Imperial College London

ProfessorWendyBarclay

Faculty of MedicineDepartment of Infectious Disease

Action Medical Research Chair Virology. Head of Department
 
 
 
//

Contact

 

+44 (0)20 7594 5035w.barclay

 
 
//

Location

 

416Medical SchoolSt Mary's Campus

//

Summary

 

Publications

Publication Type
Year
to

248 results found

Frise R, Baillon L, Zhou J, Kugathasan R, Peacock TP, Brown JC, Samnuan K, McKay PF, Shattock RJ, Barclay WSet al., 2022, A self-amplifying RNA vaccine protects against SARS-CoV-2 (D614G) and Alpha variant of concern (B.1.1.7) in a transmission-challenge hamster model., Vaccine, Vol: 40, Pages: 2848-2855

Vaccines for SARS-CoV-2 have been hugely successful in alleviating hospitalization and deaths caused by the newly emerged coronavirus that is the cause of COVID. However, although the parentally administered vaccines are very effective at reducing severe disease, they do not induce sterilizing immunity. As the virus continues to circulate around the globe, it is still not clear how long protection will last, nor whether variants will emerge that escape vaccine immunity. Animal models can be useful to complement studies of antigenicity of novel variants and inform decision making about the need for vaccine updates. The Syrian golden hamster is the preferred small animal model for SARS-CoV-2 infection. Since virus is efficiently transmitted between hamsters, we developed a transmission challenge model that presents a more natural dose and route of infection than the intranasal challenge usually employed. Our studies demonstrate that an saRNA vaccine based on the earliest Wuhan-like virus spike sequence induced neutralizing antibodies in sera of immunized hamsters at similar titres to those in human convalescent sera or vaccine recipients. The saRNA vaccine was equally effective at abrogating clinical signs in animals who acquired through exposure to cagemates infected either with a virus isolated in summer 2020 or with a representative Alpha (B.1.1.7) variant isolated in December 2020. The vaccine also reduced shedding of infectious virus from the nose, further reinforcing its likely effectiveness at reducing onwards transmission. This model can be extended to test the effectiveness of vaccination in blocking infections with and transmission of novel variants as they emerge.

Journal article

Elliott P, Eales O, Steyn N, Tang D, Bodinier B, Wang H, Elliott J, Whitaker M, Atchison C, Diggle P, Trotter A, Ashby D, Barclay W, Taylor G, Ward H, Darzi A, Cooke G, Donnelly C, Chadeau-Hyam Met al., 2022, Twin peaks: the Omicron SARS-CoV-2 BA.1 and BA.2 epidemics in England

BACKGROUNDRapid transmission of the SARS-CoV-2 Omicron variant has led to record-breaking incidencerates around the world. Sub-lineages have been detected in many countries with BA.1replacing Delta and BA.2 replacing BA.1.METHODSThe REal-time Assessment of Community Transmission-1 (REACT-1) study has trackedSARS-CoV-2 infection in England using RT-PCR results from self-administered throat and noseswabs from randomly-selected participants aged 5+ years. Rounds of data collection wereapproximately monthly from May 2020 to March 2022.RESULTSIn March 2022, weighted prevalence was 6.37% (N=109,181), more than twice that inFebruary 2022 following an initial Omicron peak in January 2022. Of the lineagesdetermined by viral genome sequencing, 3,382 (99.97%) were Omicron, including 346(10.2%) BA.1, 3035 (89.7%) BA.2 and one (0.03%) BA.3 sub-lineage; the remainder (1, 0.03%)was Delta AY.4. The BA.2 Omicron sub-lineage had a growth rate advantage (compared toBA.1 and sub-lineages) of 0.11 (95% credible interval [CrI], 0.10, 0.11). Prevalence wasincreasing overall (reproduction number R=1.07, 95% CrI, 1.06, 1.09), with the greatestincrease in those aged 55+ years (R=1.12, 95% CrI, 1.09, 1.14) among whom estimatedprevalence on March 31, 2022 was 8.31%, nearly 20-fold the median prevalence since May1, 2020.CONCLUSIONSWe observed unprecedented levels of SARS-CoV-2 infection in England in March 2022 and analmost complete replacement of Omicron BA.1 by BA.2. The high and increasing prevalencein older adults may increase hospitalizations and deaths despite high levels of vaccination.(Funded by the Department of Health and Social Care in England.)

Working paper

Närhi F, Moonesinghe SR, Shenkin SD, Drake TM, Mulholland RH, Donegan C, Dunning J, Fairfield CJ, Girvan M, Hardwick HE, Ho A, Leeming G, Nguyen-Van-Tam JS, Pius R, Russell CD, Shaw CA, Spencer RG, Turtle L, Openshaw PJM, Baillie JK, Harrison EM, Semple MG, Docherty AB, ISARIC4C investigatorset al., 2022, Implementation of corticosteroids in treatment of COVID-19 in the ISARIC WHO Clinical Characterisation Protocol UK: prospective, cohort study., The Lancet Digital Health, Vol: 4, Pages: e220-e234, ISSN: 2589-7500

BACKGROUND: Dexamethasone was the first intervention proven to reduce mortality in patients with COVID-19 being treated in hospital. We aimed to evaluate the adoption of corticosteroids in the treatment of COVID-19 in the UK after the RECOVERY trial publication on June 16, 2020, and to identify discrepancies in care. METHODS: We did an audit of clinical implementation of corticosteroids in a prospective, observational, cohort study in 237 UK acute care hospitals between March 16, 2020, and April 14, 2021, restricted to patients aged 18 years or older with proven or high likelihood of COVID-19, who received supplementary oxygen. The primary outcome was administration of dexamethasone, prednisolone, hydrocortisone, or methylprednisolone. This study is registered with ISRCTN, ISRCTN66726260. FINDINGS: Between June 17, 2020, and April 14, 2021, 47 795 (75·2%) of 63 525 of patients on supplementary oxygen received corticosteroids, higher among patients requiring critical care than in those who received ward care (11 185 [86·6%] of 12 909 vs 36 415 [72·4%] of 50 278). Patients 50 years or older were significantly less likely to receive corticosteroids than those younger than 50 years (adjusted odds ratio 0·79 [95% CI 0·70-0·89], p=0·0001, for 70-79 years; 0·52 [0·46-0·58], p<0·0001, for >80 years), independent of patient demographics and illness severity. 84 (54·2%) of 155 pregnant women received corticosteroids. Rates of corticosteroid administration increased from 27·5% in the week before June 16, 2020, to 75-80% in January, 2021. INTERPRETATION: Implementation of corticosteroids into clinical practice in the UK for patients with COVID-19 has been successful, but not universal. Patients older than 70 years, independent of illness severity, chronic neurological disease, and dementia, were less likely to receive corticosteroids than those who were younger, as were pregnant wom

Journal article

Chadeau-Hyam M, Wang H, Eales O, Haw D, Bodinier B, Whitaker M, Walters CE, Ainslie KEC, Atchison C, Fronterre C, Diggle PJ, Page AJ, Trotter AJ, Ashby D, Barclay W, Taylor G, Cooke G, Ward H, Darzi A, Riley S, Donnelly CA, Elliott Pet al., 2022, SARS-CoV-2 infection and vaccine effectiveness in England (REACT-1): a series of cross-sectional random community surveys, The Lancet Respiratory Medicine, Vol: 10, Pages: 355-366, ISSN: 2213-2600

