Getting Vaccinated: Meningococcal Disease in Georgia and Maryland High Schools

Bacterial meningitis is a result of pathogens H. influenzae, S. pneumoniae, L. monocytogenes or N.meningitidis. These pathogens infiltrate the host central nervous system (CNS) and cause inflammation. The host CNS is unequipped to combat bacterial pathogens, and activation of host inflammatory pathways leads to damage of the neurons.1

Meningococcal disease can develop from meningitis due to N. meningitidis in the lining of the brain and spinal cord and is spread through exchange of respiratory secretions like saliva. A severe case of meningococcal disease can lead to disabilities and death. The best preventative measure against the disease is the vaccine. Two vaccines currently available in the United States are meningococcal polysaccharide vaccine (Menomune®) and meningococcal conjugate vaccine MCV4 DT (Menactra®, Menveo® and MenHibrix®). The CDC recommends all adolescents between ages 16-21 receive the vaccine, as this group is at highest risk. Most colleges require new enrollees have a booster of the vaccine to prevent transmission among students.2

Title: Meningococcal Carriage Among Georgia and Maryland High School Students 3
Design Prospective cohort study; N = 3,311
Objective To measure the impact of meningococcal conjugate vaccine on serogroup Y meningococcal carriage
Study Groups Two high schools (1,731 students) received a diphtheria toxoid as the protein carrier (MCV4 DT) at the beginning of the study, and two high schools (1,543 students) received MCV4 DT at the end of the study.
Methods Students were enrolled from four different high schools in either Georgia or Maryland. A pharyngeal swab specimen was obtained to determine serotype with PCR. A free immunization with a single IM dose of MCV4 DT was offered to unvaccinated students either at the initial survey (within two months of start of school year) or the final survey (control group, three to seven months later) based on randomization. SAS 9.3 and Fisher exact test were used to compare the PCRs and proportions of students carrying serogroup Y in vaccination schools versus control schools.
Duration 2006-2007
Primary Outcome Measure The development of serotype Y carriage after vaccination with MCV4 DT
Baseline Characteristics Median age = 16 years, equal representation from all grades, 45.2% male, 61.6% white

Baseline characteristics were comparable between students in vaccination and control schools.

There were significantly more students in control schools who were white (p = 0.002), smokers (p = 0.004), and had fathers with less education (p = 0.03).

The proportions of students with carriage of serogroup Y strains at baseline in the vaccination and control schools were 0.35% and 0.19%, respectively (p = 0.51).

Results By the final survey, the overall carriage prevalence of serogroup Y in Maryland was 5.91%, compared with 2.63% in Georgia (P < .0001). Over the 3 survey rounds, the prevalence of serogroup Y carriage did not change substantially in either group. In an analysis of genotypic group Y carriage, ten students in the vaccinated schools and ten students in the control schools acquired genotypic group Y carriage over the three survey rounds (RR =  0.89; 95% CI, 0.34–2.31).
Adverse Events Common Adverse Events: N/A
Serious Adverse Events: N/A
Percentage that Discontinued due to Adverse Events: N/A
Study Author Conclusions The prevalence of meningococcal carriage among Georgia and Maryland high school students was around 3%. The carriage that was found was caused mostly by commensal meningococci that were not expressing capsule and were therefore unlikely to cause invasive disease. The low prevalence of carriage of meningococci observed in this study may underlie the dramatic declines in disease incidence, through natural immunity and reduced transmission. Smoking was a risk factor for carriage. The enrollment size of approximately 3300 students was low. The study did not have sufficient statistical power to assess the impact of MCV4-DT on carriage.

This study done in adolescents aged 16-21 on the effects of being vaccinated with MCV4-DT has clinical importance due to the high risk of transmission in this age group. However, the study population was not large enough to have sufficient statistical power to detect an impact of MCV4-DT vaccination on carriage of meningococcal serogroup Y. Though the study results suggest there was no difference in carriage between the vaccinated and control groups of students, the clinical worth of this conclusion cannot be accurately assessed due to the lack of statistical power.

References:

  1. Elshaboury RH, Hermsen ED, et. al.Chapter 84: Central Nervous System Infections. In: DiPiro JT, Talbert RL, Yee GC, Matzke GR, Wells BG, Posey L.  Pharmacotherapy: A Pathophysiologic Approach, 9eNew York, NY: McGraw-Hill; 2014. Available at: http://accesspharmacy.mhmedical.com/content.aspx?bookid=689&Sectionid=45310530. Accessed May 19, 2015.
  2. Meningococcal Vaccination. Centers for Disease Control and Prevention. Available at: http://www.cdc.gov/meningococcal/vaccine-info.html. Accessed 19 May 2015.
  3. Harrison LH, Shutt KA, et al. Meningococcal carriage among Georgia and Maryland high school students. J Infect Dis. 2015; 211 (11): 1,761 – 1,768.

 

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