Four vaccine preventable diseases that are rare in Australia are considered together in this chapter – diphtheria, tetanus, poliomyelitis and rubella. The following data are presented for these diseases: notification data for all jurisdictions for the period 2007–2010 (Table 2.12.1); hospitalisation data for six jurisdictions (all except Tasmania and the Australian Capital Territory) by financial year for the period July 2005 to June 2010 (Table 2.12.2); and death data for New South Wales, the Northern Territory, Queensland, South Australia and Western Australia for the period 2006–2010. Please refer to the 2010 report Vaccine preventable diseases in Australia, 2005 to 2007 for more detailed information on these diseases.24

Relevant vaccine history

Diphtheria and tetanus

No difference in vaccination programs between Aboriginal and Torres Strait Islander and other people.

1932

  • School-based diphtheria vaccination programs commenced.

1975

  • First national vaccination schedule recommended and funded 4 DTPw* doses for infants at 3, 4, 5 and 18 months of age; booster doses of tetanus toxoid recommended every 5 years.

1978

  • Fourth dose removed from schedule (reinstated 1985).

1982

  • Booster doses of tetanus toxoid recommended every 10 years.

1994

  • Fifth dose added at 4–5 years of age.

1999

  • DTPa recommended and funded for all 5 childhood DTP doses.

2003

  • 18-month booster replaced by adolescent dose; the eligible age group varied in different jurisdictions.

2008–2012

  • dTpa funded temporarily by various states and territories for parents/contacts of infants under cocoon strategy during pertussis epidemic. Program timing and eligibility criteria differed between jurisdictions.

Current schedule

DTPa at 2, 4, 6 months and 4 years of age, dTpa at 10–17 years of age.

* DTPw: diphtheria, tetanus and pertussis (whole-cell)

† DTPa: diphtheria, tetanus and pertussis (acellular)

‡ dTpa: diphtheria, tetanus and pertussis (acellular), reduced antigen content

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Table 2.12.1: Notifications for diphtheria, tetanus, poliomyelitis and rubella, all Australian states, 2007 to 2010, by age group and Indigenous status
Age group
(years)
Indigenous status Diphtheria Tetanus Poliomyelitis Rubella
n Rate* n Rate* n Rate* n Rate*

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

0–4
Indigenous
0
0.0
0
0.0
0
0.0
0
0.0
Other
0
0.0
0
0.0
0
0.0
12
0.2
5–14
Indigenous
0
0.0
0
0.0
0
0.0
0
0.0
Other
0
0.0
0
0.0
0
0.0
6
0.1
15–24
Indigenous
0
0.0
0
0.0
0
0.0
0
0.0
Other
0
0.0
0
0.0
1
<0.01
31
0.3
25–49
Indigenous
0
0.0
0
0.0
0
0.0
0
0.0
Other
0
0.0
1
<0.01
0
0.0
86
0.3
>50
Indigenous
0
0.0
0
0.0
0
0.0
0
0.0
Other
0
0.0
11
0.04
0
0.0
8
0.03
All ages
Indigenous
0
0.0
0
0.0
0
0.0
0
0.0
Other
0
0.0
12
0.01
1
<0.01
143
0.2

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Table 2.12.2: Hospitalisations for diphtheria, tetanus, poliomyelitis and rubella, selected Australian states,* 2005 to 2010, by age group and Indigenous status
Age group
(years)
Indigenous status Diphtheria Tetanus Poliomyelitis Rubella
n Rate n Rate n Rate n Rate

* New South Wales, the Northern Territory, Queensland, South Australia, Victoria, Western Australia.

† Hospitalisations where the date of separation was between 1 July 2005 and 30 June 2010.

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

0–4
Indigenous
7
2.2
1
0.3
0
0.0
2
0.6
Other
2
0.03
0
0.0
0
0.0
16
0.3
5–14
Indigenous
6
1.0
0
0.0
0
0.0
1
0.2
Other
3
0.02
1
0.01
0
0.0
7
0.1
15–24
Indigenous
3
0.6
0
0.0
1
0.2
0
0.0
Other
1
0.01
5
0.04
1
0.02
17
0.1
25–49
Indigenous
27
3.4
1
0.1
0
0.0
3
0.4
Other
14
0.04
22
0.1
1
0.01
66
0.2
>50
Indigenous
4
1.3
0
0.0
0
0.0
0
0.0
Other
35
0.1
57
0.2
20
0.1
28
0.1
All ages
Indigenous
47
1.9
2
0.08
1
0.04
6
0.2
Other
55
0.1
85
0.09
22
0.06
134
0.1

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Diphtheria

Diphtheria is a severe upper respiratory illness caused by Corynebacterium diphtheriae, a Gram-positive bacterium. The major threat of diphtheria is fatal acute respiratory obstruction. Diphtheria skin infections can also occur in skin lesions in warm climates and under conditions of poor hygiene.3 The severe symptoms of diphtheria are associated with toxin produced by the organism. Non-toxigenic forms can cause mild respiratory and skin infections.

