Yadav Pragya D, Mohandas Sreelekshmy, Shete Anita, Sapkal Gajanan, Deshpande Gururaj, Kumar Abhimanyu, Wakchaure Kundan, Dighe Hitesh, Jain Rajlaxmi, Ganneru Brunda, Yemul Jyoti, Gawande Pranita, Vadrevu Krishna Mohan, Abraham Priya
Maximum Containment Facility, Indian Council of Medical Research-National Institute of Virology, Pune 411021, Maharashtra, India.
Diagnostic Virology Group, Indian Council of Medical Research-National Institute of Virology, Pune 411021, Maharashtra, India.
iScience. 2022 Oct 21;25(10):105178. doi: 10.1016/j.isci.2022.105178. Epub 2022 Sep 22.
The immunity acquired after natural infection or vaccinations against SARS-CoV-2 tend to wane with time. Here, we compared the protective efficacy of COVAXIN® following two- and three-dose immunizations against the Delta variant and also studied the efficacy of COVAXIN® against Omicron variants in a Syrian hamster model. Despite the comparable neutralizing antibody response against the homologous vaccine strain in both the two-dose and three-dose immunized groups, considerable reduction in the lung disease severity was observed in the 3 dose immunized group after Delta variant challenge. In the challenge study using the Omicron variants, i.e., BA.1.1 and BA.2, lesser virus shedding, lung viral load and lung disease severity were observed in the immunized groups. The present study shows that administration of COVAXIN® booster dose will enhance the vaccine effectiveness against the Delta variant infection and give protection against the BA.1.1 and BA.2 variants.
自然感染或接种针对严重急性呼吸综合征冠状病毒2（SARS-CoV-2）的疫苗后获得的免疫力往往会随着时间减弱。在此，我们比较了两剂和三剂COVAXIN®免疫接种针对德尔塔变种的保护效力，并在叙利亚仓鼠模型中研究了COVAXIN®针对奥密克戎变种的效力。尽管两剂和三剂免疫接种组针对同源疫苗株的中和抗体反应相当，但在德尔塔变种攻击后，三剂免疫接种组的肺部疾病严重程度显著降低。在使用奥密克戎变种即BA.1.1和BA.2进行的攻击研究中，免疫接种组的病毒脱落、肺部病毒载量和肺部疾病严重程度均较低。本研究表明，接种COVAXIN®加强剂将提高疫苗对德尔塔变种感染的效力，并对BA.1.1和BA.2变种提供保护。
