by Scientists have been closely studying the immune response of individuals who have experienced breakthrough infections of the omicron variant of SARS-CoV-2. It has been observed that the immune system of those who have encountered breakthrough infections by the omicron variant develops enhanced immunity against future versions of the virus. This finding is crucial in the fight against the never-ending emergence of new SARS-CoV-2 variants.
A team of South Korean scientists, led by Professor Shin Eui-Cheol of the Korea Virus Research Institute Center for Viral Immunology within the Institute for Basic Science (IBS), conducted a study to investigate the changes that occur in the immune system following post-vaccination breakthrough infections. The researchers focused specifically on memory T cells that form after omicron infections.
The omicron variant, which emerged in late 2021, has proven to be highly transmissible compared to its predecessors, making it the dominant strain in 2022 and leading to breakthrough infections despite vaccination efforts. New strains of the omicron variant, including BA.1, BA.2, BA.4/BA.5, BQ.1, and XBB, have continued to emerge, posing ongoing challenges in managing the pandemic.
After infection or vaccination, the body produces neutralizing antibodies and memory T cells in response to the virus. Neutralizing antibodies help prevent the virus from infecting host cells, while memory T cells quickly identify and eliminate infected cells, preventing the progression of the infection into severe disease.
The researchers selected patients who had suffered and recovered from BA.2 omicron breakthrough infections in early 2022 as subjects. They focused on the patients’ memory T cells and their ability to respond to different omicron variants, including BA.2, BA.4/BA.5, and others.
The subjects’ immune cells were isolated from their peripheral blood, and the researchers measured the cytokine production and anti-viral activities of the memory T cells in response to spike proteins from different variants. The results showed that the memory T cells from these patients exhibited heightened responses not only to the BA.2 strain but also to the later BA.4 and BA.5 strains of omicron. This indicates that their immune systems were strengthened after experiencing breakthrough infections, enabling them to better combat future variants of the same virus.
Furthermore, the research team identified a specific region of the spike protein that contributed to the enhanced response of the memory T cells. This discovery suggests that individuals who have experienced breakthrough infections by the omicron variant are less likely to develop severe COVID-19 symptoms from future emerging variants.
Jung Min Kyung, the lead researcher, stated that this finding provides new insights in the era of endemic COVID-19. She explained that our bodies have adapted to the constant emergence of new virus variants, equipping us to combat future strains of the virus.
Director Shin Eui-Cheol of the Center for Viral Immunology emphasized that this discovery could also be valuable in vaccine development. By identifying common features among the current dominant strain and emerging new strains, there may be opportunities to induce memory T cell defenses against subsequent variants.
The study was conducted in collaboration with colleagues from Yonsei University Severance Hospital, Korea University Hospital, Sungkyunkwan University, and Samsung Medical Center. These findings offer hope in understanding and adapting to the evolving immune response in the post-omicron era.
*Note:
1. Source: Coherent Market Insights, Public sources, Desk research
2. We have leveraged AI tools to mine information and compile it
