{"id":4898,"date":"2021-02-23T18:34:22","date_gmt":"2021-02-24T02:34:22","guid":{"rendered":"https:\/\/depts.washington.edu\/pandemicalliance\/?p=4898"},"modified":"2021-02-23T18:34:22","modified_gmt":"2021-02-24T02:34:22","slug":"single-dose-administration-and-the-influence-of-the-timing-of-the-booster-dose-on-immunogenicity-and-efficacy-of-chadox1-ncov-19-azd1222-vaccine-a-pooled-analysis-of-four-randomised-trials","status":"publish","type":"post","link":"https:\/\/depts.washington.edu\/pandemicalliance\/2021\/02\/23\/single-dose-administration-and-the-influence-of-the-timing-of-the-booster-dose-on-immunogenicity-and-efficacy-of-chadox1-ncov-19-azd1222-vaccine-a-pooled-analysis-of-four-randomised-trials\/","title":{"rendered":"Single-Dose Administration and the Influence of the Timing of the Booster Dose on Immunogenicity and Efficacy of ChAdOx1 NCoV-19 (AZD1222) Vaccine: A Pooled Analysis of Four Randomised Trials"},"content":{"rendered":"<p>Pooled analysis of four randomized placebo-controlled trials (total n=24,422) of the Oxford-AstraZeneca ChAdOx1 nCov-19 (AZD1222) vaccine show that overall efficacy against symptomatic SARS-CoV-2 infection &gt;14 days after the second dose was 66.7% (95%CI: 57.4-74.0%), with 84 cases (1% cumulative incidence) in the 8,597 participants in the vaccine group and 248 cases (2.9% cumulative incidence) in the 8,581 participants in the control group.<\/p>\n<p>Efficacy appears to have been greater when doses were administered \u226512 weeks apart. Among those receiving two standard doses, the vaccine efficacy after the second dose was 81.3% (95%CI: 60.3-91.2%) when doses were \u226512 weeks apart and 55.1% (95%CI: 33.0-69.9%) when doses were &lt;6 weeks apart. Exploratory analyses showed that vaccine efficacy after a single standard dose of vaccine from day 22 to day 90 after vaccination was 76.0% (59.3\u201385.9%)<\/p>\n<p>Participants included in this pooled analysis were from studies in the UK (COV001) and (COV002), Brazil (COV003), and South Africa (COV005). <i>[EDITORIAL NOTE: A pre-print version of this analysis was summarized in this report on February 3, 2021.]<\/i><\/p>\n<p><i>Voysey et al.\u00a0(Feb 19, 2021). Single-Dose Administration and the Influence of the Timing of the Booster Dose on Immunogenicity and Efficacy of ChAdOx1 NCoV-19 (AZD1222) Vaccine: A Pooled Analysis of Four Randomised Trials. The Lancet. <\/i><a href=\"https:\/\/doi.org\/10.1016\/S0140-6736(21)00432-3\">https:\/\/doi.org\/10.1016\/S0140-6736(21)00432-3<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Pooled analysis of four randomized placebo-controlled trials (total n=24,422) of the Oxford-AstraZeneca ChAdOx1 nCov-19 (AZD1222) vaccine show that overall efficacy against symptomatic SARS-CoV-2 infection &gt;14 days after the second dose was 66.7% (95%CI: 57.4-74.0%), with 84 cases (1% cumulative incidence) in the 8,597 participants in the vaccine group and 248 cases (2.9% cumulative incidence) in&#8230;<\/p>\n<div><a class=\"more\" href=\"https:\/\/depts.washington.edu\/pandemicalliance\/2021\/02\/23\/single-dose-administration-and-the-influence-of-the-timing-of-the-booster-dose-on-immunogenicity-and-efficacy-of-chadox1-ncov-19-azd1222-vaccine-a-pooled-analysis-of-four-randomised-trials\/\">Read more<\/a><\/div>\n","protected":false},"author":7,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":"","_links_to":"","_links_to_target":""},"categories":[6],"tags":[33],"topic":[31],"class_list":["post-4898","post","type-post","status-publish","format-standard","hentry","category-article-summary","tag-vaccines","topic-vaccines-and-immunity"],"_links":{"self":[{"href":"https:\/\/depts.washington.edu\/pandemicalliance\/wp-json\/wp\/v2\/posts\/4898","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/depts.washington.edu\/pandemicalliance\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/depts.washington.edu\/pandemicalliance\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/depts.washington.edu\/pandemicalliance\/wp-json\/wp\/v2\/users\/7"}],"replies":[{"embeddable":true,"href":"https:\/\/depts.washington.edu\/pandemicalliance\/wp-json\/wp\/v2\/comments?post=4898"}],"version-history":[{"count":1,"href":"https:\/\/depts.washington.edu\/pandemicalliance\/wp-json\/wp\/v2\/posts\/4898\/revisions"}],"predecessor-version":[{"id":4899,"href":"https:\/\/depts.washington.edu\/pandemicalliance\/wp-json\/wp\/v2\/posts\/4898\/revisions\/4899"}],"wp:attachment":[{"href":"https:\/\/depts.washington.edu\/pandemicalliance\/wp-json\/wp\/v2\/media?parent=4898"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/depts.washington.edu\/pandemicalliance\/wp-json\/wp\/v2\/categories?post=4898"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/depts.washington.edu\/pandemicalliance\/wp-json\/wp\/v2\/tags?post=4898"},{"taxonomy":"topic","embeddable":true,"href":"https:\/\/depts.washington.edu\/pandemicalliance\/wp-json\/wp\/v2\/topic?post=4898"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}