SummaryBackground England has experienced a third wave of the COVID-19 epidemic since the end of May, 2021, coincidingwith the rapid spread of the delta (B.1.617.2) variant, despite high levels of vaccination among adults. Vaccinationrates (single dose) in England are lower among children aged 16–17 years and 12–15 years, whose vaccination inEngland commenced in August and September, 2021, respectively. We aimed to analyse the underlying dynamicsdriving patterns in SARS-CoV-2 prevalence during September, 2021, in England.Methods The REal-time Assessment of Community Transmission-1 (REACT-1) study, which commenced datacollection in May, 2020, involves a series of random cross-sectional surveys in the general population of Englandaged 5 years and older. Using RT-PCR swab positivity data from 100 527 participants with valid throat and noseswabs in round 14 of REACT-1 (Sept 9–27, 2021), we estimated community-based prevalence of SARS-CoV-2 andvaccine effectiveness against infection by combining round 14 data with data from round 13 (June 24 to July 12, 2021;n=172 862).Findings During September, 2021, we estimated a mean RT-PCR positivity rate of 0·83% (95% CrI 0·76–0·89), with areproduction number (R) overall of 1·03 (95% CrI 0·94–1·14). Among the 475 (62·2%) of 764 sequenced positiveswabs, all were of the delta variant; 22 (4·63%; 95% CI 3·07–6·91) included the Tyr145His mutation in the spikeprotein associated with the AY.4 sublineage, and there was one Glu484Lys mutation. Age, region, key worker status,and household size jointly contributed to the risk of swab positivity. The highest weighted prevalence was observedamong children aged 5–12 years, at 2·32% (95% CrI 1·96–2·73) and those aged 13–17 years, at 2·55% (2·11–3·08).The SARS-CoV-2 epidemic grew in those aged 5–11 years, with an R of 1&m

Journal article

Killingley B, Mann AJ, Kalinova M, Boyers A, Goonawardane N, Zhou J, Lindsell K, Hare SS, Brown J, Frise R, Smith E, Hopkins C, Noulin N, Londt B, Wilkinson T, Harden S, McShane H, Baillet M, Gilbert A, Jacobs M, Charman C, Mande P, Nguyen-Van-Tam JS, Semple MG, Read RC, Ferguson NM, Openshaw PJ, Rapeport G, Barclay WS, Catchpole AP, Chiu Cet al., 2022, Safety, tolerability and viral kinetics during SARS-CoV-2 human challenge in young adults, Nature Medicine, Pages: 1-27, ISSN: 1078-8956

Since its emergence in 2019, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused hundreds of millions of cases and continues to circulate globally. To establish a novel SARS-CoV-2 human challenge model that enables controlled investigation of pathogenesis, correlates of protection and efficacy testing of forthcoming interventions, 36 volunteers aged 18–29 years without evidence of previous infection or vaccination were inoculated with 10 TCID50 of a wild-type virus (SARS-CoV-2/human/GBR/484861/2020) intranasally in an open-label, non-randomized study (ClinicalTrials.gov identifier NCT04865237; funder, UK Vaccine Taskforce). After inoculation, participants were housed in a high-containment quarantine unit, with 24-hour close medical monitoring and full access to higher-level clinical care. The study’s primary objective was to identify an inoculum dose that induced well-tolerated infection in more than 50% of participants, with secondary objectives to assess virus and symptom kinetics during infection. All pre-specified primary and secondary objectives were met. Two participants were excluded from the per-protocol analysis owing to seroconversion between screening and inoculation, identified post hoc. Eighteen (~53%) participants became infected, with viral load (VL) rising steeply and peaking at ~5 days after inoculation. Virus was first detected in the throat but rose to significantly higher levels in the nose, peaking at ~8.87 log10 copies per milliliter (median, 95% confidence interval (8.41, 9.53)). Viable virus was recoverable from the nose up to ~10 days after inoculation, on average. There were no serious adverse events. Mild-to-moderate symptoms were reported by 16 (89%) infected participants, beginning 2–4 days after inoculation, whereas two (11%) participants remained asymptomatic (no reportable symptoms). Anosmia or dysosmia developed more slowly in 15 (83%) participants. No quantitative cor

Journal article

Pinto AL, Rai RK, Brown JC, Griffin P, Edgar JR, Shah A, Singanayagam A, Hogg C, Barclay WS, Futter CE, Burgoyne Tet al., 2022, Ultrastructural insight into SARS-CoV-2 entry and budding in human airway epithelium, NATURE COMMUNICATIONS, Vol: 13

Journal article

Chadeau-Hyam M, Tang D, Eales O, Bodinier B, Wang H, Jonnerby J, Whitaker M, Elliott J, Haw D, Walters C, Atchison C, Diggle P, Page A, Ashby D, Barclay W, Taylor G, Cooke G, Ward H, Darzi A, Donnelly C, Elliott Pet al., 2022, The Omicron SARS-CoV-2 epidemic in England during February 2022

Background The third wave of COVID-19 in England peaked in January 2022 resulting fromthe rapid transmission of the Omicron variant. However, rates of hospitalisations and deathswere substantially lower than in the first and second wavesMethods In the REal-time Assessment of Community Transmission-1 (REACT-1) study weobtained data from a random sample of 94,950 participants with valid throat and nose swabresults by RT-PCR during round 18 (8 February to 1 March 2022).Findings We estimated a weighted mean SARS-CoV-2 prevalence of 2.88% (95% credibleinterval [CrI] 2.76–3.00), with a within-round reproduction number (R) overall of 0.94 (0·91–0.96). While within-round weighted prevalence fell among children (aged 5 to 17 years) andadults aged 18 to 54 years, we observed a level or increasing weighted prevalence amongthose aged 55 years and older with an R of 1.04 (1.00–1.09). Among 1,195 positive sampleswith sublineages determined, only one (0.1% [0.0–0.5]) corresponded to AY.39 Deltasublineage and the remainder were Omicron: N=390, 32.7% (30.0–35.4) were BA.1; N=473,39.6% (36.8–42.5) were BA.1.1; and N=331, 27.7% (25.2–30.4) were BA.2. We estimated anR additive advantage for BA.2 (vs BA.1 or BA.1.1) of 0.40 (0.36–0.43). The highest proportionof BA.2 among positives was found in London.Interpretation In February 2022, infection prevalence in England remained high with levelor increasing rates of infection in older people and an uptick in hospitalisations. Ongoingsurveillance of both survey and hospitalisations data is required.Funding Department of Health and Social Care, England.

