■关于评估体液和细胞免疫反应的疫苗平台的头对头比较的全球数据有限,按疫苗接种前血清状况分层。印度18-45岁年龄组人群的COVID-19疫苗接种活动始于2021年4月,当时由于2021年4月至5月COVID-19大流行的三角洲浪潮,普通人群的血清阳性率正在上升。
■在2021年6月30日至2022年1月28日之间,我们在印度的四个临床站点招募了691名18-45岁年龄段的参与者。在这项非随机和实验室盲化研究中,根据国家疫苗接种政策,参与者接受两剂Covaxin®(间隔4周)或两剂Covishield™(间隔12周).主要结果是两次剂量后针对SARS-CoV-2峰值和核衣壳蛋白的抗体的血清转换率和几何平均滴度(GMT)。次要结果是接种前和接种后细胞免疫反应的频率。
■与疫苗接种前基线相比,两种疫苗在血清阴性和血清阳性个体中均引起统计学上显著的血清转换和结合抗体水平.在符合协议的队列中,Covishield™引发的抗体反应高于Covaxin®,通过血清转化率测量(98.3%vs74.4%,血清阴性个体p<0.0001;91.7%vs66.9%,在血清阳性个体中p<0.0001)以及针对祖先菌株的抗刺突抗体水平(GMT1272.1vs75.4结合抗体单位/ml[BAU/ml],血清阴性个体p<0.0001;2089.07vs585.7BAU/ml,血清阳性个体中p<0.0001)。由于所有临床站点的参与者都没有同时招募,相对于δ波和omicron波,位点特异性免疫原性受疫苗接种时间的影响.Covishield™接受者对包括delta和omicron在内的关注变体的替代中和抗体反应高于Covaxin®接受者;在疫苗接种和无症状感染(omicron变体)后,血清阳性的个体高于血清阴性的个体。仅从疫苗接种时间表在omicron波之前的四个位点队列中的一个报告T细胞应答。在有血清反应的个体中,Covishield™引发CD4+和CD8+尖峰特异性细胞因子产生T细胞,而Covaxin®引发主要CD4+尖峰特异性T细胞。两种疫苗均未显示血清阳性个体中的刺突特异性T细胞的显著接种后扩增。
■Covishield™在血清阴性个体和血清阳性个体中引发的免疫反应均高于Covaxin®,代表大多数接种疫苗的印度人群的疫苗接种前免疫史的队列。
■来自印度斯坦联合利华有限公司(HUL)和联合利华印度Pvt的企业社会责任(CSR)资金。有限公司(UIPL)。
UNASSIGNED: There are limited global data on head-to-head comparisons of vaccine platforms assessing both humoral and cellular immune responses, stratified by pre-vaccination serostatus. The COVID-19 vaccination drive for the Indian population in the age group 18-45 years began in April 2021 when seropositivity rates in the general population were rising due to the delta wave of COVID-19 pandemic during April-May 2021.
UNASSIGNED: Between June 30, 2021, and Jan 28, 2022, we enrolled 691 participants in the age group 18-45 years across four clinical sites in India. In this non-randomised and laboratory blinded study, participants received either two doses of Covaxin® (4 weeks apart) or two doses of Covishield™ (12 weeks apart) as per the national vaccination policy. The primary outcome was the seroconversion rate and the geometric mean titre (GMT) of antibodies against the SARS-CoV-2 spike and nucleocapsid proteins post two doses. The secondary outcome was the frequency of cellular immune responses pre- and post-vaccination.
UNASSIGNED: When compared to pre-vaccination baseline, both vaccines elicited statistically significant seroconversion and binding antibody levels in both seronegative and
seropositive individuals. In the per-protocol cohort, Covishield™ elicited higher antibody responses than Covaxin® as measured by seroconversion rate (98.3% vs 74.4%, p < 0.0001 in seronegative individuals; 91.7% vs 66.9%, p < 0.0001 in
seropositive individuals) as well as by anti-spike antibody levels against the ancestral strain (GMT 1272.1 vs 75.4 binding antibody units/ml [BAU/ml], p < 0.0001 in seronegative individuals; 2089.07 vs 585.7 BAU/ml, p < 0.0001 in seropositive individuals). As participants at all clinical sites were not recruited at the same time, site-specific immunogenicity was impacted by the timing of vaccination relative to the delta and omicron waves. Surrogate neutralising antibody responses against variants-of-concern including delta and omicron was higher in Covishield™ recipients than in Covaxin® recipients; and in
seropositive than in seronegative individuals after both vaccination and asymptomatic infection (omicron variant). T cell responses are reported from only one of the four site cohorts where the vaccination schedule preceded the omicron wave. In seronegative individuals, Covishield™ elicited both CD4+ and CD8+ spike-specific cytokine-producing T cells whereas Covaxin® elicited mainly CD4+ spike-specific T cells. Neither vaccine showed significant post-vaccination expansion of spike-specific T cells in
seropositive individuals.
UNASSIGNED: Covishield™ elicited immune responses of higher magnitude and breadth than Covaxin® in both seronegative individuals and
seropositive individuals, across cohorts representing the pre-vaccination immune history of most of the vaccinated Indian population.
UNASSIGNED: Corporate social responsibility (CSR) funding from Hindustan Unilever Limited (HUL) and Unilever India Pvt. Ltd. (UIPL).