Long‐term immune changes after COVID ‐19 and the effect of BCG vaccination and latent infections on disease severity
Year: 2025
Type: article
Study design: Observational Study
Abstract: ABSTRACT Background Several years after the COVID-19 pandemic, the role of trained immunity in COVID-19 remains controversial, and questions regarding the long-term effects of COVID-19 on immune cells remain unresolved. We investigated the roles of Bacillus Calmette–Guérin (BCG) vaccination and latent infections in the progression of COVID-19 and sepsis. Methods We conducted a prospective analysis of 97 individuals recovering from mild-to-critical COVID-19 and 64 sepsis patients. Immune cell frequencies, expression of functional markers, and plasma titres of anti- Toxoplasma gondii /cytomegalovirus/BCG antibodies were assessed and their impact on disease severity and outcomes were determined. To examine monocyte responses to secondary challenge, monocytes isolated from COVID-19 convalescent patients, BCG vaccinated and unvaccinated volunteers were stimulated with SARS-CoV-2 and LPS. Results Post COVID-19 patients showed immune dysregulation regardless of disease severity characterized mainly by altered expression of activation and functional markers in myeloid (CD39, CD64, CD85d, CD11b) and lymphoid cells (CD39, CD57, TIGIT). Strikingly, post-critical COVID-19 patients showed elevated expression of CD57 in CD8 + T cells compared to other severity groups. Additionally, a higher frequency of CMV and T. gondii seropositive-alongside a lower frequency of BCG seropositive-patients were associated with severe and critical COVID-19. However, the monocyte response to stimulation was unaffected by the severity of COVID-19. Conclusion These findings highlight the long-term alterations of immune cells in post-COVID-19 patients emphasizing the substantial impact of COVID-19 on immune function. However, our data showed no relationship between previous BCG vaccination and protection against SARS-CoV-2 infection.
DOI: 10.1002/cti2.70041
Authors: Kamila Bendíčková, Ioanna Papatheodorou, Gabriela Blažková, Martin Helán, Michaela Haláková, Petr Bednář, Erin Spearing, Lucie Obermannová, Julie Štíchová, Monika Dvořáková Heroldová, Tomáš Tomáš, Roman Panovský, Vladimír Šrámek, Marco De Zuani, Marcela Vlková, Daniel Růžek, Marcela Hortová‐Kohoutková, Jan Frič
Institutions: Masaryk University, International Clinical Research Center, St. Anne's University Hospital Brno, St. Anne's University Hospital Brno, University of South Bohemia in České Budějovice, Veterinary Research Institute, Institute of Parasitology, Czech Academy of Sciences, Biology Centre, Institute of Haematology and Blood Transfusion
Language: English
Subfield: Immunology
Field: Immunology and Microbiology
Domain: Life Sciences
Open Access status: gold
Estimated APC paid: $3,070
Award: G7888385751
OpenAlex ID: W4411738718