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. 2022 May 14;10(5):778.
doi: 10.3390/vaccines10050778.

Evaluation of Meningococcal Serogroup C Bactericidal Antibodies after Primary Vaccination: A Multicentre Study, Italy

Affiliations

Evaluation of Meningococcal Serogroup C Bactericidal Antibodies after Primary Vaccination: A Multicentre Study, Italy

Arianna Neri et al. Vaccines (Basel). .

Abstract

Here, we evaluated over time in different cohorts of children vaccinated against serogroup C Neisseria meningitidis, the presence of antibodies with neutralizing activity. A total of 348 sera samples of enrolled children by year since vaccination (<1 year- up to 5 years), starting from February 2016 to December 2017, were collected in three collaborating centers. Meningococcal serogroup C (MenC) antibody titers were measured with a serum bactericidal antibody (SBA) assay using rabbit complement (rSBA) following standard operating procedures. The cut-off of rSBA titer ≥ 8 is considered the correlate of protection. We observed a significantly declining of bactericidal rSBA titers by 23% every year, for every 1-year from vaccination (Adjusted PR = 0.77, 95% CI: 0.71−0.84). The proportions of children with bactericidal antibodies, immunized with the meningococcal serogroup C conjugate (MCC) vaccine, declined from 67.7% (95% CI: 48.6−83.3%) one year after vaccination, to 36.7% (95% CI: 19.9−56.1%) five years after vaccination (chi-square for linear trend, p < 0.001). Children vaccinated with the tetravalent meningococcal serogroup ACWY vaccine resulted in a high proportion of bactericidal rSBA MenC titer ≥ 1:8 (90.6%, 95% CI: 79.3−96.9%) after a mean time of seven months. Overall, the results provide some evidences on the evaluation of meningococcal serogroup C bactericidal antibodies after primary vaccination.

Keywords: Neisseria meningitidis; bactericidal antibody; meningococcal conjugate vaccine.

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Conflict of interest statement

The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.

Figures

Figure 1
Figure 1
Percentage of children with MenC rSBA titers ≥ 8 by age at enrollment post MCC vaccine.
Figure 2
Figure 2
Percentage of children with serogroup C rSBA titers of ≥1:8 over time after MCC vaccination.

References

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