Previous coronavirus infection and COVID-19 vaccination alleviating severity and mortality. Both prior coronavirus infection and COVID-19 vaccination reduce disease severity and mortality. Neutralizing antibodies play a crucial role in protecting against severe illness. Some individuals cannot produce antibodies due to B-cell deficiency, which is responsible for antibody production. Among such individuals are patients with immunodeficiency and those with autoimmune diseases requiring rituximab treatment. Rituximab is an antibody against B-lymphocytes that depletes B-cells.
Scientists from the Ragon Institute at Massachusetts General Hospital, Massachusetts Institute of Technology, and Harvard investigated whether vaccination provides clinical benefits to patients with B-cell deficiency, given their heightened risk of severe COVID-19. The study involved 89 B-cell-deficient patients resulting from immunodeficiency or rituximab treatment for various autoimmune diseases.
After natural infection or vaccination, these patients did not produce antibodies to the coronavirus spike protein but heightened T-cell responses to the spike protein were observed. In B-cell-deficient patients treated with rituximab, there was a reduced frequency of circulating B-cells after coronavirus infection or vaccination, but not CD4+ and CD8+ T-cells. Compared to patients not receiving rituximab, effector T-cell responses to coronavirus proteins were higher in patients undergoing rituximab treatment.
The immune response after vaccination was vital in B-cell-deficient patients undergoing rituximab treatment. The response of memory CD4+ T-cells to the coronavirus spike protein was higher in vaccinated patients receiving rituximab but only in those who had not previously contracted COVID-19. Patients with immunodeficiency did not show an elevated response of memory CD4+ T-cells.
Even without antibodies to the spike protein, vaccination of patients undergoing rituximab treatment almost quintupled the reduced risk of hospitalization and severe COVID-19. The heightened response of memory may explain this CD8+ T-cells to the coronavirus. The restoration of antibodies, even in moderate titers, was associated with additional reductions in the severity of COVID-19 and mortality.
Conclusion
Vaccination of B-cell-deficient patients, even without antibodies, is linked to improved clinical outcomes in coronavirus infection. Vaccination almost quintupled the reduction in the risk of hospitalization and severe COVID-19. The reduced severity of COVID-19 lies in the enhanced T-cell response to SARS-CoV-2 infection and vaccination in B-cell-deficient patients.
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