A5062127133- SARS-CoV-2 and COVID-19 Research
- SARS-CoV-2 detection and testing
- COVID-19 Clinical Research Studies
- Laser-induced spectroscopy and plasma
- Laser-Plasma Interactions and Diagnostics
- COVID-19 epidemiological studies
- Laser-Matter Interactions and Applications
- Respiratory viral infections research
- Atomic and Molecular Physics
- vaccines and immunoinformatics approaches
- Laser Design and Applications
- Immunotherapy and Immune Responses
- Advanced Materials Characterization Techniques
- Immune responses and vaccinations
- Animal Virus Infections Studies
- Viral Infections and Outbreaks Research
- Evolution and Genetic Dynamics
- Complex Network Analysis Techniques
- Viral gastroenteritis research and epidemiology
- Vaccine Coverage and Hesitancy
Imperial College London
2021-2025
NIHR Imperial Biomedical Research Centre
2022-2025
University of Oxford
2018-2023
Imperial College Healthcare NHS Trust
2021-2022
National Centre for Infectious Diseases
2022
The unprecedented rise in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections during December 2021 was concurrent with rapid spread of the Omicron variant England and globally. We analyzed prevalence SARS-CoV-2 its dynamics from end November to mid-December among almost 100,000 participants REACT-1 study. Prevalence high growth nationally particularly London 2021, an increasing proportion due Omicron. observed large decreases swab positivity mostly vaccinated older...
Knowledge of the window SARS-CoV-2 infectiousness is crucial in developing policies to curb transmission. Mathematical modelling based on scarce empirical evidence and key assumptions has driven isolation testing policy, but real-world data are needed. We aimed characterise across full course infection a community setting.The Assessment Transmission Contagiousness COVID-19 Contacts (ATACCC) study was UK prospective, longitudinal, cohort contacts newly diagnosed, PCR-confirmed index cases....
Background Infectiousness of respiratory viral infections is quantified as plaque forming units (PFU), requiring resource-intensive culture that not routinely performed. We hypothesised RNA load (VL) decline time (e-folding time) in people might serve an alternative marker infectiousness. Aim This study’s objective was to evaluate the association VL with and PFU area under curve (AUC) transmission risk for SARS-CoV-2 influenza A virus. Methods In virus community cohorts, by reverse...
We present experiments and numerical simulations which demonstrate that fully ionized, low-density plasma channels could be formed by hydrodynamic expansion of columns produced optical field ionization. Simulations the in hydrogen an axicon lens show generation 200 mm long with axial densities order ${n}_{\mathrm{e}}(0)=1\ifmmode\times\else\texttimes\fi{}{10}^{17}\phantom{\rule{0.16em}{0ex}}{\mathrm{cm}}^{\ensuremath{-}3}$ lowest-order modes spot size...
Abstract The SARS-CoV-2 pandemic has been characterised by the regular emergence of genomic variants. With natural and vaccine-induced population immunity at high levels, evolutionary pressure favours variants better able to evade neutralising antibodies. Omicron variant (first detected in November 2021) exhibited a degree immune evasion, leading increased infection rates worldwide. However, estimates magnitude this wave have often relied on routine testing data, which are prone several...
Abstract Rapid transmission of the SARS-CoV-2 Omicron variant has led to record-breaking case incidence rates around world. Since May 2020, REal-time Assessment Community Transmission-1 (REACT-1) study tracked spread infection in England through RT-PCR self-administered throat and nose swabs from randomly-selected participants aged 5 years over. In January 2022, we found an overall weighted prevalence 4.41% (n = 102,174), three-fold higher than November December 2021; sequenced 2,374 (99.2%)...
Abstract Background Since the emergence of SARS-CoV-2, evolutionary pressure has driven large increases in transmissibility virus. However, with increasing levels immunity through vaccination and natural infection will switch towards immune escape. Genomic surveillance regions high is crucial detecting emerging variants that can more successfully navigate landscape. Methods We present phylogenetic relationships lineage dynamics within England (a country immunity), as inferred from a random...
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We demonstrate through experiments and numerical simulations that low-density, low-loss, meter-scale plasma channels can be generated by employing a conditioning laser pulse to ionize the neutral gas collar surrounding hydrodynamic optical-field-ionized (HOFI) channel. use particle-in-cell show leading edge of ionizes generate deep, low-loss channel which guides bulk itself as well any subsequently injected pulses. In proof-of-principle experiments, we conditioned HOFI (CHOFI) waveguides...
Hydrodynamic optically-field-ionized (HOFI) plasma channels up to 100 mm long are investigated. Optical guiding is demonstrated of laser pulses with a peak input intensity 6×1017 W cm−2 through on-axis densities measured interferometrically be as low ne0=(1.0±0.3)×1017 cm−3. Guiding also observed at lower axial densities, which inferred from magneto-hydrodynamic simulations approximately 7×1016 Measurements the power attenuation lengths shown in good agreement those calculated transverse...
