Cucinotta D, Vanelli M. WHO Declares COVID-19 a Pandemic. Acta Biomed 2020;91:157–60. https://doi.org/10.23750/abm.v91i1.9397.
World Health Organization. COVID-19 Weekly Epidemiological Update (Edition 64). 2021. https://www.who.int/publications/m/item/weekly-epidemiological-update-on-covid-19%2D%2D-2-november-2021.
WHO. SARS-CoV-2 Variants. World Health Organization 2020. http://www.who.int/csr/don/31-december-2020-sars-cov2-variants/en/. Accessed 9 Mar 2021.
WHO. COVID-19 Weekly Epidemiological Update - 25 February 2021. 2021. https://www.who.int/publications/m/item/covid-19-weekly-epidemiological-update. Accessed 9 Mar 2021.
WHO. Tracking SARS-CoV-2 variants. https://www.who.int/en/activities/tracking-SARS-CoV-2-variants/ . Accessed 7 Jun 2021.
Curran JA, Dol J, Boulos L, et al. Transmission characteristics of SARS-CoV-2 variants of concern: Rapid Scoping Review. medRxiv. 2021;2021.04.23.21255515. https://doi.org/10.1101/2021.04.23.21255515.
WHO. Weekly operational update on COVID-19 - 24 May 2021. 2021. https://www.who.int/publications/m/item/weekly-operational-update-on-covid-19%2D%2D-24-may-2021. Accessed 28 May 2021.
Innovation A for C. Living Evidence - SARS-CoV-2 variants. Agency for Clinical Innovation. 2021. https://aci.health.nsw.gov.au/covid-19/critical-intelligence-unit/sars-cov-2-variants. Accessed 24 Apr 2021.
Davies NG, Abbott S, Barnard RC, et al. Estimated transmissibility and impact of SARS-CoV-2 lineage B.1.1.7 in England. Science 2021;372. https://doi.org/10.1126/science.abg3055.
WHO. COVID-19 Weekly epidemiological update - April 13, 2021. https://www.who.int/publications/m/item/weekly-epidemiological-update-on-covid-19%2D%2D-13-april-2021. Accessed 24 Apr 2021.
Wibmer CK, Ayres F, Hermanus T, et al. SARS-CoV-2 501Y.V2 escapes neutralization by South African COVID-19 donor plasma. bioRxiv. Published Online First: 1 March 2021. https://doi.org/10.1101/2021.01.18.427166.
Mahase E. Delta variant: What is happening with transmission, hospital admissions, and restrictions? BMJ. 2021;n1513. https://doi.org/10.1136/bmj.n1513.
WHO. Pulse survey on continuity of essential health services during the COVID-19 pandemic: interim report, 27 August 2020. 2020. https://www.who.int/publications-detail-redirect/WHO-2019-nCoV-EHS_continuity-survey-2020.1. Accessed 26 Apr 2021.
Tuite A, Fisman D, Odutayo A, et al. COVID-19 Hospitalizations, ICU Admissions and Deaths Associated with the New Variants of Concern. https://doi.org/10.47326/ocsat.2021.02.18.1.0.
Somerville M, Curran JA, Dol J, et al. Public health implications of SARS-CoV-2 variants of concern: a rapid scoping review. BMJ Open. 2021;11:e055781. https://doi.org/10.1136/bmjopen-2021-055781.
Article
PubMed
Google Scholar
Tricco AC, Langlois EV, Straus SE, et al. Rapid reviews to strengthen health policy and systems: a practical guide. 2017. http://apps.who.int/iris/bitstream/10665/258698/1/9789241512763-eng.pdf. Accessed 9 Mar 2021.
Garritty C, Gartlehner G, Nussbaumer-Streit B, et al. Cochrane Rapid Reviews Methods Group offers evidence-informed guidance to conduct rapid reviews. J Clin Epidemiol. 2020; https://doi.org/10.1016/j.jclinepi.2020.10.007.
