Translational Health Science and Technology Institute, Faridabad, Haryana 120001, India.
ESIC Medical College and Hospital, Faridabad, Haryana, India.
EBioMedicine. 2022 Apr;78:103938. doi: 10.1016/j.ebiom.2022.103938. Epub 2022 Mar 16.
Rapid spread of the omicron SARS-CoV-2 variant despite extensive vaccination suggests immune escape. The neutralising ability of different vaccines alone or with natural SARS-CoV-2 infection against omicron is not well-known.
In this cross-sectional study, we tested the ability of vaccine and natural infection induced antibodies to neutralise omicron variant in a live virus neutralisation assay in four groups of individuals: (i) ChAdOx1 nCoV-19 vaccination, (ii) ChAdOx1 nCoV-19 vaccination plus prior SARS-CoV-2 infection, (iii) vaccination with inactivated virus vaccine (BBV152), and (iv) BBV152 vaccination plus prior SARS-CoV-2 infection. Primary outcome was fold-change in virus neutralisation titre against omicron compared with ancestral virus.
We included 80 subjects. The geometric mean titre (GMT) of the 50% focus reduction neutralisation test (FRNT50) was 380·4 (95% CI: 221·1, 654·7) against the ancestral virus with BBV152 vaccination and 379·3 (95% CI: 185·6, 775·2) with ChAdOx1 nCov-19 vaccination alone. GMT for vaccination plus infection groups were 806·1 (95% CI: 478·5, 1357·8) and 1526·2 (95% CI: 853·2, 2730·0), respectively. Against omicron variant, only 5 out of 20 in both BBV152 and ChAdOx1 nCoV-19 vaccine only groups, 6 out of 20 in BBV152 plus prior SARS-CoV-2 infection group, and 9 out of 20 in ChAdOx1 nCoV-19 plus prior SARS-CoV-2 infection group exhibited neutralisation titres above the lower limit of quantification (1:20) suggesting better neutralisation with prior infection. A reduction of 26·6 and 25·7 fold in FRNT50 titres against Omicron compared to ancestral SARS-CoV-2 strain was observed for individuals without prior SARS-CoV-2 infection vaccinated with BBV152 and ChAdOx1 nCoV-19, respectively. The corresponding reduction was 57·1 and 58·1 fold, respectively, for vaccinated individuals with prior infection. The 50% neutralisation titre against omicron demonstrated moderate correlation with serum anti-RBD IgG levels [Spearman r: 0·58 (0·41, 0·71)].
Significant reduction in the neutralising ability of both vaccine-induced and vaccine plus infection-induced antibodies was observed for omicron variant which might explain immune escape.
Department of Biotechnology, India; Bill & Melinda Gates Foundation, USA.
尽管广泛接种疫苗，奥密克戎 SARS-CoV-2 变体仍迅速传播，这表明其具有免疫逃逸能力。单独使用不同疫苗或自然感染 SARS-CoV-2 产生的中和抗体对奥密克戎的中和能力尚不清楚。
在这项横断面研究中，我们使用活病毒中和试验检测了以下四组个体中疫苗和自然感染诱导的抗体对奥密克戎变异株的中和能力：（i）接种 ChAdOx1 nCoV-19，（ii）接种 ChAdOx1 nCoV-19 并先前感染 SARS-CoV-2，（iii）接种灭活病毒疫苗（BBV152），以及（iv）接种 BBV152 并先前感染 SARS-CoV-2。主要结局是与原始病毒相比，针对奥密克戎的病毒中和滴度的变化倍数。
我们纳入了 80 名受试者。BBV152 接种组和 ChAdOx1 nCov-19 单独接种组的 50%焦点减少中和试验（FRNT50）几何平均滴度（GMT）分别为 380.4（95%CI：221.1，654.7）和 379.3（95%CI：185.6，775.2）。接种加感染组的 GMT 分别为 806.1（95%CI：478.5，1357.8）和 1526.2（95%CI：853.2，2730.0）。在奥密克戎变异株中，只有 20 名 BBV152 和 ChAdOx1 nCoV-19 疫苗接种组中的 5 名，BBV152 加先前 SARS-CoV-2 感染组中的 6 名，以及 ChAdOx1 nCoV-19 加先前 SARS-CoV-2 感染组中的 9 名，中和滴度高于定量下限（1:20），这表明先前感染的中和效果更好。与原始 SARS-CoV-2 株相比，未感染 SARS-CoV-2 的 BBV152 和 ChAdOx1 nCoV-19 疫苗接种个体的 FRNT50 滴度对奥密克戎的降低分别为 26.6 和 25.7 倍。对于有感染史的接种个体，相应的降低分别为 57.1 和 58.1 倍。对奥密克戎的 50%中和滴度与血清抗 RBD IgG 水平呈中度相关[Spearman r：0.58（0.41，0.71）]。
奥密克戎变异株对疫苗诱导和疫苗加感染诱导的中和抗体的中和能力显著降低，这可能解释了其免疫逃逸能力。
印度生物技术部；美国比尔及梅琳达·盖茨基金会。
