Fig. 1: Study analysis workflow.

Figure 1 illustrates the definition of the 9 groups of individuals (grey square) and the workflow of their samples after selection. A total of 180 individuals were selected from the 3 cohorts and subdivided into 9 different sub-groups according to immunization status, each composed of 20 participants: i) convalescent patients after severe (severe WT, n = 20) or mild (mild WT, n = 20) COVID-19 during the first wave of the pandemic; ii) vaccinated convalescent individuals (after mild COVID-19 during the first wave of the pandemic) who received either one (WT/BNT, n = 20) or two (WT/BNT (2), n = 20) doses of the Pfizer BNT162b2 mRNA vaccine or one dose of the adenoviral-based vaccine ChadOx1 (WT/ChAdOx, n = 20; this group is designed as “hybrid immunity”); iii) COVID-19 naïve individuals fully vaccinated with two (BNT (2), n = 20) or three (BNT (3), n = 20) doses of BNT162b2 or one dose of ChadOx1 followed by one dose of BNT162b2 (ChAdOx/BNT, n = 20), and iv) individuals vaccinated with two or three doses of the BNT162b2 vaccine followed by a breakthrough infection during the Omicron BA.1 wave (BNT/WT, n = 20). System serology (green central square) approach was to analyze 6 different technologies. Database was managed by BIOASTER to generate results, graph, ease scientific communication and potentially inform public health offices and standards of care. WT: Wild type (Lineage B) variant of SARS-CoV-2. IgG levels include anti-NTD and anti-RBD (WT, BA.1). Created in BioRender. Reynaud, K. (2025) https://BioRender.com/ak4i172.