Working paper

Spencer AJ, Morris S, Ulaszewska M, Powers C, Kailath R, Bissett C, Truby A, Thakur N, Newman J, Allen ER, Rudiansyah I, Liu C, Dejnirattisai W, Mongkolsapaya J, Davies H, Donnellan FR, Pulido D, Peacock TP, Barclay WS, Bright H, Ren K, Screaton G, McTamney P, Bailey D, Gilbert SC, Lambe Tet al., 2022, The ChAdOx1 vectored vaccine, AZD2816, induces strong immunogenicity against SARS-CoV-2 beta (B.1.351) and other variants of concern in preclinical studies., EBioMedicine, Vol: 77

BACKGROUND: There is an ongoing global effort to design, manufacture, and clinically assess vaccines against SARS-CoV-2. Over the course of the ongoing pandemic a number of new SARS-CoV-2 virus isolates or variants of concern (VoC) have been identified containing mutations in key proteins. METHODS: In this study we describe the generation and preclinical assessment of a ChAdOx1-vectored vaccine (AZD2816) which expresses the spike protein of the Beta VoC (B.1.351). FINDINGS: We demonstrate that AZD2816 is immunogenic after a single dose. When AZD2816 is used as a booster dose in animals primed with a vaccine encoding the original spike protein (ChAdOx1 nCoV-19/ [AZD1222]), an increase in binding and neutralising antibodies against Beta (B.1.351), Gamma (P.1) and Delta (B.1.617.2) is observed following each additional dose. In addition, a strong and polyfunctional T cell response was measured all booster regimens. INTERPRETATION: Real world data is demonstrating that one or more doses of licensed SARS-CoV-2 vaccines confer reduced protection against hospitalisation and deaths caused by divergent VoC, including Omicron. Our data support the ongoing clinical development and testing of booster vaccines to increase immunity against highly mutated VoC. FUNDING: This research was funded by AstraZeneca with supporting funds from MRC and BBSRC.

Journal article

Zhang Z, Penn R, Barclay WS, Giotis Eet al., 2022, Naïve human macrophages are refractory to SARS-CoV-2 infection and exhibit a modest inflammatory response early in infection, Viruses, Vol: 14, Pages: 1-10, ISSN: 1999-4915

Involvement of macrophages in the SARS-CoV-2-associated cytokine storm, the excessive secretion of inflammatory/anti-viral factors leading to the acute respiratory distress syndrome (ARDS) in COVID-19 patients, is unclear. In this study, we sought to characterize the interplay between the virus and primary human monocyte-derived macrophages (MDM). MDM were stimulated with recombinant IFN- and/or infected with either live or UV-inactivated SARS-CoV- 2 or with two reassortant influenza viruses containing external genes from the H1N1 PR8 strain and heterologous internal genes from a highly pathogenic avian H5N1 or a low pathogenic human seasonal H1N1 strain. Virus replication was monitored by qRT-PCR for the E viral gene for SARS- CoV-2 or M gene for influenza and TCID50 or plaque assay, and cytokine levels were assessed semiquantitatively with qRT-PCR and a proteome cytokine array. We report that MDM are not susceptible to SARS-CoV-2 whereas both influenza viruses replicated in MDM, albeit abortively. We observed a modest cytokine response in SARS-CoV-2 exposed MDM with notable absence of IFN-β induction, which was instead strongly induced by the influenza viruses. Pre-treatment of MDM with IFN-α enhanced proinflammatory cytokine expression upon exposure to virus. Together, the findings concur that the hyperinflammation observed in SARS-CoV-2 infection is not driven by macrophages.

Journal article

Ward H, Whittaker M, Flower B, Tang S, Atchison C, Darzi A, Donnelly C, Cann A, Diggle P, Ashby D, Riley S, Barclay W, Elliott P, Cooke Get al., 2022, Population antibody responses following COVID-19 vaccination in 212,102 individuals, Nature Communications, Vol: 13, ISSN: 2041-1723

Population antibody surveillance helps track immune responses to COVID-19 vaccinations at scale, and identify host factors that may affect antibody production. We analyse data from 212,102 vaccinated individuals within the REACT-2 programme in England, which uses self-administered lateral flow antibody tests in sequential cross-sectional community samples; 71,923 (33.9%) received at least one dose of BNT162b2 vaccine and 139,067 (65.6%) received ChAdOx1. For both vaccines, antibody positivity peaks 4-5 weeks after first dose and then declines. At least 21 days after second dose of BNT162b2, close to 100% of respondents test positive, while for ChAdOx1, this is significantly reduced, particularly in the oldest age groups (72.7% [70.9–74.4] at ages 75 years and above). For both vaccines, antibody positivity decreases with age, and is higher in females and those with previous infection. Antibody positivity is lower in transplant recipients, obese individuals, smokers and those with specific comorbidities. These groups will benefit from additional vaccine doses.

Journal article

Zhou J, Peacock TP, Brown JC, Goldhill DH, Elrefaey AME, Penrice-Randal R, Cowton VM, De Lorenzo G, Furnon W, Harvey WT, Kugathasan R, Frise R, Baillon L, Lassauniere R, Thakur N, Gallo G, Goldswain H, Donovan-Banfield I, Dong X, Randle NP, Sweeney F, Glynn MC, Quantrill JL, McKay PF, Patel AH, Palmarini M, Hiscox JA, Bailey D, Barclay WSet al., 2022, Mutations that adapt SARS-CoV-2 to mink or ferret do not increase fitness in the human airway, CELL REPORTS, Vol: 38, ISSN: 2211-1247

Journal article

Elliott P, Bodinier B, Eales O, Wang H, Haw D, Elliott J, Whitaker M, Jonnerby J, Tang D, Walters CE, Atchison C, Diggle PJ, Page AJ, Trotter AJ, Ashby D, Barclay W, Taylor G, Ward H, Darzi A, Cooke GS, Chadeau-Hyam M, Donnelly CAet al., 2022, Rapid increase in Omicron infections in England during December 2021: REACT-1 study., Science, Vol: 375, Pages: eabn8347-eabn8347, ISSN: 0036-8075

The unprecedented rise in SARS-CoV-2 infections during December 2021 was concurrent with rapid spread of the Omicron variant in England and globally. We analyzed prevalence of SARS-CoV-2 and its dynamics in England from end November to mid-December 2021 among almost 100,000 participants from the REACT-1 study. Prevalence was high with rapid growth nationally and particularly in London during December 2021, and an increasing proportion of infections due to Omicron. We observed large falls in swab positivity among mostly vaccinated older children (12-17 years) compared with unvaccinated younger children (5-11 years), and in adults who received a third (booster) vaccine dose vs. two doses. Our results reinforce the importance of vaccination and booster campaigns, although additional measures have been needed to control the rapid growth of the Omicron variant.

