aged <50 years was higher than March 2020 and 22% of hospitalized patients without chronic treatments and conditions needed admission to the intensive care unit. Mortality was reduced in the groups with most comorbidities who received influenza and SARS-CoV2 vaccination. CONCLUSIONS: In COVID-19 infection, age and comorbidity are related to survival, ACEI use is safe. A high proportion of patients without comorbidity require hospitalization and intensive care.


Author(s):  
Clarissa Oeser ◽  
Heather Whitaker ◽  
Ezra Linley ◽  
Ray Borrow ◽  
Simon Tonge ◽  
...  
Keyword(s):  

Author(s):  
Bastien Lechat ◽  
Kristy L Hansen ◽  
Yohannes Adama Melaku ◽  
Andrew Vakulin ◽  
Gorica Micic ◽  
...  

2021 ◽  
Vol 10 (19) ◽  
pp. 4394
Author(s):  
Thomas Senoner ◽  
Bernhard Pfeifer ◽  
Fabian Barbieri ◽  
Agne Adukauskaite ◽  
Wolfgang Dichtl ◽  
...  

(1) Background: The exact anatomic localization of the accessory pathway (AP) in patients with Wolff–Parkinson–White (WPW) syndrome still relies on an invasive electrophysiologic study, which has its own inherent risks. Determining the AP localization using a 12-lead ECG circumvents this risk but is of limited diagnostic accuracy. We developed and validated an artificial intelligence-based algorithm (location of accessory pathway artificial intelligence (locAP AI)) using a neural network to identify the AP location in WPW syndrome patients based on the delta-wave polarity in the 12-lead ECG. (2) Methods: The study included 357 consecutive WPW syndrome patients who underwent successful catheter ablation at our institution. Delta-wave polarity was assessed by four independent electrophysiologists, unaware of the site of successful catheter ablation. LocAP AI was trained and internally validated in 357 patients to identify the correct AP location among 14 possible locations. The AP location was also determined using three established tree-based, ECG-based algorithms (Arruda, Milstein, and Fitzpatrick), which provide limited resolutions of 10, 5, and 8 AP locations, respectively. (3) Results: LocAP AI identified the correct AP location with an accuracy of 85.7% (95% CI 79.6–90.5, p < 0.0001). The algorithms by Arruda, Milstein, and Fitzpatrick yielded a predictive accuracy of 53.2%, 65.6%, and 44.7%, respectively. At comparable resolutions, the locAP AI achieved a predictive accuracy of 95.0%, 94.9%, and 95.6%, respectively (p < 0.001 for differences). (4) Conclusions: Our AI-based algorithm provided excellent accuracy in predicting the correct AP location. Remarkably, this accuracy is achieved at an even higher resolution of possible anatomical locations compared to established tree-based algorithms.


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