What is Bexsero?
Bexsero (MenB-4C) is a four-component meningococcal serogroup B vaccine licensed for active immunization to prevent invasive disease caused by Neisseria meningitidis serogroup B in individuals aged 10 through 25 years. 1
Vaccine Composition
Bexsero contains four distinct antigenic components designed to provide broad coverage against diverse serogroup B meningococcal strains 1:
Three recombinant surface proteins (50 mcg each):
- Neisserial adhesin A (NadA)
- Neisserial Heparin Binding Antigen (NHBA)
- Factor H binding protein (fHbp)
Outer Membrane Vesicles (OMV) (25 mcg) expressing PorA serosubtype P1.4
Adjuvant: 1.5 mg aluminum hydroxide
Other components: Sodium chloride, histidine, and sucrose
All recombinant proteins are produced in Escherichia coli and purified through column chromatography, then adsorbed onto aluminum hydroxide 1.
Dosing Schedules
The dosing has been updated as of October 2024 to align with the other licensed MenB vaccine (Trumenba) 2:
For persons aged ≥10 years at increased risk (Category A recommendation):
- 3-dose series: 0,1-2, and 6 months 3, 2
- This schedule provides earlier protection and maximizes short-term immunogenicity
For healthy adolescents and young adults aged 16-23 years (Category B recommendation, based on shared clinical decision-making):
- 2-dose series: 0 and 6 months 3, 2
- Note: The interval was extended from the previous ≥1 month to 6 months based on new immunogenicity data
Critical point: The two MenB vaccines (Bexsero and Trumenba) are not interchangeable—the same product must be used for all doses in a series 3.
Who Should Receive Bexsero?
Category A (routine recommendation) - Persons aged ≥10 years at increased risk 3, 4:
- Complement component deficiencies (C3, C5-C9, properdin, factor D, or factor H)
- Persons receiving eculizumab (Soliris)
- Functional or anatomic asplenia, including sickle cell disease
- Microbiologists routinely working with N. meningitidis
- Persons at risk during serogroup B meningococcal disease outbreaks
Category B (may be considered based on shared clinical decision-making) - Healthy adolescents and young adults aged 16-23 years (preferred ages 16-18 years) 3, 4:
- Not at increased risk but may benefit from short-term protection
- This is not a routine recommendation but rather an individual decision
Safety Profile
Bexsero has demonstrated an acceptable safety profile across extensive clinical trials and post-marketing surveillance 5, 6:
Common adverse reactions (generally mild to moderate):
- Injection site pain: ≥85% of subjects
- Fatigue: ≥40%
- Headache: ≥35%
- Myalgia: ≥30%
- Fever: ~50% in infants, less common in adolescents
- Chills: ≥15%
Post-marketing surveillance findings 5:
- Analysis of 1,867 VAERS reports (representing 332 reports per million doses distributed) found 96% were non-serious
- Most common reported events: injection site pain (22%), pyrexia (16%), headache (16%)
- Data mining identified disproportionate reporting for "injected limb mobility decreased" secondary to extensive swelling and injection site pain
- No new safety concerns identified
Important caveat: While Kawasaki syndrome cases have been reported, surveillance data have not shown frequencies significantly different from non-vaccinated individuals 7, 8.
Vaccine Effectiveness
Real-world effectiveness data from Spain (2015-2019) demonstrated 9:
- Complete vaccination (≥2 doses per manufacturer recommendations): 76% effective (95% CI: 57-87%) against invasive meningococcal disease caused by any serogroup
- 71% effective (95% CI: 45-85%) specifically against serogroup B disease
- Partial vaccination (incomplete series): 54% effective (95% CI: 18-74%)
The vaccine is conservatively estimated to provide 66-91% coverage against meningococcal serogroup B strains worldwide 7.