Meningococcal disease is caused by the meningococcus bacterium (Neisseria meningitidis), a Gram-negative endotoxin-producing organism.3 Meningococcus frequently causes serious and rapidly progressive disease and despite effective antimicrobial therapy and improvements in intensive care, the overall case fatality rate remains at 10%–15%. The most common clinical presentation is that of acute bacterial meningitis; other presentations include pneumonia, septic arthritis and meningococcaemia, which can occur with or without meningitis.3 Of the patients who survive meningococcal disease, 10%–20% develop permanent sequelae including gangrene, extensive skin scarring, cerebral infarction, neurosensory hearing loss, cognitive deficits or seizure disorders.3

Relevant vaccine history

2003

  • Meningococcal C conjugate vaccine added to childhood vaccination schedule at 12 months of age.

2003–2007

  • National meningococcal C catch-up vaccination program for all children 2–19 years of age.

Key points

Routine meningococcal C vaccination, implemented in 2003, has resulted in a substantial decrease in cases caused by serogroup C. However, rates of meningococcal disease remain higher in Aboriginal and Torres Strait Islander people than in other people. The predominant serogroup of N. meningitidis responsible for disease in both Aboriginal and Torres Strait Islander and other people is serogroup B, for which no vaccine is currently on the National Immunisation Program.

Top of page

Disease trends

Over the 10-year period from 2000 to 2010, there has been a substantial decline in notifications of serogroup C meningococcal disease in both Aboriginal and Torres Strait Islander and other people (Figure 2.6.1). Comparing pre-vaccine (2000–2002) and post-vaccine (2008–2010) periods, notification rates declined by 74% in Aboriginal and Torres Strait Islander people and by 92% in other people. However, even in the pre-vaccine period, notifications for serogroup B meningococcal disease, for which no vaccine is currently available, were substantially higher than for serogroup C in both Aboriginal and Torres Strait Islander and other people. Notification rates for serogroup B meningococcal disease declined over the same period, but to a lesser extent than serogroup C, and for reasons probably unrelated to vaccination. Serogroup B notifications decreased by 38% in Aboriginal and Torres Strait Islander people and by 36% in other people. Despite the overall downward trends, notification rates remain higher in Aboriginal and Torres Strait Islander people than in other people for both serogroups.

Figure 2.6.1: Meningococcal disease notification rates and 95% confidence intervals, selected Australian states,* 2000 to 2010, by Indigenous status and serogroup

Figure 2.6.1: is a line chart showing the Meningococcal disease notification rates and 95% confidence intervals, selected Australian states, 2000 to 2010. A link to a text description follows.

* Jurisdictions with satisfactory data quality over the whole time period; see Appendix A (New South Wales, Northern Territory, Queensland, South Australia, Victoria, Western Australia).

† Notifications where the date of diagnosis was between 1 January 2000 and 31 December 2010.

Text description of Figure 2.6.1 (TXT 1 KB)

Top of page

Serogroup data quality has improved over time. The serogroup was recorded for 933 (86%) of the 1,079 notifications in this reporting period, compared with 738 (58%) of 1,263 notifications in the previous period (2003–2006). The serogroup was identified in 92% of the cases in Aboriginal and Torres Strait Islander people and 88% of cases in other people. While serogroup B was relatively more common in Aboriginal and Torres Strait Islander than other people in the pre-vaccine period (73% of cases vs 59% of cases), there was little difference in serogroup B distribution in the most recent period (82% vs 86%).

Notification data are presented for all jurisdictions for the period 2007–2010. Hospitalisation data are presented for six jurisdictions (all except Tasmania and the Australian Capital Territory) by financial year for the period July 2005 to June 2010.

A total of 1,079 notifications and 2,230 hospitalisations for meningococcal disease were recorded during these reporting periods (Table 2.6.1 and Table 2.6.2). Of these, 104 (9.6%) notifications and 189 (8.5%) hospitalisations were reported in Aboriginal and Torres Strait Islander people, which were similar to the proportions (8% for both notifications and hospitalisations) in the previous reporting period (2003–2006).

Notification and hospitalisation rates generally decrease with increasing age in both Aboriginal and Torres Strait Islander and other people. However, rates in ‘other’ young adults are slightly higher than in older children (Table 2.6.1 and Table 2.6.2).

