Prevention

Why?

• A third of family members of a patient with meningococcal disease were carrying N. meningitidis (34%; 95% CI: 23% to 46%). ^c
• Carriage is more likely in family members with upper respiratory tract symptoms. ^c

Antibiotic prophylaxis reduces secondary cases of meningococcal meningitis

Patient	Treatment	Comparison	Outcome	CER	RRR (95% CI)	NNT (95% CI)
soldiers at risk of meningococcal meningitis a	2 days of sulfadiazine	nothing	meningococcal meningitis at 8 weeks	0.21%	94% (74% to 98%)	500 (370 to 760)

Upper respiratory tract symptoms make carriage of N. meningitidis less likely

Patient	Target Disorder and Reference Standard	Diagnostic Test	LR+ (95% CI)	Post-test Probability	LR- (95% CI)	Post-test Probability
family member of patient with meningococcal disease c (pre-test probability: 34%)	carriage of Neisseria meningitidis ( culture of nasopharyngeal and tonsillar swabs)	upper respiratory tract symptoms	2.4 (1.5 to 3.8)	61%	0.26 (0.10 to 0.65)	14%