“Meningococcal disease generally occurs 1–10 days after exposure and presents as meningitis in approximately 50% of cases in the United States. Meningococcal meningitis is characterized by sudden onset of headache, fever, and neck stiffness, sometimes accompanied by nausea, vomiting, photophobia, or altered mental status. Approximately 30% of people with meningococcal disease present with meningococcal sepsis, known as meningococcemia.

Meningococcemia often involves hypotension, acute adrenal hemorrhage, and multiorgan failure. An additional 15% of meningococcal disease cases in the United States, primarily among adults >65 years of age, present as bacteremic pneumonia.

Other presentations (e.g., septic arthritis) also occur. Among infants and children aged <2 years, meningococcal disease can have non-specific symptoms. Neck stiffness, usually seen in people with meningitis, might be absent in this age group.

Meningococcal disease progresses rapidly and has a case-fatality rate of 10–15%, even with antimicrobial drug treatment. Without rapid treatment, fatality rates can be much higher.”

Center for Disease Control and Prevention – CDC (Meningococcal Disease | Yellow Book | CDC)