Safety and Immunogenicity of Meningococcal Groups A and C Polysaccharide Vaccine in Adults 18–60 years of age

Relevance . In the Russian Federation, despite the low incidence rate in 2020–2021, there are subjects where the incidence rate of meningococcal infection (MI) exceeds the national average by 2–9 times. MI often becomes fulminant with an extremely rapid development of symptoms up to infectious and toxic shock, which limits the possibility of providing specialized care. Less than 24 hours may pass between the appearance of the first symptoms (nonspecific, similar to ARVI) and the development of shock with a fatal outcome. To date, the most reliable way to protect against meningococcal infection is vaccination. However, the healthcare system until 2022 could use only one domestic vaccine with one serogroup A. Aims . To study the safety, reactogenicity and immunological efficacy of Meningococcal A+C polysaccharide vaccine, manufactured by Microgen, Russia, when used in persons aged 18 to 60 years. Materials and methods . The study included 100 people aged 18–60 years who met the inclusion criteria, the average age of the participants was 31.09 ±1.13 years. All study participants were evenly divided into two groups. The Meningo A+C® vaccine, Sanofi Pasteur, France (hereinafter referred to as MPV2 AC) was used as a comparison. PHA study was carried out using the test system «A set of diagnostic reagents for erythrocyte meningococcal polysaccharide groups A, B, C liquid according to TS 9388-004-68925985-10» manufactured by Bio-Diagnostics LLC, Russia (registration certificate No. FSR 2011/11185 dated 17.10.2011). Results and discussion . The results of the study assessing the reactogenicity and safety of the vaccine: in the first 7 days after vaccination, reactions were registered in 12.0% (95% CI: 5.62–23.80%) vaccinated with Meningococcal A+C polysaccharide vaccine, and in 10.0% (95% CI: 4.35–21.36%) in the comparison group, vaccinated with MPV2 AS. There was no statistically significant difference between the groups (p ≥ 0.05). Results of the study assessing the immunogenicity: on the 28 th day after single-dose immunization of the participants of the clinical trial, both in the group vaccinated with Meningococcal A+C polysaccharide vaccine, and in the control group (vaccinated with MPV2 AC), a statistically significant increase in antibody titer was noted, p ≤ 0.001: 76.0% (95% CI: 62.59–85.70%) versus 74.0% (95% CI: 60.45–84.13%) in the control group, χ2 =0.0533 and p=0.818.. Conclusions. Meningococcal A+C polysaccharide vaccine is characterized by safety,