Effectiveness of Immunoprophylaxis in Suppressing Carriage of Neisseria Meningitidis in the Military Environment

Abstract

Neisseria meningitidis, etiological factor of invasive meningococcal disease, is a human commensal that colonizes the nasopharynx. Colonization is usually asymptomatic, but it is a prerequisite for disease. Asymptomatic carriers are the major source of infection. In the present study, a survey of N. meningitidis carriage was conducted between January and March 2013 in a military unit in Poland. Single-time throat culture samples were collected from professional 559 soldiers (302 unvaccinated vs. 257 vaccinated individuals with the quadrivalent conjugate vaccine ACYW-135). Bacterial identification was performed with classic microbiological methods (culture, incubation, identification). Non-culture method (PCR) was used for confirmation of detected strains of N. meningitidis and determination of serogroups. We found 29 carriers in the group of unvaccinated soldiers (9.6 % of examined individuals) whereas among vaccinated soldiers only 3 persons were carriers of N. meningitidis (1.2 %). The most frequently identified serogroups among the carriers serving in the same military facility were serogroup B (28 %), followed by Y (25 %), and C (22 %). In conclusion, the initiation of mass vaccination with the quadrivalent conjugate vaccine ACYW-135 in the military environment seems an effective method of suppressing N. meningitidis carriage.

Observational study of nasopharyngeal carriage of Neisseria meningitidis in applicants to a military academy in the Russian Federation

“…This study identified a carriage prevalence of 16% for N. meningitidis in those entering a military college in the Russian Federation, and similar rates have been seen in recruits entering a military setting in Greece (15%) (Tryfinopoulou et al, 2016) and Poland (16-24%) (Tyski et al, 2001), with lower carriage rates seen for recruits entering a military setting in Turkey (4.2%) (Celal Basustaoglu et al, 2011) and Iran (8%) (Ataee et al, 2016) and professional soldiers in Poland (5.2% and 9.6%) (Korzeniewski et al, 2017;Korzeniewski et al, 2015). It was anticipated that the carriage rate would increase after recruitment while the recruits resided in a semi-closed environment as these populations are at higher risk for outbreaks of meningococcal disease (Aguilera et al, 2002;Brundage et al, 2002; National Foundation for Infectious Diseases (NFID), 2017); while a study of the change in carriage rate in students identified a rapid increase on entering university (Neal et al, 2000).…”

“…This study was also only conducted at 3 time points and was not a continuous longitudinal sampling study, and so provides only a limited understanding of the dynamics of carriage changes in this population, and cannot provide information on transmission patterns. Additionally, many of the isolates were ungroupable, which has been seen before in carrier studies (Caugant et al, 2006;Celal Basustaoglu et al, 2011;Glitza et al, 2008;Korzeniewski et al, 2015;Tyski et al, 2001) and previous evidence has shown challenges in serogrouping of isolates from carriage studies due to reduced or no capsule expression in the carriage state (Jones et al, 2016). Similarly genetic plasticity of the capsule can effect PCR assay sensitivity (Jones et al, 2016) and may have resulted in some of the discrepancy seen between the assays.…”

“…The UK has had a universal mass vaccination program with MenC vaccines since 1999, carriage studies before and after the initiation of the vaccination program demonstrated a significant reduction in meningococcal serogroup C carriage (Maiden et al, 2008). Regarding the military environment, a study in Poland has demonstrated the effectiveness of quadrivalent meningococcal conjugate vaccine in suppressing N. meningitidis carriage (Korzeniewski et al, 2015). Currently the Russian Federation does not have a mass vaccination program against N. meningitidis, surveillance of cases and carriage rates with the potential introduction of a vaccination program with serogroup ACYW vaccine may help to reduce carriage and outbreaks of meningococcal disease.…”

Rise in Group W Meningococcal Carriage in University Students, United Kingdom

“…Introduction of the MenC monovalent conjugate vaccines previously reduced carriage acquisition of MenC strains in adolescents and young adults ( 9 ). There is evidence, albeit limited, to suggest that the quadrivalent vaccine may have a similar effect on carriage of MenCWY strains ( 10 , 11 ). Reduced carriage in this population should lead to indirect protection of other age groups through herd immunity, thus enhancing the public health effect and cost-effectiveness of this approach.…”

Evaluation of Neisseria meningitidis Carriage with the Analysis of Serogroups, Genogroups and Clonal Complexes among Polish Soldiers

“…In Poland, there have been reports of IMD cases in recent years; however, the actual carriage incidence of N. meningitidis among Polish residents has not been determined (Jafri et al 2013). Many of Polish and European publications on the N. meningitidis carriage incidence are limited to military environment (Chapalain et al 1992;Tyski et al 2000;Korzeniewski et al 2015). According to the research findings, meningococcal carriage is high among conscripted soldiers serving in European armies, whereas among profes-sional soldiers it was found to be like the carriage rates observed in the general population (Korzeniewski et al 2017).…”