Table 2.6.1: Meningococcal disease notifications, all Australian states, 2007 to 2010, by age group and Indigenous status
Age group
(years)
Indigenous status Notifications* (2007–2010)
n Rate Rate ratio

* Notifications where the date of diagnosis was between 1 January 2007 and 31 December 2010.

† Average annual age-specific rate per 100,000 population.

‡ Includes cases with age unknown. Rates for all ages combined are age-standardised to the Australian Bureau of Statistics Australian population estimates for 2006.

§ Indicates statistically significant, 95% confidence intervals do not overlap 1.0.

0–4
Indigenous
62
23.2
3.8§
Other
322
6.1
5–14
Indigenous
21
4.1
4.1§
Other
105
1.0
15–24
Indigenous
8
1.8
0.8
Other
283
2.4
25–49
Indigenous
9
1.3
2.7§
Other
147
0.5
>50
Indigenous
4
1.5
3.4§
Other
118
0.4
All ages
Indigenous
104
3.2
2.7§
Other
975
1.2

Top of page

Table 2.6.2: Meningococcal disease hospitalisations, selected Australian states, 2005 to 2010, by age group and Indigenous status
Age group
(years)
Indigenous status Hospitalisations* (2005–2010)
n Rate Rate ratio

* Hospitalisations (New South Wales, Northern Territory, Queensland, South Australia, Victoria, Western Australia only) where the date of separation was between 1 July 2005 and 30 June 2010.

† Average annual age-specific rate per 100,000 population.

‡ Includes cases with age unknown. Rates for all ages combined are age-standardised to the Australian Bureau of Statistics Australian population estimates for 2006.

§ Indicates statistically significant, 95% confidence intervals do not overlap 1.0.

0–4
Indigenous
127
40.5
3.5§
Other
708
11.5
5–14
Indigenous
32
5.2
2.3§
Other
278
2.2
15–24
Indigenous
13
2.6
0.7
Other
494
3.6
25–49
Indigenous
15
1.9
2.1§
Other
316
0.9
>50
Indigenous
2
0.7
0.8
Other
245
0.8
All ages
Indigenous
189
4.5
2.2§
Other
2,041
2.1

Both notification and hospitalisation rates were higher in Aboriginal and Torres Strait Islander people than in other people across most age groups. However, in the 15–24 years age group, both the notification and hospitalisation rates were slightly higher in other people, although not statistically significantly so (Table 2.6.1 and Table 2.6.2). The highest rates were found in the 0–4 years age group. The overall Indigenous to non-Indigenous rate ratio was 2.7:1 for notifications and 2.2:1 for hospitalisations.

There were 42 deaths reported from the five jurisdictions (New South Wales, the Northern Territory, Queensland, South Australia and Western Australia) for the period 2006–2010 with meningococcal infection as the underlying cause and 45 deaths with meningococcal infection as either the underlying or a contributing cause. There were 1–4 deaths recorded with meningococcal infection as the underlying cause in Aboriginal and Torres Strait Islander people aged <5 years, 1–4 in those aged 5–49 years and none in those aged ≥50 years. The ABS provides ranges when absolute numbers of deaths are low.

Top of page

Comment

Routine meningococcal C vaccination for infants and the high-school catch-up program, implemented from 2003, have resulted in a significant decrease in cases associated with serogroup C. However, the predominant serogroup responsible for disease in both Aboriginal and Torres Strait Islander and other people remains serogroup B, for which no vaccine is available, and for which the disease burden is higher in Aboriginal and Torres Strait Islander people.

Neisseria meningitidis is carried harmlessly in the nose and throat of approximately 10% of the population, with transmission via prolonged close contact. Conjugate meningococcal vaccines reduce carriage of meningococci, which allows for significant indirect benefits of herd immunity and reduced transmission.47

Disease risk has also been demonstrated in different countries to vary among different portions of their population. In the United Kingdom, invasive meningococcal disease incidence and mortality have been found to be socially patterned, with the most deprived (20%) having twice the incidence rate than that of the most affluent quintile. In New Zealand, Maori and Pacific Islander people were found to have significantly higher rates of invasive meningococcal disease than the European population.48

A vaccine protecting against serogroup B disease, now licensed in Australia, could reduce the disparity between Aboriginal and Torres Strait Islander and other people and greatly reduce the overall meningococcal disease burden.