Immunogenicity and safety of two doses of the four-component recombinant meningococcal B (4CMenB) vaccine in adults with immunodeficiency

BACKGROUND: Individuals with immunodeficiency are at a higher risk of invasive meningococcal disease, but only a few studies have investigated the immunogenicity and safety of four-component recombinant meningococcal B (4CMenB) in this population. METHODS: This was a prospective, open-label, single-arm, single-center study with the aim to assess immunogenicity, reactogenicity and safety of two doses of 4CMenB in adults with acquired immunodeficiency: haematopoietic cell transplantation recipients, people living with HIV and patients candidates for/in treatment with biological drugs, such as monoclonal anti-CD20 antibodies. The primary objective was to evaluate the immunogenicity with the following endpoints: (i) geometric mean fold rise (GMFR) defined as a ratio of post-dose 2 geometric mean titres (GMTs) to baseline pre-dose 1 GMTs; (ii) proportion of subjects with 4-fold or greater increase in human complement serum bactericidal antibody assay (hSBA) from baseline to post-dose 2 and (iii) proportion of subjects with post-dose 2 hSBA titres ≥1:4. The secondary objective was to assess the reactogenicity, tolerability and safety. The trial was registered with clinicaltrials.gov (NCT04295733). RESULTS: A total of 65 patients were collected both blood samples and returned ≥1 safety diary. There was a significant (P < 0.001) increase in GMTs independently of the study group and antigen with the corresponding GMFR ranging from 11.9 to 105. The proportion of subjects with hSBA titres ≥1:4 increased significantly and 89.2-98.5% of subjects were deemed seroprotected. Seroconversion rates were similarly high: 78.5-87.7%. The injection-site pain was the most common adverse event (AE). No serious AEs were reported. CONCLUSIONS: 4CMenB was immunogenic and well-tolerated in adults with immunodeficiency.