Show simple item record

Files in this item


Item metadata

dc.contributor.authorKatikireddi, Srinivasa Vittal
dc.contributor.authorCerqueira-Silva, Thiago
dc.contributor.authorVasileiou, Eleftheria
dc.contributor.authorRobertson, Chris
dc.contributor.authorAmele, Sarah
dc.contributor.authorPan, Jiafeng
dc.contributor.authorTaylor, Bob
dc.contributor.authorBoaventura, Viviane
dc.contributor.authorWerneck, Guilherme Loureiro
dc.contributor.authorFlores-Ortiz, Renzo
dc.contributor.authorAgrawal, Utkarsh
dc.contributor.authorDocherty, Annemarie B
dc.contributor.authorMcCowan, Colin
dc.contributor.authorMcMenamin, Jim
dc.contributor.authorMoore, Emily
dc.contributor.authorRitchie, Lewis D
dc.contributor.authorRudan, Igor
dc.contributor.authorShah, Syed Ahmar
dc.contributor.authorShi, Ting
dc.contributor.authorSimpson, Colin R
dc.contributor.authorBarreto, Mauricio L
dc.contributor.authorOliveira, Vinicius de Araujo
dc.contributor.authorBarral-Netto, Manoel
dc.contributor.authorSheikh, Aziz
dc.identifier.citationKatikireddi , S V , Cerqueira-Silva , T , Vasileiou , E , Robertson , C , Amele , S , Pan , J , Taylor , B , Boaventura , V , Werneck , G L , Flores-Ortiz , R , Agrawal , U , Docherty , A B , McCowan , C , McMenamin , J , Moore , E , Ritchie , L D , Rudan , I , Shah , S A , Shi , T , Simpson , C R , Barreto , M L , Oliveira , V D A , Barral-Netto , M & Sheikh , A 2022 , ' Two-dose ChAdOx1 nCoV-19 vaccine protection against COVID-19 hospital admissions and deaths over time : a retrospective, population-based cohort study in Scotland and Brazil ' , The Lancet , vol. 399 , no. 10319 , pp. 25-35 .
dc.identifier.otherRIS: urn:00FA48346B9BEEACDD16F986D28635F9
dc.identifier.otherORCID: /0000-0002-9466-833X/work/105318628
dc.descriptionFunding : UK Research and Innovation (Medical Research Council), Scottish Government, Research and Innovation Industrial Strategy Challenge Fund, Health Data Research UK, Fiocruz, Fazer o Bem Faz Bem Programme; Conselho Nacional de Desenvolvimento Científico e Tecnológico, Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro.en
dc.description.abstractBackground Reports suggest that COVID-19 vaccine effectiveness is decreasing, but whether this reflects waning or new SARS-CoV-2 variants—especially delta (B.1.617.2)—is unclear. We investigated the association between time since two doses of ChAdOx1 nCoV-19 vaccine and risk of severe COVID-19 outcomes in Scotland (where delta was dominant), with comparative analyses in Brazil (where delta was uncommon). Methods In this retrospective, population-based cohort study in Brazil and Scotland, we linked national databases from the EAVE II study in Scotland; and the COVID-19 Vaccination Campaign, Acute Respiratory Infection Suspected Cases, and Severe Acute Respiratory Infection/Illness datasets in Brazil) for vaccination, laboratory testing, clinical, and mortality data. We defined cohorts of adults (aged ≥18 years) who received two doses of ChAdOx1 nCoV-19 and compared rates of severe COVID-19 outcomes (ie, COVID-19 hospital admission or death) across fortnightly periods, relative to 2–3 weeks after the second dose. Entry to the Scotland cohort started from May 19, 2021, and entry to the Brazil cohort started from Jan 18, 2021. Follow-up in both cohorts was until Oct 25, 2021. Poisson regression was used to estimate rate ratios (RRs) and vaccine effectiveness, with 95% CIs. Findings 1 972 454 adults received two doses of ChAdOx1 nCoV-19 in Scotland and 42 558 839 in Brazil, with longer follow-up in Scotland because two-dose vaccination began earlier in Scotland than in Brazil. In Scotland, RRs for severe COVID-19 increased to 2·01 (95% CI 1·54–2·62) at 10–11 weeks, 3·01 (2·26–3·99) at 14–15 weeks, and 5·43 (4·00–7·38) at 18–19 weeks after the second dose. The pattern of results was similar in Brazil, with RRs of 2·29 (2·01–2·61) at 10–11 weeks, 3·10 (2·63–3·64) at 14–15 weeks, and 4·71 (3·83–5·78) at 18–19 weeks after the second dose. In Scotland, vaccine effectiveness decreased from 83·7% (95% CI 79·7–87·0) at 2–3 weeks, to 75·9% (72·9–78·6) at 14–15 weeks, and 63·7% (59·6–67·4) at 18–19 weeks after the second dose. In Brazil, vaccine effectiveness decreased from 86·4% (85·4–87·3) at 2–3 weeks, to 59·7% (54·6–64·2) at 14–15 weeks, and 42·2% (32·4–50·6) at 18–19 weeks. Interpretation We found waning vaccine protection of ChAdOx1 nCoV-19 against COVID-19 hospital admissions and deaths in both Scotland and Brazil, this becoming evident within three months of the second vaccine dose. Consideration needs to be given to providing booster vaccine doses for people who have received ChAdOx1 nCoV-19.
dc.relation.ispartofThe Lanceten
dc.subjectRA0421 Public health. Hygiene. Preventive Medicineen
dc.subjectSDG 3 - Good Health and Well-beingen
dc.titleTwo-dose ChAdOx1 nCoV-19 vaccine protection against COVID-19 hospital admissions and deaths over time : a retrospective, population-based cohort study in Scotland and Brazilen
dc.typeJournal articleen
dc.contributor.institutionUniversity of St Andrews. School of Medicineen
dc.contributor.institutionUniversity of St Andrews. Population and Behavioural Science Divisionen
dc.contributor.institutionUniversity of St Andrews. Sir James Mackenzie Institute for Early Diagnosisen
dc.description.statusPeer revieweden

This item appears in the following Collection(s)

Show simple item record