Aromataris E, Munn Z, editors. JBI Manual for Evidence Synthesis. JBI 2020. https://doi.org/10.46658/JBIMES-20-01.
Shamseer L, Moher D, Clarke M, et al. Preferred reporting items for systematic review and meta-analysis protocols (PRISMA-P) 2015: elaboration and explanation. BMJ. 2015;350:g7647. https://doi.org/10.1136/bmj.g7647.
Article
PubMed
Google Scholar
Dol J, Curran J, Bolous L, et al. COVID-19 variants of concern – a rapid scoping review protocol. Open Science Framework Published Online First: 2021. https://osf.io/7ugpf/. Accessed 25 Jun 2021.
Page MJ, McKenzie JE, Bossuyt PM, et al. The PRISMA 2020 statement: an updated guideline for reporting systematic reviews. BMJ. 2021;372:n71. https://doi.org/10.1136/bmj.n71.
Article
PubMed
PubMed Central
Google Scholar
Canadian Agency for Drugs and Technologies in Health (CADTH). CADTH COVID-19 Search Strings - COVID-19 - Medline. 2021. https://covid.cadth.ca/literature-searching-tools/cadth-covid-19-search-strings/#covid-19-medline.
McGowan J, Sampson M, Salzwedel DM, et al. PRESS peer review of electronic search strategies: 2015 guideline statement. J Clin Epidemiol. 2016;75:40–6. https://doi.org/10.1016/j.jclinepi.2016.01.021.
Article
PubMed
Google Scholar
de Andrade CLT, Lima SML, Martins M, et al. Has the age distribution of hospitalized Covid-19 patients changed in Brazil? medRxiv. 2021;2021.03.30.21254650. https://doi.org/10.1101/2021.03.30.21254650.
de Oliveira MHS, Lippi G, Henry BM. Sudden rise in COVID-19 case fatality among young and middle-aged adults in the south of Brazil after identification of the novel B.1.1.28.1 (P.1) SARS-CoV-2 strain: analysis of data from the state of Parana. medRxiv. 2021;2021.03.24.21254046. https://doi.org/10.1101/2021.03.24.21254046.
Moore CM, Sergienko R, Arbel R. SARS-CoV-2 alpha variant: is it really more deadly? A population level observational study. MedRxiv Published Online First: 18 August 2021. https://doi.org/10.1101/2021.08.17.21262167.
Jabłońska K, Aballéa S, Auquier P, et al. On the association between SARS-COV-2 variants and COVID-19 mortality during the second wave of the pandemic in Europe. medRxiv. 2021;2021.03.25.21254289. https://doi.org/10.1101/2021.03.25.21254289.
Freitas ARR, Beckedorff OA, Cavalcanti LP de G, et al. A emergência da nova variante P.1 do SARS-CoV-2 no Amazonas (Brasil) foi temporalmente associada a uma mudança no perfil da mortalidade devido a COVID-19, segundo sexo e idade. Published Online First: 26 March 2021. https://doi.org/10.1590/SciELOPreprints.2030.
Budhiraja S, Indrayan A, Aggarwal M, et al. Differentials in the characteristics of COVID-19 cases in Wave-1 and Wave-2 admitted to a network of hospitals in North India. MedRxiv Published Online First: 27 June 2021. https://doi.org/10.1101/2021.06.24.21259438.
Freitas ARR, Lemos DRQ, Beckedorff OA, et al. The increase in the risk of severity and fatality rate of covid-19 in southern Brazil after the emergence of the Variant of Concern (VOC) SARS-CoV-2 P.1 was greater among young adults without pre-existing risk conditions. medRxiv. 2021;2021.04.13.21255281. https://doi.org/10.1101/2021.04.13.21255281.
Dabrera G, Allen H, Zaidi A, et al. Assessment of Mortality and Hospital Admissions Associated with Confirmed Infection with SARS-CoV-2 Variant of Concern VOC-202012/01 (B.1.1.7) a Matched Cohort and Time-to-Event Analysis. SSRN Electronic Journal Published Online First: 1 January 2021. https://doi.org/10.2139/ssrn.3802578.