The Omicron wave of COVID-19 in England peaked January 2022 resulting from the rapid transmission BA.1 variant. We investigate spread and dynamics SARS-CoV-2 epidemic population during February 2022, by region, age main sub-lineage.
Abstract Background Rapid transmission of the SARS-CoV-2 Omicron variant has led to highest ever recorded case incidence levels in many countries around world. Methods The REal-time Assessment Community Transmission-1 (REACT-1) study been characterising virus using RT-PCR test results from self-administered throat and nose swabs randomly-selected participants England at ages 5 years over, approximately monthly since May 2020. Round 17 data were collected between 20 January 2022 provide on...
Prevalence of SARS-CoV-2 infection with Delta variant was increasing in England late summer 2021 among children aged 5 to 17 years, and adults who had received two vaccine doses. In September 2021, a third (booster) dose offered vaccinated 50 years over, vulnerable healthcare/care-home workers, single already 16 year-olds extended 12 15 years.
We demonstrate optical guiding of high-intensity laser pulses in long, low-density hydrodynamic optical-field-ionized (HOFI) plasma channels. An axicon lens is used to generate HOFI channels with on-axis electron densities as low ${n}_{e}(0)=1.5\ifmmode\times\else\texttimes\fi{}{10}^{17}\text{ }\text{ }{\mathrm{cm}}^{\ensuremath{-}3}$ and matched spot sizes the range $20\text{ }\ensuremath{\mu}\mathrm{m}\ensuremath{\lesssim}{W}_{M}\ensuremath{\lesssim}40\text{ }\ensuremath{\mu}\mathrm{m}$....
Background: The third wave of COVID-19 in England peaked January 2022 resulting from the rapid transmission Omicron variant. However, rates hospitalisations and deaths were substantially lower than first second waves Methods: In REal-time Assessment Community Transmission-1 (REACT-1) study we obtained data a random sample 94,950 participants with valid throat nose swab results by RT-PCR during round 18 (8 February to 1 March 2022). Findings: We estimated weighted mean SARS-CoV-2 prevalence...
Abstract Background It has been nearly a year since the first vaccinations against SARS-CoV-2 were delivered in England. The third wave of COVID-19 England began May 2021 as Delta variant to outcompete and largely replace other strains. REal-time Assessment Community Transmission-1 (REACT-1) series community surveys for infection provided insights into transmission dynamics 2020. Round 15 REACT-1 study was carried out from 19 October 5 November 2021. Methods We estimated prevalence SARS-CoV2...
Abstract Since the emergence of SARS-CoV-2, evolutionary pressure has driven large increases in transmissibility virus. However, with increasing levels immunity through vaccination and natural infection will switch towards immune escape. Here we present phylogenetic relationships lineage dynamics within England (a country high immunity), as inferred from a random community sample individuals who provided self-administered throat nose swab for rt-PCR testing part REal-time Assessment...
Abstract Background The highest-ever recorded numbers of daily severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections in England has been observed during December 2021 and have coincided with a rapid rise the highly transmissible Omicron variant despite high levels vaccination population. Although additional COVID-19 measures introduced internationally to contain epidemic, there remains uncertainty about spread severity among general Methods REal-time Assessment Community...
Summary The SARS-CoV-2 pandemic has been characterised by the regular emergence of genomic variants which have led to substantial changes in epidemiology virus. With natural and vaccine-induced population immunity at high levels, evolutionary pressure favours better able evade neutralising antibodies. Omicron variant was first detected late November 2021 exhibited a degree immune evasion, leading increased infection rates many countries. However, estimates magnitude wave relied mainly on...
We propose a novel testing and containment strategy in order to contain the spread of SARS-CoV2 while permitting large parts population resume social economic activity. Our approach recognises fact that capacities are severely constrained many countries. In this setting, we show finding best way utilise limited number tests during pandemic can be formulated concisely as an allocation problem. problem formulation takes into account heterogeneity uses pooled identify isolate individuals...
We present measurements of the temporal decay rate one-dimensional (1D), linear Langmuir waves excited by an ultrashort laser pulse. with relative amplitudes approximately $6%$ were driven $1.7\phantom{\rule{0.16em}{0ex}}\mathrm{J}$, $50\phantom{\rule{0.16em}{0ex}}\mathrm{fs}$ pulses in hydrogen and deuterium plasmas density ${n}_{e0}=8.4\ifmmode\times\else\texttimes\fi{}{10}^{17}\phantom{\rule{0.16em}{0ex}}{\mathrm{cm}}^{\ensuremath{-}3}$. The wakefield lifetimes measured to be...
Abstract Hydrodynamic optical-field-ionised (HOFI) plasma channels promise a route towards high repetition-rate, metre-scale stages for future laser accelerators. These are formed by hydrodynamic expansion of column produced optical field ionisation at the focus laser, typically from an axicon lens. Since pulses used to generate initial sub-picosecond duration, chromatic effects in lens could be important. In this paper we assess these using numerical propagation code. The code is validated...