There were no notifications and a total of 102 hospitalisations recorded in this reporting period. Notifications are regarded as the most reliable source of data on toxigenic diphtheria, as public health follow-up and laboratory confirmation is routine. Of the total hospitalisations, 47 (46%) were reported in Aboriginal and Torres Strait Islander people with higher rates than other people in all age groups. The highest rate was among Aboriginal and Torres Strait Islander people aged 25–49 years (3.4 per 100,000), with an Indigenous to non-Indigenous rate ratio of 89:1. In the absence of any notifications during this period, the hospitalisations are most likely to have been due to non-toxigenic or culture-negative suspected diphtheria cases or coding errors.

There were 1–4 deaths reported from the five jurisdictions (New South Wales, the Northern Territory, Queensland, South Australia and Western Australia) for the period 2006–2010 with diphtheria as either the underlying or a contributing cause of death, none of which were reported in Aboriginal and Torres Strait Islander people. At least 1 death recorded as due to diphtheria in 2006 has been previously investigated and reported as likely to be a coding error;24 hence the data need to be interpreted with caution.

Diphtheria has become rare in Australia but sporadic cases do occur occasionally in unvaccinated individuals. Historical reports document that cutaneous toxigenic C. diphtheriae was endemic in the Central Australian desert region and the tropical north of Australia as late as the 1990s, while diphtheria had become a rare occurrence in other states of Australia since the introduction of the diphtheria-tetanus-pertussis vaccine in the 1950s.107

A case of cutaneous toxigenic diphtheria acquired in East Timor and notified in 2001 was the first Australian case notified since 1993.24 Since then 4 cases have been reported, all in 2011 (not included in this reporting period); this included a cluster of 3 cases, one of them fatal respiratory diphtheria, in an unvaccinated family, where contact with a returned traveller was the suspected source of infection.108 This reinforces the importance of primary vaccination, and also booster doses to prevent travel-associated C. diphtheriae infection. Non-toxigenic skin infections still occur, largely limited to Aboriginal and Torres Strait Islander people in the Northern Territory. These infections are not vaccine preventable and underline the importance of improvements to hygiene in remote communities.

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Tetanus

Tetanus is unique among vaccine preventable diseases in that it is not communicable.3 It is caused by Clostridium tetani a Gram-positive, spore-forming, anaerobic bacterium that grows at the site of injury and produces toxin with local and systemic neuromuscular effects.3

A total of 12 notifications and 87 hospitalisations (with tetanus as either the primary or a contributing cause) were recorded during this reporting period; of these 0 notifications and 2 hospitalisations were reported in Aboriginal and Torres Strait Islander people. One of the hospitalisations occurred in a young child and the other was in a young adult. Tetanus was recorded as the primary cause in 55 hospitalisations; none were among Aboriginal and Torres Strait Islander people. No deaths were reported in Aboriginal and Torres Strait Islander people, and there were 1–4 deaths in other people (the ABS provides ranges when absolute numbers of deaths are low).

Tetanus is a rare disease in Australia, although the exact number of cases is difficult to estimate. Tetanus is likely to be under-notified, as with many clinically diagnosed diseases, while hospitalisations may contain inter-hospital transfers for the same incident, and coding errors. Tetanus predominantly occurs among the adult population who are likely to be unimmunised or insufficiently immunised. A booster dose of a tetanus- and diphtheria-containing vaccine is recommended for adults who are ≥50years of age and have not received a tetanus-containing vaccine in the previous 10 years.26 It is thought that the booster dose is poorly utilised in Australia.24 Strategies to improve uptake in this age group should be investigated.

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Poliomyelitis

Poliovirus infection involves the gastrointestinal tract and may progress to the central nervous system. Poliovirus exposure in a person susceptible to poliomyelitis results in one of the following consequences: asymptomatic infection, minor illness, non-paralytic poliomyelitis (aseptic meningitis) or paralytic poliomyelitis. Post-polio syndrome, which encompasses the late manifestations of acute paralytic polio, occurs in 25%–40% of paralytic cases. In recent years, because the feasibility of polio eradication has been demonstrated, the disease has gained renewed attention.3

Relevant vaccine history

Poliomyelitis

No difference in vaccination programs between Aboriginal and Torres Strait Islander and other people.

1956

  • IPV* programs commenced in individual jurisdictions.

1966

  • IPV replaced by OPV.

1975

  • First national vaccination schedule recommended and funded for infants aged 6, 8 and 10 months.

2005

  • IPV funded to replace OPV for children in combination vaccine formulations.