Journal article

Eales O, Ainslie KEC, Walters CE, Wang H, Atchison C, Ashby D, Donnelly CA, Cooke G, Barclay W, Ward H, Darzi A, Elliott P, Riley Set al., 2022, Appropriately smoothing prevalence data to inform estimates of growth rate and reproduction number

<jats:title>Abstract</jats:title><jats:p>The time-varying reproduction number (<jats:bold><jats:italic>R</jats:italic></jats:bold><jats:sub><jats:bold><jats:italic>t</jats:italic></jats:bold></jats:sub>) can change rapidly over the course of a pandemic due to changing restrictions, behaviours, and levels of population immunity. Many methods exist that allow the estimation of <jats:bold><jats:italic>R</jats:italic></jats:bold><jats:sub><jats:bold><jats:italic>t</jats:italic></jats:bold></jats:sub> from case data. However, these are not easily adapted to point prevalence data nor can they infer <jats:bold><jats:italic>R</jats:italic></jats:bold><jats:sub><jats:bold><jats:italic>t</jats:italic></jats:bold></jats:sub> across periods of missing data. We developed a Bayesian P-spline model suitable for fitting to a wide range of epidemic time-series, including point-prevalence data. We demonstrate the utility of the model by fitting to periodic daily SARS-CoV-2 swab-positivity data in England from the first 7 rounds (May 2020 – December 2020) of the REal-time Assessment of Community Transmission-1 (REACT-1) study. Estimates of <jats:bold><jats:italic>R</jats:italic></jats:bold><jats:sub><jats:bold><jats:italic>t</jats:italic></jats:bold></jats:sub> over the period of two subsequent rounds (6-8 weeks) and single rounds (2-3 weeks) inferred using the Bayesian P-spline model were broadly consistent with estimates from a simple exponential model, with overlapping credible intervals. However, there were sometimes substantial differences in point estimates. The Bayesian P-spline model was further able to infer changes in <jats:bold><jats:italic>R</jats:italic></jats:bold><jats:sub><jats

Journal article

Zhang Z, Penn R, Barclay WS, Giotis ESet al., 2022, Primary macrophages exhibit a modest inflammatory response early in SARS-CoV-2 infection

<jats:title>Abstract</jats:title><jats:p>Involvement of macrophages in the SARS-CoV-2-associated cytokine storm, the excessive secretion of inflammatory/anti-viral factors leading to the acute respiratory distress syndrome (ARDS) in COVID-19 patients, is unclear. In this study, we sought to characterize the interplay between the virus and primary human monocyte-derived macrophages (MDM). MDM were stimulated with recombinant IFN-α and/or infected with either live or UV-inactivated SARS-CoV-2 or with two reassortant influenza viruses containing external genes from the H1N1 PR8 strain and heterologous internal genes from a highly pathogenic avian H5N1 or a low pathogenic human seasonal H1N1 strain. Virus replication was monitored by qRT-PCR for the <jats:italic>E</jats:italic> viral gene for SARS-CoV-2 or <jats:italic>M</jats:italic> gene for influenza and TCID<jats:sub>50</jats:sub> or plaque assay, and cytokine levels were assessed semiquantitatively with qRT-PCR and a proteome cytokine array. We report that MDM are not susceptible to SARS-CoV-2 whereas both influenza viruses replicated in MDM, albeit abortively. We observed a modest cytokine response in SARS-CoV-2 infected MDM with notable absence of IFN-β induction, which was instead strongly induced by the influenza viruses. Pre-treatment of MDM with IFN-α enhanced proinflammatory cytokine expression upon infection. Together, the findings concur that the hyperinflammation observed in SARS-CoV-2 infection is not driven by macrophages.</jats:p>

Journal article

Dejnirattisai W, Huo J, Zhou D, Zahradník J, Supasa P, Liu C, Duyvesteyn HME, Ginn HM, Mentzer AJ, Tuekprakhon A, Nutalai R, Wang B, Dijokaite A, Khan S, Avinoam O, Bahar M, Skelly D, Adele S, Johnson SA, Amini A, Ritter TG, Mason C, Dold C, Pan D, Assadi S, Bellass A, Omo-Dare N, Koeckerling D, Flaxman A, Jenkin D, Aley PK, Voysey M, Costa Clemens SA, Naveca FG, Nascimento V, Nascimento F, Fernandes da Costa C, Resende PC, Pauvolid-Correa A, Siqueira MM, Baillie V, Serafin N, Kwatra G, Da Silva K, Madhi SA, Nunes MC, Malik T, Openshaw PJM, Baillie JK, Semple MG, Townsend AR, Huang K-YA, Tan TK, Carroll MW, Klenerman P, Barnes E, Dunachie SJ, Constantinides B, Webster H, Crook D, Pollard AJ, Lambe T, OPTIC Consortium, ISARIC4C Consortium, Paterson NG, Williams MA, Hall DR, Fry EE, Mongkolsapaya J, Ren J, Schreiber G, Stuart DI, Screaton GRet al., 2022, SARS-CoV-2 Omicron-B.1.1.529 leads to widespread escape from neutralizing antibody responses, Cell, Vol: 185, Pages: 467-484.e15, ISSN: 0092-8674

On 24th November 2021, the sequence of a new SARS-CoV-2 viral isolate Omicron-B.1.1.529 was announced, containing far more mutations in Spike (S) than previously reported variants. Neutralization titers of Omicron by sera from vaccinees and convalescent subjects infected with early pandemic Alpha, Beta, Gamma, or Delta are substantially reduced, or the sera failed to neutralize. Titers against Omicron are boosted by third vaccine doses and are high in both vaccinated individuals and those infected by Delta. Mutations in Omicron knock out or substantially reduce neutralization by most of the large panel of potent monoclonal antibodies and antibodies under commercial development. Omicron S has structural changes from earlier viruses and uses mutations that confer tight binding to ACE2 to unleash evolution driven by immune escape. This leads to a large number of mutations in the ACE2 binding site and rebalances receptor affinity to that of earlier pandemic viruses.

Journal article

Gray-Rodriguez S, Jensen MP, Otero-Jimenez M, Hanley B, Swann OC, Ward PA, Salguero FJ, Querido N, Farkas I, Velentza-Almpani E, Weir J, Barclay WS, Carroll MW, Jaunmuktane Z, Brandner S, Pohl U, Allinson K, Thom M, Troakes C, Al-Sarraj S, Sastre M, Gveric D, Gentleman S, Roufosse C, Osborn M, Alegre-Abarrategui Jet al., 2022, Multisystem screening reveals SARS-CoV-2 in neurons of the myenteric plexus and in megakaryocytes, Journal of Pathology, ISSN: 0022-3417

SARS-CoV-2, the causative agent of COVID-19, typically manifests as a respiratory illness although extrapulmonary involvement, such as in the gastrointestinal tract and nervous system, as well as frequent thrombotic events, are increasingly recognised. How this maps onto SARS-CoV-2 organ tropism at the histological level, however, remains unclear. Here, we perform a comprehensive validation of a monoclonal antibody against the SARS-CoV-2 nucleocapsid protein (NP) followed by systematic multisystem organ immunohistochemistry analysis of the viral cellular tropism in tissue from 36 patients, 16 post-mortem cases and 16 biopsies with polymerase chain reaction (PCR)-confirmed SARS-CoV-2 status from the peaks of the pandemic in 2020 and four pre-COVID post-mortem controls. SARS-CoV-2 anti-NP staining in the post-mortem cases revealed broad multiorgan involvement of the respiratory, digestive, haematopoietic, genitourinary and nervous systems, with a typical pattern of staining characterised by punctate paranuclear and apical cytoplasmic labelling. The average time from symptom onset to time of death was shorter in positively versus negatively stained post-mortem cases (mean = 10.3 days versus mean = 20.3 days, p = 0.0416, with no cases showing definitive staining if the interval exceeded 15 days). One striking finding was the widespread presence of SARS-CoV-2 NP in neurons of the myenteric plexus, a site of high ACE-2 expression, the entry receptor for SARS-CoV-2, and one of the earliest affected cells in Parkinson's disease. In the bone marrow, we observed viral SARS-CoV-2 NP within megakaryocytes, key cells in platelet production and thrombus formation. In 15 tracheal biopsies performed in patients requiring ventilation, there was a near complete concordance between immunohistochemistry and PCR swab results. Going forward, our findings have relevance to correlating clinical symptoms to the organ tropism of

