Study of the cellular and humoral immune responses to SARS-CoV-2 vaccination.

Our understanding of cellular immunity in response to COVID-19 infection or vaccination is limited because of less commonly used techniques. We investigated both the cellular and humoral immune responses before and after the administration of a third dose of the SARS-CoV-2 vaccine among a group of healthcare workers. Cellular immunity was evaluated using the VIDAS interferon-gamma (IFNγ) RUO test, which enables automated measurement of IFNγ levels after stimulating peripheral blood lymphocytes.

Low performance of interferon gamma release assay Quantiferon-TB gold coupled or not with Pst1/3/lipoglycan humoral detection to predict Mycobacterium tuberculosis complex disease in a low-burden area.

Whole T cell interferon gamma release assays such as QuantiFERON-TB Gold Plus (QTF-TB) are used to evaluate Mycobacterium tuberculosis complex (MTC) exposure but fail to discriminate latent tuberculosis infection (LTBI) from active disease. In this study conducted in a low-burden area, 1215 patients presenting MTC risk and tested both for QTF-TB and mycobacterial infection (microscopy, culture, and/or PCR) were selected, as well as 1298 controls screened with QTF-TB before medical recruitment. The humoral response (LIODetect®TB-ST) was further evaluated in 199 selected patients.

Antibody Titers and Protection against Omicron (BA.1 and BA.2) SARS-CoV-2 Infection.

The emergence of the SARS-CoV-2 variants of concern has greatly influenced the immune correlates of protection, and there are little data about the antibody threshold concentrations to protect against infection with SARS-CoV-2 Omicron BA.1 or BA.2.