ANRS 0142s CoviCompare Mali

The aim of this vaccine trial is to assess the immunogenicity and safety of the Ad26.COV2.S vaccine, developed by Janssen, in populations in Mali: adults from different age groups, including older people.

Janssen’s Ad26.COV2.S vaccine is a non-replicating human adenovirus 26, modified to contain the SARS-CoV-2 spike protein, without adjuvants, and administered as a single dose (in accordance with the recommendations of Mali’s national vaccination campaign dated 20 January 2022).

The trial consists of a longitudinal analysis of the various components of the immune response induced by the Ad26.COV2.S vaccine in older adults compared with younger subjects. To this end, immunomonitoring was carried out using samples collected at different time points. Several parameters of humoral, cellular and mucosal immunity were measured using a battery of specific tests. The immunogenicity analysis will compare the immunological response at D0, M1, M2, M6, M12 and M24 between the age groups.

Two further CoviCompare trials have been initiated by ANRS MIE:

• ANRS 0002S CoviCompare-P, a national, open-label, phase II trial evaluating the immunogenicity and safety of the BNT162b2 COVID-19 mRNA vaccine;
• ANRS 0144S CoviCompare Guinea, a Phase II trial evaluating the immunogenicity and safety of the BBIBP-CorV vaccine in adult participants in Guinea.

Primary objective

The primary objective is to evaluate the vaccine-induced humoral immune response elicited by the Ad26.COV2 vaccine in adults; two months after completion of the full SARS-CoV-2 vaccination schedule.

Secondary objectives

• To characterise the humoral immune response induced by the Ad26.COV2.S vaccine (full vaccination schedule) at D0, M1, M2, M6, M12 and M24 across different age groups
• To assess and characterise the antigen-specific T-cell response in the different age groups
• To assess mucosal immunity to the vaccine in the different age groups (18 to 45 years, 55 to 64 years and 65 years and over)
• To characterise the B-cell humoral response to the vaccine in the different age groups
• To characterise mucosal immunity (functional study) and measure ultra–sensitive IgA levels in saliva using the photoreduction test across the different age groups.
• To assess the clinical safety of vaccination against SARS–CoV–2
• To record cases of SARS–CoV–2 infection among trial participants