Journal article

Pollock KM, Cheeseman HM, Szubert AJ, Libri V, Boffito M, Owen D, Bern H, O'Hara J, McFarlane LR, Lemm N-M, McKay PF, Rampling T, Yim YTN, Milinkovic A, Kingsley C, Cole T, Fagerbrink S, Aban M, Tanaka M, Mehdipour S, Robbins A, Budd W, Faust SN, Hassanin H, Cosgrove CA, Winston A, Fidler S, Dunn DT, McCormack S, Shattock RJ, COVAC1 study Groupet al., 2022, Safety and immunogenicity of a self-amplifying RNA vaccine against COVID-19: COVAC1, a phase I, dose-ranging trial, EClinicalMedicine, Vol: 44, ISSN: 2589-5370

Background: Lipid nanoparticle (LNP) encapsulated self-amplifying RNA (saRNA) is a novel technology formulated as a low dose vaccine against COVID-19. Methods: A phase I first-in-human dose-ranging trial of a saRNA COVID-19 vaccine candidate LNP-nCoVsaRNA, was conducted at Imperial Clinical Research Facility, and participating centres in London, UK, between 19th June to 28th October 2020. Participants received two intramuscular (IM) injections of LNP-nCoVsaRNA at six different dose levels, 0.1-10.0μg, given four weeks apart. An open-label dose escalation was followed by a dose evaluation. Solicited adverse events (AEs) were collected for one week from enrolment, with follow-up at regular intervals (1-8 weeks). The binding and neutralisation capacity of anti-SARS-CoV-2 antibody raised in participant sera was measured by means of an anti-Spike (S) IgG ELISA, immunoblot, SARS-CoV-2 pseudoneutralisation and wild type neutralisation assays. (The trial is registered: ISRCTN17072692, EudraCT 2020-001646-20). Findings: 192 healthy individuals with no history or serological evidence of COVID-19, aged 18-45 years were enrolled. The vaccine was well tolerated with no serious adverse events related to vaccination. Seroconversion at week six whether measured by ELISA or immunoblot was related to dose (both p<0.001), ranging from 8% (3/39; 0.1μg) to 61% (14/23; 10.0μg) in ELISA and 46% (18/39; 0.3μg) to 87% (20/23; 5.0μg and 10.0μg) in a post-hoc immunoblot assay. Geometric mean (GM) anti-S IgG concentrations ranged from 74 (95% CI, 45-119) at 0.1μg to 1023 (468-2236) ng/mL at 5.0μg (p<0.001) and was not higher at 10.0μg. Neutralisation of SARS-CoV-2 by participant sera was measurable in 15% (6/39; 0.1μg) to 48% (11/23; 5.0μg) depending on dose level received. Interpretation: Encapsulated saRNA is safe for clinical development, is immunogenic at low dose levels but failed to induce 100% seroconversion. Modifications to optimis

Journal article

Singanayagam A, Hakki S, Dunning J, Madon KJ, Crone MA, Koycheva A, Derqui-Fernandez N, Barnett JL, Whitfield MG, Varro R, Charlett A, Kundu R, Fenn J, Cutajar J, Quinn V, Conibear E, Barclay W, Freemont PS, Taylor GP, Ahmad S, Zambon M, Ferguson NM, Lalvani A, ATACCC Study Investigatorset al., 2022, Community transmission and viral load kinetics of the SARS-CoV-2 delta (B.1.617.2) variant in vaccinated and unvaccinated individuals in the UK: a prospective, longitudinal, cohort study., The Lancet. Infectious diseases, Vol: 22, Pages: 183-195, ISSN: 1473-3099

<h4>Background</h4>The SARS-CoV-2 delta (B.1.617.2) variant is highly transmissible and spreading globally, including in populations with high vaccination rates. We aimed to investigate transmission and viral load kinetics in vaccinated and unvaccinated individuals with mild delta variant infection in the community.<h4>Methods</h4>Between Sept 13, 2020, and Sept 15, 2021, 602 community contacts (identified via the UK contract-tracing system) of 471 UK COVID-19 index cases were recruited to the Assessment of Transmission and Contagiousness of COVID-19 in Contacts cohort study and contributed 8145 upper respiratory tract samples from daily sampling for up to 20 days. Household and non-household exposed contacts aged 5 years or older were eligible for recruitment if they could provide informed consent and agree to self-swabbing of the upper respiratory tract. We analysed transmission risk by vaccination status for 231 contacts exposed to 162 epidemiologically linked delta variant-infected index cases. We compared viral load trajectories from fully vaccinated individuals with delta infection (n=29) with unvaccinated individuals with delta (n=16), alpha (B.1.1.7; n=39), and pre-alpha (n=49) infections. Primary outcomes for the epidemiological analysis were to assess the secondary attack rate (SAR) in household contacts stratified by contact vaccination status and the index cases' vaccination status. Primary outcomes for the viral load kinetics analysis were to detect differences in the peak viral load, viral growth rate, and viral decline rate between participants according to SARS-CoV-2 variant and vaccination status.<h4>Findings</h4>The SAR in household contacts exposed to the delta variant was 25% (95% CI 18-33) for fully vaccinated individuals compared with 38% (24-53) in unvaccinated individuals. The median time between second vaccine dose and study recruitment in fully vaccinated contacts was longer for infected individuals (medi

Journal article

Singanayagam A, Hakki S, Dunning J, Madon KJ, Crone MA, Koycheva A, Derqui-Fernandez N, Barnett JL, Whitfield MG, Varro R, Charlett A, Kundu R, Fenn J, Cutajar J, Quinn V, Conibear E, Barclay W, Freemont PS, Taylor GP, Ahmad S, Zambon M, Ferguson NM, Lalvani A, Badhan A, Dustan S, Tejpal C, Ketkar AV, Narean JS, Hammett S, McDermott E, Pillay T, Houston H, Luca C, Samuel J, Bremang S, Evetts S, Poh J, Anderson C, Jackson D, Miah S, Ellis J, Lackenby Aet al., 2022, Community transmission and viral load kinetics of the SARS-CoV-2 delta (B.1.617.2) variant in vaccinated and unvaccinated individuals in the UK: a prospective, longitudinal, cohort study, The Lancet Infectious Diseases, Vol: 22, Pages: 183-195, ISSN: 1473-3099

