Hamaluba Mainga, Sang Samuel, Orindi Benedict, Njau Irene, Karanja Henry, Kamau Naomi, Gitonga John N, Mugo Daisy, Wright Daniel, Nyagwange James, Kutima Bernadette, Omuoyo Donwilliams, Mwatasa Mwaganyuma, Ngetsa Caroline, Agoti Charles, Cheruiyot Stanley, Nyaguara Amek, Munene Marianne, Mturi Neema, Oloo Elizaphan, Ochola-Oyier Lynette, Mumba Noni, Mauncho Cynthia, Namayi Roselyne, Davies Alun, Tsofa Benjamin, Nduati Eunice W, Aliyan Nadia, Kasera Kadondi, Etyang Anthony, Boyd Amy, Hill Adrian, Gilbert Sarah, Douglas Alexander, Pollard Andrew, Bejon Philip, Lambe Teresa, Warimwe George
KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya.
Oxford Vaccine Group, University of Oxford, Oxford, England, UK.
Wellcome Open Res. 2023 Nov 27;8:182. doi: 10.12688/wellcomeopenres.19150.2. eCollection 2023.
There are limited data on the immunogenicity of coronavirus disease 2019 (COVID-19) vaccines in African populations. Here we report the immunogenicity and safety of the ChAdOx1 nCoV-19 (AZD1222) vaccine from a phase 1/2 single-blind, randomised, controlled trial among adults in Kenya conducted as part of the early studies assessing vaccine performance in different geographical settings to inform Emergency Use Authorisation.
We recruited and randomly assigned (1:1) 400 healthy adults aged ≥18 years in Kenya to receive ChAdOx1 nCoV-19 or control rabies vaccine, each as a two-dose schedule with a 3-month interval. The co-primary outcomes were safety, and immunogenicity assessed using total IgG enzyme-linked immunosorbent assay (ELISA) against SARS-CoV-2 spike protein 28 days after the second vaccination.
Between 28 October 2020 and 19 August 2021, 400 participants were enrolled and assigned to receive ChAdOx1 nCoV-19 (n=200) or rabies vaccine (n=200). Local and systemic adverse events were self-limiting and mild or moderate in nature. Three serious adverse events were reported but these were deemed unrelated to vaccination. The geometric mean anti-spike IgG titres 28 days after second dose vaccination were higher in the ChAdOx1 group (2773 ELISA units [EU], 95% CI 2447, 3142) than in the rabies vaccine group (61 EU, 95% CI 45, 81) and persisted over the 12 months follow-up. We did not identify any symptomatic infections or hospital admissions with respiratory illness and so vaccine efficacy against clinically apparent infection could not be measured. Vaccine efficacy against asymptomatic SARS-CoV-2 infection was 38.4% (95% CI -26.8%, 70.1%; p=0.188).
The safety, immunogenicity and efficacy against asymptomatic infection of ChAdOx1 nCoV-19 among Kenyan adults was similar to that observed elsewhere in the world, but efficacy against symptomatic infection or severe disease could not be measured in this cohort.
PAN-AFRICAN CLINICAL TRIALS REGISTRATION: PACTR202005681895696 (11/05/2020).
关于2019冠状病毒病（COVID-19）疫苗在非洲人群中的免疫原性数据有限。在此，我们报告ChAdOx1 nCoV-19（AZD1222）疫苗在肯尼亚成年人中进行的1/2期单盲、随机、对照试验的免疫原性和安全性，该试验是评估疫苗在不同地理环境中性能的早期研究的一部分，旨在为紧急使用授权提供依据。
我们招募并将肯尼亚400名年龄≥18岁的健康成年人随机分配（1:1），分别接种ChAdOx1 nCoV-19疫苗或对照狂犬病疫苗，均按两剂方案接种，间隔3个月。共同主要结局为安全性，以及在第二次接种后28天使用针对严重急性呼吸综合征冠状病毒2（SARS-CoV-2）刺突蛋白的总免疫球蛋白G（IgG）酶联免疫吸附测定（ELISA）评估免疫原性。
在2020年10月28日至2021年8月19日期间，400名参与者入组并被分配接受ChAdOx1 nCoV- vaccine（n=200）或狂犬病疫苗（n=200）。局部和全身不良事件为自限性，性质为轻度或中度。报告了3起严重不良事件，但这些事件被认为与疫苗接种无关。ChAdOx1组在第二次接种疫苗后28天的几何平均抗刺突IgG滴度（2773酶联免疫吸附测定单位[EU]，95%置信区间2447，3142）高于狂犬病疫苗组（61 EU，95%置信区间45，81），并在12个月的随访中持续存在。我们未发现任何有症状感染或因呼吸道疾病住院的情况，因此无法测量疫苗对临床明显感染的效力。疫苗对无症状SARS-CoV-2感染的效力为38.4%（95%置信区间-26.8%，70.1%；p=0.188）。
ChAdOx1 nCoV-19在肯尼亚成年人中的安全性、免疫原性以及对无症状感染的效力与世界其他地方观察到的情况相似，但在该队列中无法测量其对有症状感染或严重疾病的效力。
PACTR202005681895696（2020年5月11日）。
