Meningococcal disease is caused by the bacterium Neisseria meningitidis. The bacterium is commonly known as meningococcus.
There are 13 known meningococcal serogroups, distinguished by differences in surface polysaccharides of the bacterium’s outer membrane capsule. Globally, serogroups A, B, C, W and Y most commonly cause disease.
Invasive meningococcal disease (IMD) is a rare but serious disease. It most commonly presents as septicaemia and/or meningitis.
Meningococcal vaccines are recommended for:
- infants, children, adolescents and young adults
- special risk groups, including Aboriginal and Torres Strait Islander people, individuals with certain medical conditions (see List. Specified medical conditions associated with increased risk of invasive meningococcal disease), laboratory workers who frequently handle Neisseria meningitidis, travellers, and young adults who live in close quarters or who are current smokers
Several vaccines are available in Australia to reduce the risk of meningococcal disease. However, no single vaccine protects against all serogroups:
- 2 vaccines protect against meningococcal serogroup B — MenB vaccines.
- 2 vaccines protect against meningococcal serogroup C only — MenC vaccine and Hib-MenC vaccine (combined with Haemophilus influenzae type b).
- 3 vaccines protect against meningococcal serogroups A, C, W and Y — MenACWY (quadrivalent) conjugate vaccines.
Although it is rare, IMD is a serious infection that can cause significant illness, disability and death. Vaccination programs have successfully reduced the incidence of IMD caused by serogroup C. The incidence of IMD caused by serogroups W and Y increased from 2013 and 2015, respectively.
However, the incidence of meningococcal W disease has fallen since state vaccination programs with MenACWY vaccine were introduced in 2017 and subsequently incorporated into the National Immunisation Program. IMD caused by serogroup B continues to occur in Australia.