Erman A, Mishra S, Barrett KA, et al. Variant-of-concern-attributable health and health system-related outcomes: a population-level propensity-score matched cohort study. MedRxiv Published Online First: 3 June 2021. https://doi.org/10.1101/2021.06.02.21257869.
Fisman DN, Tuite AR. Progressive Increase in Virulence of Novel SARS-CoV-2 Variants in Ontario, Canada. MedRxiv Published Online First: 7 July 2021. https://doi.org/10.1101/2021.07.05.21260050.
Martin-Blondel G, Lescure F-X, Assoumou L, et al. Increased risk of severe COVID-19 in hospitalized patients with SARS-CoV-2 variant of concern alpha infection in France: a multicentre matched cohort study with retrospective data collection. SSRN Journal Published Online First: 2021. https://doi.org/10.2139/ssrn.3866550.
McAlister FA, Nabipoor M, Chu A, et al. Lessons from the COVID-19 Third Wave in Canada: The Impact of Variants of Concern and Shifting Demographics. MedRxiv Published Online First: 28 August 2021. https://doi.org/10.1101/2021.08.27.21261857.
Puech B, Legrand A, Simon O, et al. Prognosis of Critically Ill Patients With Acute Respiratory Failure Due To The SARS-CoV-2 501Y.V2 Variant: A Multicenter Retrospective Matched Cohort Study. In Review 2021. https://doi.org/10.21203/rs.3.rs-806080/v2.
Swann OV, Pollock L, Holden KA, et al. Comparison of children and young people admitted with SARS-CoV-2 across the UK in the first and second pandemic waves: prospective multicentre observational cohort study. MedRxiv Published Online First: 17 September 2021. https://doi.org/10.1101/2021.09.14.21263567.
Vassallo M, Manni S, Klotz C, et al. Patients admitted for variant alpha COVID-19 have poorer outcomes than those infected with the old strain. JCM. 2021;10:3550. https://doi.org/10.3390/jcm10163550.
Article
CAS
PubMed
PubMed Central
Google Scholar
Zavascki AP, Vieceli T, Wink PL, et al. Advanced ventilatory support and mortality in hospitalized patients with COVID-19 caused by Gamma (P.1) variant of concern compared to other lineages: cohort study at a reference center in Brazil. In Review 2021. https://doi.org/10.21203/rs.3.rs-910467/v1.
Agrawal N, Sharma A, Kumar Sahu S, et al. Clinical and demographic features of SARS-COV-2 variants of concern (VOC): B.1.1.7 and B.1.617.2 at a tertiary care hospital in southern Rajasthan. Eur J Mol Clin Med. 2021;8:702–8.
Google Scholar
Snell LB, Wang W, Alcolea-Medina A, et al. First and second SARS-CoV-2 waves in inner London: A comparison of admission characteristics and the impact of the B.1.1.7 variant. medRxiv 2021;2021.03.16.21253377. https://doi.org/10.1101/2021.03.16.21253377.
Havers FP, Pham H, Taylor CA, et al. COVID-19-associated hospitalizations among vaccinated and unvaccinated adults ≥18 years – COVID-NET, 13 states, January 1 – July 24, 2021. MedRxiv Published Online First: 29 August 2021. https://doi.org/10.1101/2021.08.27.21262356.
Khedar RS, Mittal K, Ambaliya HC, et al. Greater Covid-19 Severity and Mortality in Hospitalized Patients in Second (Delta Variant) Wave Compared to the First: Single Centre Prospective Study in India. MedRxiv Published Online First: 7 September 2021. https://doi.org/10.1101/2021.09.03.21263091.
Maslo C, Messina A, Laubscher A, et al. COVID-19: A comparative study of severity of patients hospitalized during the first and the second wave in South Africa. MedRxiv Published Online First: 11 May 2021. https://doi.org/10.1101/2021.05.11.21257033.
