Researchers from Ruijin Hospital Affiliated to Shanghai Jiao Tong University (SJTU) School of Medicine, et al. have conducted a study entitled “Host protection against Omicron BA.2.2 sublineages by prior vaccination in spring 2022 COVID-19 outbreak in Shanghai”. This study was published in Frontiers of Medicine, Volume 17, Issue 3.
The Omicron family of SARS-CoV-2 variants are currently driving the COVID-19 pandemic. Here this study analyzed the clinical laboratory test results of 9911 Omicron BA.2.2 sublineages-infected symptomatic patients without earlier infection histories during a SARS-CoV-2 outbreak in Shanghai in spring 2022. Compared to an earlier patient cohort infected by SARS-CoV-2 prototype strains in 2020, BA.2.2 infection led to distinct fluctuations of pathophysiological markers in the peripheral blood. In particular, severe/critical cases of COVID-19 post BA.2.2 infection were associated with less pro-inflammatory macrophage activation and stronger interferon alpha response in the bronchoalveolar microenvironment. Importantly, the abnormal biomarkers were significantly subdued in individuals who had been immunized by 2 or 3 doses of SARS-CoV-2 prototype-inactivated vaccines, supporting the estimation of an overall 96.02% of protection rate against severe/critical disease in the 4854 cases in BA.2.2 patient cohort with traceable vaccination records. Furthermore, even though age was a critical risk factor of the severity of COVID-19 post BA.2.2 infection, vaccination-elicited protection against severe/critical COVID-19 reached 90.15% in patients aged ≥ 60 years old. Together, this study delineates the pathophysiological features of Omicron BA.2.2 sublineages and demonstrates significant protection conferred by prior prototype-based inactivated vaccines.
This study was supported by the National Natural Science Foundation of China, the Natural Science Foundation of Shanghai, Shanghai Clinical Research Center for Hematologic Disease, Shanghai Major Project for Clinical Medicine, Shanghai Shenkang Hospital Development Center, Innovative Research Team of High-level Local Universities in Shanghai, and Shanghai Collaborative Innovation Program on Regenerative Medicine and Stem Cell Research. For more detailed information, the full paper is available at: https://journal.hep.com.cn/fmd/EN/10.1007/s11684-022-0977-3.