BackgroundThe SARS-CoV-2 delta (B.1.617.2) variant is highly transmissible and spreading globally, including in populations with high vaccination rates. We aimed to investigate transmission and viral load kinetics in vaccinated and unvaccinated individuals with mild delta variant infection in the community.MethodsBetween Sept 13, 2020, and Sept 15, 2021, 602 community contacts (identified via the UK contract-tracing system) of 471 UK COVID-19 index cases were recruited to the Assessment of Transmission and Contagiousness of COVID-19 in Contacts cohort study and contributed 8145 upper respiratory tract samples from daily sampling for up to 20 days. Household and non-household exposed contacts aged 5 years or older were eligible for recruitment if they could provide informed consent and agree to self-swabbing of the upper respiratory tract. We analysed transmission risk by vaccination status for 231 contacts exposed to 162 epidemiologically linked delta variant-infected index cases. We compared viral load trajectories from fully vaccinated individuals with delta infection (n=29) with unvaccinated individuals with delta (n=16), alpha (B.1.1.7; n=39), and pre-alpha (n=49) infections. Primary outcomes for the epidemiological analysis were to assess the secondary attack rate (SAR) in household contacts stratified by contact vaccination status and the index cases’ vaccination status. Primary outcomes for the viral load kinetics analysis were to detect differences in the peak viral load, viral growth rate, and viral decline rate between participants according to SARS-CoV-2 variant and vaccination status.FindingsThe SAR in household contacts exposed to the delta variant was 25% (95% CI 18–33) for fully vaccinated individuals compared with 38% (24–53) in unvaccinated individuals. The median time between second vaccine dose and study recruitment in fully vaccinated contacts was longer for infected individuals (median 101 days [IQR 74–120]) than for unin

Journal article

Elliott P, Eales O, Bodinier B, Tang D, Wang H, Jonnerby J, Haw D, Elliott J, Whitaker M, Walters C, Atchison C, Diggle P, Page A, Trotter A, Ashby D, Barclay W, Taylor G, Ward H, Darzi A, Cooke G, Chadeau-Hyam M, Donnelly Cet al., 2022, Post-peak dynamics of a national Omicron SARS-CoV-2 epidemic during January 2022

Background: Rapid transmission of the SARS-CoV-2 Omicron variant has led to the highestever recorded case incidence levels in many countries around the world.Methods: The REal-time Assessment of Community Transmission-1 (REACT-1) study hasbeen characterising the transmission of the SARS-CoV-2 virus using RT-PCR test results fromself-administered throat and nose swabs from randomly-selected participants in England atages 5 years and over, approximately monthly since May 2020. Round 17 data were collectedbetween 5 and 20 January 2022 and provide data on the temporal, socio-demographic andgeographical spread of the virus, viral loads and viral genome sequence data for positiveswabs.Results: From 102,174 valid tests in round 17, weighted prevalence of swab positivity was4.41% (95% credible interval [CrI], 4.25% to 4.56%), which is over three-fold higher than inDecember 2021 in England. Of 3,028 sequenced positive swabs, 2,393 lineages weredetermined and 2,374 (99.2%) were Omicron including 19 (0.80% of all Omicron lineages)cases of BA.2 sub-lineage and one BA.3 (0.04% of all Omicron) detected on 17 January 2022,and only 19 (0.79%) were Delta. The growth of the BA.2 Omicron sub-lineage against BA.1and its sub-lineage BA.1.1 indicated a daily growth rate advantage of 0.14 (95% CrI, 0.03,0.28) for BA.2, which corresponds to an additive R advantage of 0.46 (95% CrI, 0.10, 0.92).Within round 17, prevalence was decreasing overall (R=0.95, 95% CrI, 0.93, 0.97) butincreasing in children aged 5 to 17 years (R=1.13, 95% CrI, 1.09, 1.18). Those 75 years andolder had a swab-positivity prevalence of 2.46% (95% CI, 2.16%, 2.80%) reflecting a highlevel of infection among a highly vulnerable group. Among the 3,613 swab-positiveindividuals reporting whether or not they had had previous infection, 2,334 (64.6%)reported previous confirmed COVID-19. Of these, 64.4% reported a positive test from 1 to30 days before their swab date. Risks of infection were increased among essential/keyworkers

Working paper

Keeling MJ, Dyson L, Guyver-Fletcher G, Holmes A, Semple MG, Tildesley MJ, Hill EMet al., 2022, Fitting to the UK COVID-19 outbreak, short-term forecasts and estimating the reproductive number, Statistical Methods in Medical Research, ISSN: 0962-2802

The COVID-19 pandemic has brought to the fore the need for policy makers to receive timely and ongoing scientific guidance in response to this recently emerged human infectious disease. Fitting mathematical models of infectious disease transmission to the available epidemiological data provide a key statistical tool for understanding the many quantities of interest that are not explicit in the underlying epidemiological data streams. Of these, the effective reproduction number, R, has taken on special significance in terms of the general understanding of whether the epidemic is under control (R<1). Unfortunately, none of the epidemiological data streams are designed for modelling, hence assimilating information from multiple (often changing) sources of data is a major challenge that is particularly stark in novel disease outbreaks. Here, focusing on the dynamics of the first wave (March–June 2020), we present in some detail the inference scheme employed for calibrating the Warwick COVID-19 model to the available public health data streams, which span hospitalisations, critical care occupancy, mortality and serological testing. We then perform computational simulations, making use of the acquired parameter posterior distributions, to assess how the accuracy of short-term predictions varied over the time course of the outbreak. To conclude, we compare how refinements to data streams and model structure impact estimates of epidemiological measures, including the estimated growth rate and daily incidence.

Journal article

Peacock TP, Brown JC, Zhou J, Thakur N, Newman J, Kugathasan R, Sukhova K, Kaforou M, Bailey D, Barclay WSet al., 2022, The SARS-CoV-2 variant, Omicron, shows rapid replication in human primary nasal epithelial cultures and efficiently uses the endosomal route of entry

<jats:title>Abstract</jats:title><jats:p>At the end of 2021 a new SARS-CoV-2 variant, Omicron, emerged and quickly spread across the world. It has been demonstrated that Omicron’s high number of Spike mutations lead to partial immune evasion from even polyclonal antibody responses, allowing frequent re-infection and vaccine breakthroughs. However, it seems unlikely these antigenic differences alone explain its rapid growth; here we show Omicron replicates rapidly in human primary airway cultures, more so even than the previously dominant variant of concern, Delta. Omicron Spike continues to use human ACE2 as its primary receptor, to which it binds more strongly than other variants. Omicron Spike mediates enhanced entry into cells expressing several different animal ACE2s, including various domestic avian species, horseshoe bats and mice suggesting it has an increased propensity for reverse zoonosis and is more likely than previous variants to establish an animal reservoir of SARS-CoV-2. Unlike other SARS-CoV-2 variants, however, Omicron Spike has a diminished ability to induce syncytia formation. Furthermore, Omicron is capable of efficiently entering cells in a TMPRSS2-independent manner, via the endosomal route. We posit this enables Omicron to infect a greater number of cells in the respiratory epithelium, allowing it to be more infectious at lower exposure doses, and resulting in enhanced intrinsic transmissibility.</jats:p>

Journal article

David A, Parkinson N, Peacock TP, Pairo-Castineira E, Khanna T, Cobat A, Tenesa A, Sancho-Shimizu V, Casanova J-L, Abel L, Barclay WS, Baillie JK, Sternberg MJEet al., 2022, A common TMPRSS2 variant has a protective effect against severe COVID-19, Current Research in Translational Medicine, Vol: 70, ISSN: 2452-3186