Adhikari EH, SoRelle JA, McIntire DD, et al. Increasing severity of COVID-19 in pregnancy with Delta (B.1.617.2) variant surge. Am J Obstet Gynecol 2021;:S000293782101005X. https://doi.org/10.1016/j.ajog.2021.09.008.
Cetin M, Balci PO, Sivgin H, et al. Alpha variant (B.1.1.7) of SARS-CoV-2 increases fatality-rate for patients under age of 70 years and hospitalization risk overall. AMicr Published Online First: 11 August 2021. https://doi.org/10.1556/030.2021.01524.
Courjon J, Contenti J, Demonchy E, et al. COVID-19 patients age, comorbidity profiles and clinical presentation related to the SARS-CoV-2 UK-variant spread in the southeast of France. Sci Rep. 2021;11:18456. https://doi.org/10.1038/s41598-021-95067-7.
Article
CAS
PubMed
PubMed Central
Google Scholar
Loconsole D, Centrone F, Morcavallo C, et al. Rapid spread of the SARS-CoV-2 variant of concern 202012/01 in southern Italy (December 2020-March 2021). Int J Environ Res Public Health. 2021;18. https://doi.org/10.3390/ijerph18094766.
Louis G, Goetz C, Mellati N, et al. Preliminary data on severe SARS-CoV-2 infection caused by the 501Y.V2 variant. Anaesth Crit Care Pain Med 2021;40:100890. https://doi.org/10.1016/j.accpm.2021.100890.
Martínez-García L, Espinel MA, Abreu M, et al. Emergence and Spread of B.1.1.7 Lineage in Primary Care and Clinical Impact in the Morbi-Mortality among Hospitalized Patients in Madrid, Spain. Microorganisms 2021;9:1517. https://doi.org/10.3390/microorganisms9071517.
AlQahtani M, Bhattacharyya S, Alawadi A, et al. Morbidity and mortality from COVID-19 post-vaccination breakthrough infections in association with vaccines and the emergence of variants in Bahrain. In Review 2021. https://doi.org/10.21203/rs.3.rs-828021/v1.
Takemoto MLS, Nakamura-Pereira M, Menezes MO, et al. Higher case fatality rate among obstetric patients with COVID-19 in the second year of pandemic in Brazil: do new genetic variants play a role? medRxiv 2021;:2021.05.06.21256651. https://doi.org/10.1101/2021.05.06.21256651.
Bager P, Wohlfahrt J, Fonager J, et al. Risk of hospitalisation associated with infection with SARS-CoV-2 lineage B.1.1.7 in Denmark: an observational cohort study. Lancet Infect Dis. 2021;21:1507–17. https://doi.org/10.1016/S1473-3099(21)00290-5.
Article
CAS
PubMed
PubMed Central
Google Scholar
Challen R, Brooks-Pollock E, Read JM, et al. Risk of mortality in patients infected with SARS-CoV-2 variant of concern 202012/1: matched cohort study. BMJ. 2021;372:n579. https://doi.org/10.1136/bmj.n579.
Article
PubMed
Google Scholar
Cusinato M, Gates J, Jajbhay D, et al. Increased risk of death in covid-19 hospital admissions during the second wave as compared to the first epidemic wave. A prospective dynamic cohort study in South London, UK. Infection Published Online First: 12 June 2021. https://doi.org/10.1101/2021.06.09.21258537.
Dennis JM, McGovern AP, Thomas NJ, et al. Trends in 28-day mortality of critical care patients with coronavirus disease 2019 in the United Kingdom: a National Cohort Study, march 2020 to January 2021*. Crit Care Med. 2021;49:1895–900. https://doi.org/10.1097/CCM.0000000000005184.
Article
CAS
PubMed
PubMed Central
Google Scholar
Frampton D, Rampling T, Cross A, et al. Genomic characteristics and clinical effect of the emergent SARS-CoV-2 B.1.1.7 lineage in London, UK: a whole-genome sequencing and hospital-based cohort study. Lancet Infect Dis 2021. https://doi.org/10.1016/S1473-3099(21)00170-5.
