Study Evaluates Meningococcal Vaccine Safety and Effectiveness

Overview of Meningococcal Disease

A recent study has examined the safety and effectiveness of the meningococcal vaccine (4CMenB) in children and adolescents, contrasting it with other available vaccines. Meningitis, a severe disease caused by the bacterium Neisseria meningitidis, results in approximately 1.2 million cases and 135,000 deaths globally each year. Among the thirteen known meningococcal serogroups, Neisseria meningitidis serogroup B (MenB) is the leading cause of bacterial meningitis and sepsis in Europe, with a mortality rate of 10%.

Development of Meningococcal Vaccines

Efforts to create an effective vaccine against multiple MenB strains date back to the early 1980s but have faced challenges due to the unique properties of the pathogen. Currently, there are two protein-based vaccines: FHbp, which has been approved in the USA and Europe, and 4CMenB, which has received approval in over 35 countries. The FHbp vaccine targets two MenB strains, while 4CMenB is a tetravalent vaccine designed to combat four MenB strains: 5/99, 44/76-SL, M10713, and NZ98/254.

Meta-Analysis of 4CMenB Vaccine

Due to limited data on the efficacy of the 4CMenB vaccine in younger populations, Italian researchers conducted a meta-analysis published in The Lancet Infectious Diseases. They reviewed literature up to June 2017, focusing on articles that evaluated the immunogenicity and safety of 4CMenB compared to other meningococcal vaccines in children and adolescents. Key parameters analyzed included patient demographics, vaccination status, incidence of adverse effects, and seroconversion rates.

Immunogenicity Assessment

To evaluate the immunogenicity of the 4CMenB vaccine, researchers gathered data on antibody levels in study participants 30 days post-primary immunization (three doses for children, two doses for adolescents), after booster doses, and six months following primary immunization. Adverse effects were monitored by collecting reports on injection-site pain, fever, local reactions, systemic reactions (such as sleepiness and nausea), and serious adverse events leading to disability or hospitalization.

Findings from the Meta-Analysis

Of the 706 articles initially screened, 20 met the eligibility criteria for inclusion in the meta-analysis. The results revealed that 30 days after the primary immunization with 4CMenB, seroconversion rates for infants under two months, children, and adolescents ranged from 84% to 100%. Immunogenicity before booster doses varied by MenB strain, with rates between 23% and 99%. After administering the booster dose, the immunogenicity increased to over 93% for all strains. Six months post-immunization, persistence of immunogenicity was recorded at 100% for the 5/99 strain, 67% for the 44/76-SL strain, and 25% for the NZ98/254 strain, while adolescents showed rates exceeding 77% for all tested strains.

Safety Profile of 4CMenB

Most reported adverse events occurred within seven to ten days post-immunization, with no deaths recorded among those receiving the 4CMenB vaccine. A total of 39 serious adverse events were noted, primarily consisting of febrile convulsions and arthritis. The incidence rates for serious adverse events were 5.4 per 1000 individuals vaccinated with 4CMenB, compared to 2.5 per 1000 for those receiving recombinant MenB vaccines and 1.2 per 1000 for other meningococcal vaccines. Statistically significant differences indicated that the 4CMenB vaccine resulted in a higher risk of serious adverse effects compared to control vaccines, alongside increased occurrences of mild to moderate events like injection-site pain and fever.

Study Limitations and Conclusions

The authors acknowledged substantial heterogeneity in the data and emphasized the presence of limitations. It remains unclear whether the 4CMenB vaccine will provide adequate immunity against diverse strains, particularly during outbreaks. Further research is necessary to determine its effectiveness against other meningococcal serogroups, as observed with other vaccines.

In conclusion, the 4CMenB vaccine demonstrates an acceptable short-term safety profile and substantial immunogenicity. The primary immunization series is adequate for eliciting a robust immune response within 30 days among children and adolescents. However, a booster dose is essential for children to enhance protection against the M10713 strain, and long-term immunogenicity against the NZ98/254 strain remains suboptimal. Overall, researchers believe that this new meningococcal vaccine could serve as a vital tool in combating the risks associated with meningitis.

Reference

Flacco M E, Manzoli L, Rosso A, Marzuillo C, Bergamini M, Stefanati A, Cultrera R, Villari P, Ricciardi W, Ioannidis J P A, Contopoulos-Ioannidis D G. Immunogenicity and safety of the multicomponent meningococcal B vaccine (4CMenB) in children and adolescents: a systematic review and meta-analysis. The Lancet. 2018; v.18: 461 – 472.

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