Results - Part 2

Bloodborne diseases

In 2014, the bloodborne diseases reported to the NNDSS were hepatitis B, C, and D infections. Both hepatitis B and C infections were notified to the NNDSS as either ‘newly acquired’, where evidence was available that the infection was acquired in the 24 months prior to diagnosis; or ‘greater than 2 years or unspecified’ period of infection. These categories were reported from all states and territories except Queensland where all cases of hepatitis C infection, including newly acquired, were reported as being ‘greater than 2 years or unspecified’.¹⁹ Determination of a case as ‘newly acquired’ is reliant on public health follow-up, with the method and intensity of follow-up varying by jurisdiction and over time.

In interpreting these data it is important to note that changes in notified cases over time may not solely reflect changes in disease prevalence or incidence. National testing policies developed by the Australian Society for HIV Medicine and screening programs, including the preferential testing of high risk populations such as prisoners, injecting drug users and persons from countries with a high prevalence of hepatitis B or C infection, may contribute to these changes.^20,21

Information on exposure factors relating to the most likely source(s) of or risk factors for infection for hepatitis B and C were reported in a subset of newly acquired infections. The collection of enhanced data is also dependent on the level of public health follow-up, which is variable by jurisdiction and over time.

Notifications of HIV diagnoses were reported directly to the Kirby Institute, which maintains the National HIV Registry. Information on national HIV surveillance can be obtained from the Kirby Institute web site (http://www.kirby.unsw.edu.au/).

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Hepatitis B

Hepatitis B is a potentially life-threatening liver infection caused by the hepatitis B virus. Major modes of transmission include unprotected sexual contact or needle sharing with an infected person, and perinatal transmission from mother to child. Symptoms of acute infection include abdominal pain, nausea and vomiting progressing to jaundice. Outcomes vary inversely with age; infected infants are more likely to progress to chronic infection whereas people who are infected as adults often clear the virus. Chronic infection can lead to a number of liver complications including cirrhosis, cancer and liver failure.²²

Hepatitis B notifications are classified as being either ‘newly acquired’ (evidence that infection was acquired within the 24 months prior to diagnosis) or ‘unspecified’ (infection acquired more than 24 months prior to diagnosis or not able to be specified).

Epidemiological situation in 2014

In 2014, there were 6,670 notified cases of hepatitis B (both newly acquired and unspecified), representing a rate of 28.4 cases per 100,000 (Figure 4).

Figure 4: Notification rate for newly acquired hepatitis B and unspecified hepatitis B, Australia, 2005 to 2014, by year

Text version of Figure 4 (TXT 1 KB)

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Between 2005 and 2014, rates of newly acquired hepatitis B decreased by 40% from 1.3 to 0.7 per 100,000 (Figure 4). The decline in newly acquired hepatitis B notifications may be attributed to the hepatitis B vaccination program, which was introduced nationally for infants in 2000, and nationally funded adolescent hepatitis B vaccination programs, which were introduced from 1997 onwards, depending on the jurisdiction.²³ As at 30 June 2014, approximately 92% of children 12–15 months of age in Australia were assessed as being fully immunised for hepatitis B.²⁴ A 2007 study showed significant improvements in immunity to hepatitis B for the 12–17 years age group in jurisdictions with established school-based programs compared to those jurisdictions without such programs.²⁵

From the 1980s, hepatitis B vaccination was also recommended for certain at-risk adults in Australia.²⁶ Some jurisdictions implemented vaccination programs to target identified at-risk adults in a variety of settings and at various times.²⁷ The full impact of Australian vaccination programs should be reflected in trends in chronic infection and reductions in hepatitis B related complications in the near future.²⁸

Between 2005 and 2014, rates of unspecified hepatitis B have declined slightly by 7% from 29.8 to 27.7 per 100,000. It is important to note the significant impact of immigration on rates for unspecified hepatitis B. In 2014, Western Australia reported a decline in asylum seeker boat arrivals coinciding with a decline in unspecified hepatitis B notifications in the state, particularly in the Kimberley region (which includes the postcode for Christmas Island). In 2011, an Australian study estimated that more than 95% of new cases of chronic hepatitis B virus infection entered the population through migration.²⁹

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Newly acquired hepatitis B

Epidemiological situation in 2014

In 2014, 176 cases of newly acquired hepatitis B infection were notified to the NNDSS, a rate of 0.7 per 100,000, which is similar to the 175 cases (0.8 per 100,000) reported in 2013 (Figure 4).