Background: The human protein transmembrane protease serine type 2 (TMPRSS2) plays a key role in SARS-CoV-2 infection, as it is required to activate the virus’ spike protein, facilitating entry into target cells. We hypothesized that naturally-occurring TMPRSS2 human genetic variants affecting the structure and function of the TMPRSS2 protein may modulate the severity of SARS-CoV-2 infection.Methods: We focused on the only common TMPRSS2 non-synonymous variant predicted to be damaging (rs12329760 C>T, p.V160M), which has a minor allele frequency ranging from from 0.14 in Ashkenazi Jewish to 0.38 in East Asians. We analysed the association between the rs12329760 and COVID-19 severity in 2,244 critically ill patients with COVID-19 from 208 UK intensive care units recruited as part of the GenOMICC (Genetics Of Mortality In Critical Care) study. Logistic regression analyses were adjusted for sex, age and deprivation index. For in vitro studies, HEK293 cells were co-transfected with ACE2 and either TMPRSS2 wild type or mutant (TMPRSS2V160M). A SARS-CoV-2 pseudovirus entry assay was used to investigate the ability of TMPRSS2V160M to promote viral entry.Results: We show that the T allele of rs12329760 is associated with a reduced likelihood of developing severe COVID-19 (OR 0.87, 95%CI:0.79-0.97, p=0.01). This association was stronger in homozygous individuals when compared to the general population (OR 0.65, 95%CI:0.50-0.84, p=1.3 × 10−3). We demonstrate in vitro that this variant, which causes the amino acid substitution valine to methionine, affects the catalytic activity of TMPRSS2 and is less able to support SARS-CoV-2 spike-mediated entry into cells.Conclusion: TMPRSS2 rs12329760 is a common variant associated with a significantly decreased risk of severe COVID-19. Further studies are needed to assess the expression of TMPRSS2 across different age groups. Moreover, our results identify TMPRSS2 as a promising drug target, with a potential role for

Journal article

Elliott P, Bodinier B, Eales O, Wang H, Haw D, Elliott J, Whitaker M, Jonnerby J, Tang D, Walters C, Atchison C, Diggle P, Page A, Trotter A, Ashby D, Barclay W, Taylor G, Ward H, Darzi A, Cooke G, Chadeau-Hyam M, Donnelly Cet al., 2021, Rapid increase in Omicron infections in England during December 2021: REACT-1 study

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 in the highly transmissible Omicron variant despite high levels of vaccination in the population. Although additional COVID-19 measures have beenintroduced in England and internationally to contain the epidemic, there remains uncertainty about the spread and severity of Omicron infections among the general population.Methods: The REal-time Assessment of Community Transmission–1 (REACT-1) study has been monitoring the prevalence of SARS-CoV-2 infection in England since May 2020.REACT-1 obtains self-administered throat and nose swabs from a random sample of the population of England at ages 5 years and over. Swabs are tested for SARS-CoV-2 infection by reverse transcription polymerase chain reaction (RT-PCR) and samples testing positive are sent for viral genome sequencing. To date 16 rounds have been completed, each including~100,000 or more participants with data collected over a period of 2 to 3 weeks per month.Socio-demographic, lifestyle and clinical information (including previous history of COVID-19 and symptoms prior to swabbing) is collected by online or telephone questionnaire. Here we report results from round 14 (9-27 September 2021), round 15 (19 October - 05 November2021) and round 16 (23 November - 14 December 2021) for a total of 297,728 participants with a valid RT-PCR test result, of whom 259,225 (87.1%) consented for linkage to their NHS records including detailed information on vaccination (vaccination status, date). We usedthese data to estimate community prevalence and trends by age and region, to evaluate vaccine effectiveness against infection in children ages 12 to 17 years, and effect of a third (booster) dose in adults, and to monitor the emergence of the Omicron variant in England.Results: We observed a high overall prevalen

Working paper

Dowell AC, Butler MS, Jinks E, Tut G, Lancaster T, Sylla P, Begum J, Bruton R, Pearce H, Verma K, Logan N, Tyson G, Spalkova E, Margielewska-Davies S, Taylor GS, Syrimi E, Baawuah F, Beckmann J, Okike I, Ahmad S, Garstang J, Brent AJ, Brent B, Ireland G, Aiano F, Amin-Chowdhury Z, Jones S, Borrow R, Linley E, Wright J, Azad R, Waiblinger D, Davis C, Thomson E, Palmarini M, Willett BJ, Barclay WS, Poh J, Amirthalingam G, Brown KE, Ramsay ME, Zuo J, Moss P, Ladhani Set al., 2021, Children develop robust and sustained cross-reactive spike-specific immune responses to SARS-CoV-2 infection, NATURE IMMUNOLOGY, Vol: 23, Pages: 40-+, ISSN: 1529-2908

Journal article

McCrone JT, Hill V, Bajaj S, Pena RE, Lambert BC, Inward R, Bhatt S, Volz E, Ruis C, Dellicour S, Baele G, Zarebski AE, Sadilek A, Wu N, Schneider A, Ji X, Raghwani J, Jackson B, Colquhoun R, O'Toole Á, Peacock TP, Twohig K, Thelwall S, Dabrera G, Myers R, COVID-19 genomics UK COG-UK consortium, Faria NR, Huber C, Bogoch II, Khan K, du Plessis L, Barrett JC, Aanensen DM, Barclay WS, Chand M, Connor T, Loman NJ, Suchard MA, Pybus OG, Rambaut A, Kraemer MUGet al., 2021, Context-specific emergence and growth of the SARS-CoV-2 Delta variant., medRxiv

The Delta variant of concern of SARS-CoV-2 has spread globally causing large outbreaks and resurgences of COVID-19 cases 1-3 . The emergence of Delta in the UK occurred on the background of a heterogeneous landscape of immunity and relaxation of non-pharmaceutical interventions 4,5 . Here we analyse 52,992 Delta genomes from England in combination with 93,649 global genomes to reconstruct the emergence of Delta, and quantify its introduction to and regional dissemination across England, in the context of changing travel and social restrictions. Through analysis of human movement, contact tracing, and virus genomic data, we find that the focus of geographic expansion of Delta shifted from India to a more global pattern in early May 2021. In England, Delta lineages were introduced >1,000 times and spread nationally as non-pharmaceutical interventions were relaxed. We find that hotel quarantine for travellers from India reduced onward transmission from importations; however the transmission chains that later dominated the Delta wave in England had been already seeded before restrictions were introduced. In England, increasing inter-regional travel drove Delta's nationwide dissemination, with some cities receiving >2,000 observable lineage introductions from other regions. Subsequently, increased levels of local population mixing, not the number of importations, was associated with faster relative growth of Delta. Among US states, we find that regions that previously experienced large waves also had faster Delta growth rates, and a model including interactions between immunity and human behaviour could accurately predict the rise of Delta there. Delta's invasion dynamics depended on fine scale spatial heterogeneity in immunity and contact patterns and our findings will inform optimal spatial interventions to reduce transmission of current and future VOCs such as Omicron.

