小柯机器人

英国牛津大学Maheshi N Ramasamy团队研究了ChAdOx1-nCoV-19（AZD1222）疫苗对SARS-CoV-2突变株B.1.1.7的疗效。2021年3月30日，该研究在线发表在《柳叶刀》上。

自2020年11月起，SARS-CoV-2的一个新突变株B.1.1.7成为英国COVID-19的主要病因。研究组报告了腺病毒载体疫苗ChAdOx1-nCoV-19（AZD1222）针对该突变株疗效的事后分析。

研究组招募在英国参加临床2/3期疫苗效力研究的志愿者（年龄≥18岁），将他们按1：1随机分配，分别接种ChAdOx1 nCoV-19或脑膜炎球菌结合物对照（Menawy）疫苗。如果他们出现COVID-19疾病症状（咳嗽、发烧37.8℃或更高、呼吸急促、嗅觉丧失或味觉丧失），则每周采集上呼吸道拭子，检测中和抗体反应。疗效分析包括在第二次接种疫苗后14天以上血清阴性、NAAT阳性拭子的受试者中有症状的COVID-19。根据接种的疫苗对受试者进行分析。

参与者于2020年5月31日至11月13日期间接种，并在2020年8月3日至12月30日期间接种增强剂量。在8534名主要疗效队列参与者中，6636名（78%）年龄在18-55岁之间，5065名（59%）为女性。2020年10月1日至2021年1月14日期间，共有520名参与者感染了SARS-CoV-2。

在试验期间，研究组从这些参与者身上收集了1466个NAAT阳性的鼻拭子和咽拭子。其中311名参与者的401个拭子被成功测序。疫苗诱导抗体对B.1.1.7突变株的实验室病毒中和活性低于对维多利亚系，几何平均比值为8.9。对于B.1.1.7和非B.1.1.7谱系，临床疫苗对症状性NAAT阳性感染的有效性分别为70.4%和81.5%。

研究结果表明，虽然ChAdOx1-nCoV-19在体外对B.1.1.7突变株的中和活性低于非B.1.1.7突变株，但疫苗对SARS-CoV-2的B.1.1.7突变株显示出有效性。

附：英文原文

Title: Efficacy of ChAdOx1 nCoV-19 (AZD1222) vaccine against SARS-CoV-2 variant of concern 202012/01 (B.1.1.7): an exploratory analysis of a randomised controlled trial

Author: Katherine R W Emary, Tanya Golubchik, Parvinder K Aley, Cristina V Ariani, Brian Angus, Sagida Bibi, Beth Blane, David Bonsall, Paola Cicconi, Sue Charlton, Elizabeth A Clutterbuck, Andrea M Collins, Tony Cox, Thomas C Darton, Christina Dold, Alexander D Douglas, Christopher J A Duncan, Katie J Ewer, Amy L Flaxman, Saul N Faust, Daniela M Ferreira, Shuo Feng, Adam Finn, Pedro M Folegatti, Michelle Fuskova, Eva Galiza, Anna L Goodman, Catherine M Green, Christopher A Green, Melanie Greenland, Bassam Hallis, Paul T Heath, Jodie Hay, Helen C Hill, Daniel Jenkin, Simon Kerridge, Rajeka Lazarus, Vincenzo Libri, Patrick J Lillie, Catherine Ludden, Natalie G Marchevsky, Angela M Minassian, Alastair C McGregor, Yama F Mujadidi, Daniel J Phillips, Emma Plested, Katrina M Pollock, Hannah Robinson, Andrew Smith, Rinn Song, Matthew D Snape, Rebecca K Sutherland, Emma C Thomson, Mark Toshner, David P J Turner, Johan Vekemans, Tonya L Villafana, Christopher J Williams, Adrian V S Hill, Teresa Lambe, Sarah C Gilbert, Merryn Voysey, Maheshi N Ramasamy, Andrew J Pollard

Issue&Volume: 2021-03-30

Abstract: Background

A new variant of SARS-CoV-2, B.1.1.7, emerged as the dominant cause of COVID-19 disease in the UK from November, 2020. We report a post-hoc analysis of the efficacy of the adenoviral vector vaccine, ChAdOx1 nCoV-19 (AZD1222), against this variant.

Methods

Volunteers (aged ≥18 years) who were enrolled in phase 2/3 vaccine efficacy studies in the UK, and who were randomly assigned (1:1) to receive ChAdOx1 nCoV-19 or a meningococcal conjugate control (MenACWY) vaccine, provided upper airway swabs on a weekly basis and also if they developed symptoms of COVID-19 disease (a cough, a fever of 37·8°C or higher, shortness of breath, anosmia, or ageusia). Swabs were tested by nucleic acid amplification test (NAAT) for SARS-CoV-2 and positive samples were sequenced through the COVID-19 Genomics UK consortium. Neutralising antibody responses were measured using a live-virus microneutralisation assay against the B.1.1.7 lineage and a canonical non-B.1.1.7 lineage (Victoria). The efficacy analysis included symptomatic COVID-19 in seronegative participants with a NAAT positive swab more than 14 days after a second dose of vaccine. Participants were analysed according to vaccine received. Vaccine efficacy was calculated as 1relative risk (ChAdOx1 nCoV-19 vs MenACWY groups) derived from a robust Poisson regression model. This study is continuing and is registered with ClinicalTrials.gov, NCT04400838, and ISRCTN, 15281137.

Findings

Participants in efficacy cohorts were recruited between May 31 and Nov 13, 2020, and received booster doses between Aug 3 and Dec 30, 2020. Of 8534 participants in the primary efficacy cohort, 6636 (78%) were aged 18–55 years and 5065 (59%) were female. Between Oct 1, 2020, and Jan 14, 2021, 520 participants developed SARS-CoV-2 infection. 1466 NAAT positive nose and throat swabs were collected from these participants during the trial. Of these, 401 swabs from 311 participants were successfully sequenced. Laboratory virus neutralisation activity by vaccine-induced antibodies was lower against the B.1.1.7 variant than against the Victoria lineage (geometric mean ratio 8·9, 95% CI 7·2–11·0). Clinical vaccine efficacy against symptomatic NAAT positive infection was 70·4% (95% CI 43·6–84·5) for B.1.1.7 and 81·5% (67·9–89·4) for non-B.1.1.7 lineages.

Interpretation

ChAdOx1 nCoV-19 showed reduced neutralisation activity against the B.1.1.7 variant compared with a non-B.1.1.7 variant in vitro, but the vaccine showed efficacy against the B.1.1.7 variant of SARS-CoV-2.

DOI: 10.1016/S0140-6736(21)00628-0

Source: https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(21)00628-0/fulltext

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