*annual outbreak during dry season in meningitis belt
**dry winds make people's nose drier resulting in easy
why natural *wide range difference of nasopharynx carriage differs between countries?why ANZAC are the highest in the world outside meningitis belt**reason totally unknown**NZ & 3%**Nigeria boarding house 30-40%
==transmission==
*headache, neck stiffness, vomiting
*irritability and/or confusion
==vaccine==
===development history===
*1960s - purified PS vaccines for A and C
**immunity short term due to lack of T-cell involvement
*1990s - conjugated vaccines for A and C after success of Hib conjugate vaccine
*2000s - monovalent A vaccine for Africa
[[file:Development history of meningococcal vaccine.jpg]]