Journal article

Kraemer M, McCrone J, Hill V, Bajaj S, Evans-Pena R, Lambert B, Inward R, Bhatt S, Volz E, Ruis C, Dellicour S, Baele G, Zarebski A, Sadilek A, Wu N, Schneider A, Ji X, Raghwani J, Jackson B, Colquhoun R, O'Toole A, Peacock T, Twohig K, Thelwall S, Dabrera G, Meyers R, Faria N, Huber C, Khan K, Bogoch I, Plessis L, Barrett J, Aanensen D, Barclay W, Chand M, Connor T, Loman N, Suchard M, Pybus O, Rambaut Aet al., 2021, Context-specific emergence and growth of the SARS-CoV-2 Delta variant., Res Sq

The Delta variant of concern of SARS-CoV-2 has spread globally causing large outbreaks and resurgences of COVID-19 cases. The emergence of Delta in the UK occurred on the background of a heterogeneous landscape of immunity and relaxation of non-pharmaceutical interventions. Here we analyse 52,992 Delta genomes from England in combination with 93,649 global genomes to reconstruct the emergence of Delta, and quantify its introduction to and regional dissemination across England, in the context of changing travel and social restrictions. Through analysis of human movement, contact tracing, and virus genomic data, we find that the focus of geographic expansion of Delta shifted from India to a more global pattern in early May 2021. In England, Delta lineages were introduced >1,000 times and spread nationally as non-pharmaceutical interventions were relaxed. We find that hotel quarantine for travellers from India reduced onward transmission from importations; however the transmission chains that later dominated the Delta wave in England had been already seeded before restrictions were introduced. In England, increasing inter-regional travel drove Delta's nationwide dissemination, with some cities receiving >2,000 observable lineage introductions from other regions. Subsequently, increased levels of local population mixing, not the number of importations, was associated with faster relative growth of Delta. Among US states, we find that regions that previously experienced large waves also had faster Delta growth rates, and a model including interactions between immunity and human behaviour could accurately predict the rise of Delta there. Delta’s invasion dynamics depended on fine scale spatial heterogeneity in immunity and contact patterns and our findings will inform optimal spatial interventions to reduce transmission of current and future VOCs such as Omicron.

Journal article

Eales O, Page AJ, de Oliveira Martins L, Wang H, Bodinier B, Haw D, Jonnerby J, Atchison C, Ashby D, Barclay W, Taylor G, Cooke G, Ward H, Darzi A, Riley S, Chadeau-Hyam M, Donnelly CA, Elliott Pet al., 2021, SARS-CoV-2 lineage dynamics in England from September to November 2021: high diversity of Delta sub-lineages and increased transmissibility of AY.4.2

<jats:title>Abstract</jats:title><jats:p>Since the emergence of SARS-CoV-2, evolutionary pressure has driven large increases in the transmissibility of the virus. However, with increasing levels of immunity through vaccination and natural infection the evolutionary pressure will switch towards immune escape. Here we present phylogenetic relationships and lineage dynamics within England (a country with high levels of immunity), as inferred from a random community sample of individuals who provided a self-administered throat and nose swab for rt-PCR testing as part of the REal-time Assessment of Community Transmission-1 (REACT-1) study. From 9 to 27 September 2021 (round 14) and 19 October to 5 November 2021 (round 15), all lineages sequenced within REACT-1 were Delta or a Delta sub-lineage with 44 unique lineages identified. The proportion of the original Delta variant (B.1.617.2) was found to be increasing between September and November 2021, which may reflect an increasing number of sub-lineages which have yet to be identified. The proportion of B.1.617.2 was greatest in London, which was further identified as a region with an increased level of genetic diversity. The Delta sub-lineage AY.4.2 was found to be robustly increasing in proportion, with a reproduction number 15% (8%, 23%) greater than its parent and most prevalent lineage, AY.4. Both AY.4.2 and AY.4 were found to be geographically clustered in September but this was no longer the case by late October/early November, with only the lineage AY.6 exhibiting clustering towards the South of England. Though no difference in the viral load based on cycle threshold (Ct) values was identified, a lower proportion of those infected with AY.4.2 had symptoms for which testing is usually recommend (loss or change of sense of taste, loss or change of sense of smell, new persistent cough, fever), compared to AY.4 (p = 0.026). The evolutionary rate of SARS-CoV-2, as measured by the mutation rate, was fou

Journal article

Davis C, Logan N, Tyson G, Orton R, Harvey WT, Perkins JS, Mollett G, Blacow RM, Peacock TP, Barclay WS, Cherepanov P, Palmarini M, Murcia PR, Patel AH, Robertson DL, Haughney J, Thomson EC, Willett BJet al., 2021, Reduced neutralisation of the Delta (B.1.617.2) SARS-CoV-2 variant of concern following vaccination, PLOS PATHOGENS, Vol: 17, ISSN: 1553-7366

Journal article

Chadeau M, Wang H, Eales O, Haw D, Bodinier B, Whitaker M, Walters C, Ainslie K, Atchison C, Fronterre C, Diggle P, Page A, Trotter A, Ashby D, Barclay W, Taylor G, Cooke G, Ward H, Darzi A, Riley S, Donnelly C, Elliott Pet al., 2021, Randomised community surveys of SARS-CoV-2 infection and vaccine effectiveness in England: REACT-1 study., The Lancet Respiratory Medicine, ISSN: 2213-2600

Background: England experienced a third wave of the COVID-19 epidemic from end May 2021 coinciding with the rapid spread of Delta variant despite high levels of vaccination among adults. Vaccination rates (single-dose) are lower among children aged 16-17 and 12-15 years whose vaccination in England commenced in August and September respectively. Methods: The REACT-1 study involves a series of random cross-sectional surveys in the general population of England aged 5 years and over. Using RT-PCR swab-positivity data from (N=100,527) participants with valid swabs in round 14 (9 to 27 September 2021), we estimated community-based prevalence of SARS-CoV-2 and vaccine effectiveness against infection by combining data with round 13 (24 June to 12 July 2021, N=172,862).Findings: During September 2021 we estimated a mean RT-PCR positivity rate of 0.83% (0.76%, 0.89%) with a reproduction number R overall of 1.03 (0.94, 1.14). Among the 475 sequenced positive swabs, all were Delta variant; 22 (4.63%) included the Y145H mutation in the spike protein associated with the AY.4 sub-lineage, and there was one E484K mutation. Age, region, key worker status, and household size jointly contributed to the risk of swab-positivity. The highest weighted prevalence was observed among children aged 5-12 years at 2.32% (1.96%, 2.73%) and 13-17 years at 2.55% (2.11%, 3.08%). The epidemic grew in those aged 5-11 years with R of 1.42, but decreased in those aged 18-54. At ages 18-64 years, the adjusted vaccine effectiveness against infection was 62.8% (49.3%, 72.7%) after two doses compared to unvaccinated people, for all vaccines combined, and 44.8% (22.5%, 60.7%) and 71.3% (56.6%, 81.0%) for AstraZeneca and Pfizer-BioNTech, respectively. At ages >18 years, weighted prevalence of swab-positivity was 0.35% (0.31%, 0.40%) if second dose was <3 months before their swab but 0.55% (0.50%, 0.61%) for those who received their second dose 3-6 months prior, compared to 1.76% (1.60%, 1.95%) among

Journal article

This data is extracted from the Web of Science and reproduced under a licence from Thomson Reuters. You may not copy or re-distribute this data in whole or in part without the written consent of the Science business of Thomson Reuters.

Request URL: http://wlsprd.imperial.ac.uk:80/respub/WEB-INF/jsp/search-html.jsp Request URI: /respub/WEB-INF/jsp/search-html.jsp Query String: respub-action=search.html&id=00516862&limit=30&person=true