Grint DJ, Wing K, Houlihan C, et al. Severity of Severe Acute Respiratory System Coronavirus 2 (SARS-CoV-2) Alpha Variant (B.1.1.7) in England. Clinical Infectious Diseases 2021;ciab754. https://doi.org/10.1093/cid/ciab754.
Haas EJ, Angulo FJ, McLaughlin JM, et al. Impact and effectiveness of mRNA BNT162b2 vaccine against SARS-CoV-2 infections and COVID-19 cases, hospitalisations, and deaths following a nationwide vaccination campaign in Israel: an observational study using national surveillance data. Lancet. 2021;397:1819–29. https://doi.org/10.1016/S0140-6736(21)00947-8.
Article
CAS
PubMed
PubMed Central
Google Scholar
Jassat W, Mudara C, Ozougwu L, et al. Difference in mortality among individuals admitted to hospital with COVID-19 during the first and second waves in South Africa: a cohort study. Lancet Glob Health. 2021;9:e1216–25. https://doi.org/10.1016/S2214-109X(21)00289-8.
Article
PubMed
PubMed Central
Google Scholar
Nyberg T, Twohig KA, Harris RJ, et al. Risk of hospital admission for patients with SARS-CoV-2 variant B.1.1.7: cohort analysis. BMJ 2021;n1412. https://doi.org/10.1136/bmj.n1412.
Area I, Lorenzo H, Marcos PJ, et al. One year of the COVID-19 pandemic in Galicia: a global view of age-group statistics during three waves. IJERPH. 2021;18:5104. https://doi.org/10.3390/ijerph18105104.
Article
PubMed
PubMed Central
Google Scholar
Funk T, Pharris A, Spiteri G, et al. Characteristics of SARS-CoV-2 variants of concern B.1.1.7, B.1.351 or P.1: data from seven EU/EEA countries, weeks 38/2020 to 10/2021. Euro Surveill. 2021;26. https://doi.org/10.2807/1560-7917.ES.2021.26.16.2100348.
Garvey MI, McMurray C, Casey AL, et al. Observations of SARS-CoV-2 variant of concern B.1.1.7 at the UK’s largest hospital Trust. J Infect Published Online First: 28 April 2021. https://doi.org/10.1016/j.jinf.2021.04.026.
Graham MS, Sudre CH, May A, et al. Changes in symptomatology, reinfection, and transmissibility associated with the SARS-CoV-2 variant B.1.1.7: an ecological study. Lancet Public Health. 2021;6:e335–45. https://doi.org/10.1016/S2468-2667(21)00055-4.
Article
PubMed
PubMed Central
Google Scholar
Ong SWX, Chiew CJ, Ang LW, et al. Clinical and Virological Features of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Variants of Concern: A Retrospective Cohort Study Comparing B.1.1.7 (Alpha), B.1.351 (Beta), and B.1.617.2 (Delta). Clinical Infectious Diseases 2021;ciab721. https://doi.org/10.1093/cid/ciab721.
Pascall DJ, Mollett G, Blacow R, et al. The SARS-CoV-2 Alpha variant causes increased clinical severity of disease. MedRxiv Published Online First: 24 August 2021. https://doi.org/10.1101/2021.08.17.21260128.
Patone M, Thomas K, Hatch R, et al. Mortality and critical care unit admission associated with the SARS-CoV-2 lineage B.1.1.7 in England: an observational cohort study. Lancet Infect Dis. 2021;21:1518–28. https://doi.org/10.1016/S1473-3099(21)00318-2.
Article
CAS
PubMed
PubMed Central
Google Scholar
Stirrup O, Boshier F, Venturini C, et al. SARS-CoV-2 lineage B.1.1.7 is associated with greater disease severity among hospitalised women but not men: multicentre cohort study. BMJ Open Resp Res. 2021;8:e001029. https://doi.org/10.1136/bmjresp-2021-001029.
