South Australian Meningococcal B Vaccine Herd Immunity Study

This cluster randomised controlled study will be conducted in the context of funded 4CMenB vaccine offered to all students in years 10, 11, and 12.

Year 10 and 11 students will undergo baseline and 12 months posterior pharyngeal swabs. Year 12 students will undergo baseline posterior pharyngeal swabs only.

Randomisation will take place at the school level and will be stratified by school size ((<60, 60 to 119, and ≥120 students per year level) and school socio-economic status (SES), as measured by the Index of Community Socio-Educational Advantage (ICSEA); (ICSEA <970, 970 to 1020, >1020) For the purposes of the study a school is defined as an educational institution at which students in years 10, 11, 12 physically attend school during the week. All 260 schools in metropolitan and rural SA will be approached to participate in the study. All schools agreeing to participate will be randomised to 4CMenB vaccine in 2017 or 2018. Students at schools randomised to receive the vaccine at baseline will receive the 4CMenB vaccine in 2017. Students at schools randomised to receive the vaccine at the 12 month posterior pharyngeal swab will receive the 4CMenB vaccine in 2018.

Primary Objectives

• Estimate the difference in carriage prevalence of disease causing genogroup of N. meningitidis (A, B, C, W, X, Y) following the 12 month pharyngeal swab in year 10 and 11 students who received two doses of Bexsero®, compared to unvaccinated students.

Secondary objectives

• Estimate the difference in carriage prevalence of each disease causing genogroup of N. meningitidis (A, B, C, W, X, Y) following the 12 month pharyngeal swab in year 10 and 11 students who received two doses of Bexsero®, compared to unvaccinated students.
• Estimate the difference in carriage prevalence of all genogroups of N. meningitidis following the 12 month pharyngeal swab in year 10 and 11 students who received two doses of Bexsero ®, compared to unvaccinated students.
• Estimate the difference in acquisition (negative at baseline, positive at 12 month followup) of carriage of disease causing genogroups of N. meningitidis (A, B, C, W, X, Y) over a 12 month period in students who received two doses of Bexsero ®, compared to unvaccinated students.
• Estimate the difference in acquisition (negative at baseline, positive at 12 month followup) of carriage of all genogroups of N. meningitidis over a 12 month period in students who received two doses of Bexsero ®, compared to unvaccinated students
• Identify characteristics associated with carriage prevalence of all genogroups N. meningitidis in South Australian school students at baseline and 12 months.
• Identify characteristics associated with carriage prevalence of disease causing genogroups of N. meningitidis (A, B, C, W, X, Y) in South Australian school students at baseline and 12 months.

Exploratory objectives

• Describe changes in invasive meningococcal rates (attack rates) across all age groups pre and post 4CMenB vaccine intervention in South Australia.
• Describe N. meningitidis carriage density in year 10, 11, and 12 students using qPCR at baseline and 12 months in both vaccinated and unvaccinated students.
• Describe genome sequencing of N. meningitidis disease causing (A, B, C, W, X, Y) sequence types in year 10, 11, and 12 students at baseline and at 12 months.
• In schools randomized to Group A, describe the association of carriage prevalence of disease causing genogroups and vaccine uptake at school level following implementation.
• In schools randomized to Group A, describe the association of carriage prevalence of all N. meningitidis and vaccine uptake at school level following implementation.

Inclusion criteria

• South Australian secondary school students in years 10, 11, and 12 in 2017
• Written parental consent for those under the age of 18
• Written student consent assent for those under the age of 18 (or if 18 years old and older consent for themselves)
• Available at school for at least the first pharyngeal swab and willing to comply with study procedures

Exclusion criteria

• Previous anaphylaxis following any component of Bexsero vaccine
• Previous receipt of meningococcal B vaccine (Bexsero)
• Known pregnancy