Current schedule

IPV given at 2, 4, 6 months and 4 years of age in combination vaccines.

* IPV: inactivated poliomyelitis vaccine

† OPV: live attenuated oral poliomyelitis vaccine

During this reporting period there was 1 notification of polio; the case was in a non-Indigenous person. This case occurred in 2007 and was due to wild poliovirus being acquired by an Australian resident while visiting relatives in Pakistan.109 This individual had received oral polio vaccine during childhood.

A total of 23 hospitalisations were recorded, of which 1 was in an Aboriginal and Torres Strait Islander person. Notifications are individually reviewed by an expert panel, and are therefore regarded as a more reliable indicator of true polio disease than hospitalisations. The disparity between notification and hospitalisation might be explained by the occurrence of post-polio syndrome rather than acute cases, since the majority of those hospitalisations occurred in those ≥50 years of age. They may also represent cases of acute flaccid paralysis where polio could not be excluded. No deaths were recorded with poliomyelitis as the underlying cause. Poliomyelitis was recorded as a contributing cause in 11 deaths, none of which occurred in those identifying as Aboriginal and Torres Strait Islander people. This might again indicate people with post-polio syndrome.

Australia was declared polio free in August 2000, indicating the absence of circulation of wild poliovirus.110 However, a major obstacle to polio eradication appears to be through international spread via travellers, whether they are refugees, pilgrims, traders or tourists.111 Until the disease has been eradicated there is still a risk of acquiring polio and of re-introduction into polio-free areas.111

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Rubella

Rubella is caused by the rubella virus. The most common symptoms of rash and lymphadenopathy are usually transient and benign, but infection may be asymptomatic. The severity of the disease increases with age,112 as does the risk of complications such as thrombocytopenia, encephalitis and a late syndrome of progressive rubella panencephalitis. Rubella is of particular importance when acquired in the first trimester of pregnancy because it is associated with spontaneous abortion or in surviving babies with abnormalities of congenital rubella syndrome (CRS) including cataracts, retinopathy, deafness, heart defects and neurological deficit.3

Relevant vaccine history

Rubella

1971

  • Rubella vaccine funded for females aged 12–14 years (school-based program) and for susceptible women prior to pregnancy.

1989

  • MMR* vaccine recommended and funded on the national schedule at 12 months of age (9 months for Aboriginal and Torres Strait Islander infants in the Northern Territory).

1996

  • MMR funded as second dose of rubella-containing vaccine for all adolescents.

1998

  • Recommended age for first dose of MMR vaccine for Aboriginal and Torres Strait Islander children in the Northern Territory increased from 9 months to 12 months of age.
  • Recommended age for second dose of MMR vaccine lowered to 4–5 years.

2013

  • Second dose moved forward to 18 months of age, given as MMRV.

* MMR: measles, mumps and rubella

† MMRV: measles, mumps, rubella and varicella

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A total of 143 notifications, 140 hospitalisations and no deaths were recorded during the current reporting periods; of these, 0 notifications and 6 hospitalisations were reported in Aboriginal and Torres Strait Islander people. Two of these hospitalisations occurred in children <4 years of age. There were 23 cases in which rubella was recorded as the primary cause of hospitalisation; none of these were in Aboriginal and Torres Strait Islander people. There were 2 notifications of CRS but none in Aboriginal and Torres Strait Islander infants.

Australian seropositivity, vaccine coverage and notification data all support the hypothesis that endemic transmission of rubella may have been eliminated in Australia.112 However, sporadic cases continue to occur, although the absolute number is difficult to estimate. Notified cases may underestimate total cases as they require laboratory confirmation. The level of laboratory confirmation of hospitalisations is not known, and they may include people diagnosed with rubella but hospitalised for another primary cause. Only 1 case of CRS was notified to the Australian Paediatric Surveillance Unit during this reporting period, in the infant of a woman born overseas.113 Cases of rubella and CRS related to overseas travel are likely to continue to occur in Australia while transmission continues in other countries. Women born in countries with low vaccination coverage have been identified as the highest priority for rubella screening and vaccination if non-pregnant or post-partum vaccination if pregnant. Aboriginal and Torres Strait Islander women from some remote communities have been identified as having lower levels of rubella immunity than other women,114 underlining the importance of screening and vaccination in this group.

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Comment

These four diseases have been well controlled in Australia, and none are of particular concern in Aboriginal and Torres Strait Islander people. This underlines the substantial health benefits to Aboriginal and Torres Strait Islander and other Australians from effective vaccines in a national vaccination program. However, all of these diseases are still endemic in many developing countries around the world, and could be easily acquired by travellers or imported by returning travellers, posing a threat to unimmunised individuals in Australia.108,109 Maintaining high vaccination coverage and timely vaccination among children and adults as recommended should remain an important goal for achieving and sustaining elimination of these diseases.