Article
PubMed
Google Scholar
Twohig KA, Nyberg T, Zaidi A, et al. Hospital admission and emergency care attendance risk for SARS-CoV-2 delta (B.1.617.2) compared with alpha (B.1.1.7) variants of concern: a cohort study. Lancet Infect Dis 2021;S1473309921004758. https://doi.org/10.1016/S1473-3099(21)00475-8.
Veneti L, Seppälä E, Larsdatter Storm M, et al. Increased risk of hospitalisation and intensive care admission associated with reported cases of SARS-CoV-2 variants B.1.1.7 and B.1.351 in Norway, December 2020 –May 2021. PLoS One. 2021;16:e0258513. https://doi.org/10.1371/journal.pone.0258513.
Veneti L, Valcarcel Salamanca B, Seppälä E, et al. No difference in risk of hospitalisation between reported cases of the SARS-CoV-2 Delta variant and Alpha variant in Norway. MedRxiv Published Online First: 5 September 2021. https://doi.org/10.1101/2021.09.02.21263014.
Whittaker R, Kristofferson AB, Seppälä E, et al. Trajectories of hospitalisation for patients infected with SARS-CoV-2 variant B.1.1.7 in Norway, December 2020 – April 2021. J Infect 2021;83:e14–e17. https://doi.org/10.1016/j.jinf.2021.07.025.
Nonaka CKV, Gräf T, Barcia CA de L, et al. SARS-CoV-2 variant of concern P.1 (Gamma) infection in young and middle-aged patients admitted to the intensive care units of a single hospital in Salvador, Northeast Brazil, February 2021. Int J Infect Dis 2021;111:47–54. https://doi.org/10.1016/j.ijid.2021.08.003.
Abu-Raddad LJ, Chemaitelly H, Ayoub HH, et al. Severity, criticality, and fatality of the SARS-CoV-2 Beta variant. Clinical Infectious Diseases Published Online First: 4 August 2021. https://doi.org/10.1101/2021.08.02.21261465.
Di Domenico L, Sabbatini CE, Pullano G, et al. Impact of January 2021 curfew measures on SARS-CoV-2 B.1.1.7 circulation in France. Euro Surveill 2021;26. 10.2807/1560-7917.ES.2021.26.15.2100272.
Mitze T, Rode J. Early assessment of epidemiological trends associated with SARS-CoV-2 variants of concern in Germany. medRxiv 2021;2021.02.16.21251803. https://doi.org/10.1101/2021.02.16.21251803.
Davies NG, Jarvis CI, Edmunds WJ, et al. Increased mortality in community-tested cases of SARS-CoV-2 lineage B.1.1.7. Nature. 2021;1–5. https://doi.org/10.1038/s41586-021-03426-1.
Zhao S, Lou J, Chong MKC, et al. Inferring the association between the risk of COVID-19 case fatality and N501Y substitution in SARS-CoV-2. Viruses. 2021;13. https://doi.org/10.3390/v13040638.
Ackland JA, Ackland GJ, Wallace DJ. Evolution of case fatality rates in the second wave of coronavirus in England: effects of false positives, a Variant of Concern and vaccination. medRxiv. 2021;2021.04.14.21255385. https://doi.org/10.1101/2021.04.14.21255385.
Pham TM, Tahir H, van de Wijgert JHHM, et al. Interventions to control nosocomial transmission of SARS-CoV-2: a modelling study. BMC Med. 2021;19:211. https://doi.org/10.1186/s12916-021-02060-y.
Article
CAS
PubMed
PubMed Central
Google Scholar
Seif F, Noorimotlagh Z, Mirzaee SA, et al. The SARS-CoV-2 (COVID-19) pandemic in hospital: an insight into environmental surfaces contamination, disinfectants’ efficiency, and estimation of plastic waste production. Environ Res. 2021;202:111809. https://doi.org/10.1016/j.envres.2021.111809.
Article
CAS
Google Scholar