Geographical distribution

The highest rates were reported from the Northern Territory (1.2 per 100,000) and Queensland (1.1 per 100,000) (Table 5). This may be due to population differences between the jurisdictions, with hepatitis B disproportionately affecting a number of marginalised groups in Australia including migrant communities with origins in Asia, the Pacific and Africa; and Aboriginal and Torres Strait Islander people.^29–31

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Age and sex distribution

In 2014, males accounted for 77% of newly acquired hepatitis B notifications. In 2014, the highest rate of newly acquired hepatitis B infection was observed among males aged 35–39 years (2.7 per 100,000). For females, the highest rate was in those aged 40–44 years (1.1 per 100,000) (Figure 5). Exposure to hepatitis B may be more common in certain high risk groups, including immigrants from endemic regions; injecting drug users; prisoners; Aboriginal and Torres Strait Islander peoples; and men who have sex with men.^22,29 The greater representation of males in some of these groups may contribute to the higher notification rates among males.

Figure 5: Notification rate for newly acquired hepatitis B, Australia, 2014, by age group and sex

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Between 2005 and 2014, most age group specific notification rates were low and remained stable or trended downwards. The most marked decreases occurred among those aged 15–39 years. During this period, notification rates declined by 74% for those aged 15–19 years (from 0.8 to 0.2 per 100,000), by 71% for those aged 20–29 years (from 3.3 to 1.0 per 100,000) and by 38% for those aged 30–39 years (from 2.6 to 1.6 per 100,000) (Figure 6). These declines are likely to be attributable to the hepatitis B vaccination program.²⁷

Figure 6: Notification rate for newly acquired hepatitis B, Australia, 2005 to 2014, by year and selected age groups

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Risk groups

Enhanced data on risk factors and country of birth were provided by the Australian Capital Territory, New South Wales, South Australia, Tasmania, Victoria and Western Australia (Table 10). In 2014, 98 of 106 cases (92%) from these jurisdictions had at least 1 risk factor recorded, with a potential source of exposure not recorded or unable to be determined for the remainder. Sexual exposure was the most frequently reported potential source of infection (56/106, 53%), followed by injecting drug use (36/106, 34%). Of the 118 cases for which country of birth was reported, 91 were in Australian born persons (77%) and 27 cases were born overseas (10 from Asia, 8 from Europe, 4 from the Middle East, 4 from the Pacific, and 1 from South America).

Table 10: Enhanced risk factor data on notifications of newly acquired hepatitis B cases in selected jurisdictions,* 2014, by sex and risk factors^†‡

Exposure category	Number of exposure factors reported			Percentage of total cases* (n=106)
	Male	Female	Total
* Cases from the Australian Capital Territory, New South Wales, South Australia, Tasmania, Victoria and Western Australia. While these 6 jurisdictions provided enhanced data on risk factors, not all cases had this information recorded. † More than 1 exposure category for each case could be recorded. ‡ Analysis and categorisation of these exposures are subject to interpretation and may vary between reports. § The denominator used to calculate the percentage is based on the cases with recorded enhanced data from the Australian Capital Territory, New South Wales, South Australia, Tasmania, Victoria and Western Australia. As more than 1 exposure category for each notification could be recorded, the total percentage does not equate to 100%.
Sexual exposure	45	11	56	53
Sexual contact (hepatitis B partner status unknown) – opposite sex	16	6	22	21
Sexual contact (hepatitis B positive partner) – opposite sex	6	4	10	9
Sexual contact – not further classified	9	1	10	9
Sexual contact (hepatitis B partner status unknown) – same sex	10	0	10	9
Sexual contact (hepatitis B positive partner) – same sex	4	0	4	4
Injecting drug use	26	10	36	34
Skin penetration procedure	5	2	7	7
Tattoos	4	1	5	5
Ear or body piercing	0	1	1	1
Acupuncture	1	0	1	1
Undetermined	3	3	6	6
Imprisonment	5	0	5	5
Healthcare exposure	3	0	3	3
Major dental surgery work	2	0	2	2
Surgical work	1	0	1	1
Other	11	7	18	17
Other risk not elsewhere classified (≤24 months prior to diagnosis)	9	3	12	11
Non-IDU remote risk (>24 months prior to diagnosis)	1	2	3	3
Needlestick/biohazardous injury	1	1	2	2
Household contact	0	1	1	1
Unknown (not recorded)	2	0	2
Total exposure factors reported	98	33	131
Total number of cases	80	26	106

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Unspecified hepatitis B

Epidemiological situation in 2014

In 2014, 6,494 cases of unspecified hepatitis B infection were notified to the NNDSS, representing a rate of 27.7 per 100,000, compared with 6,940 cases (30.0 per 100,000) reported in 2013 (Figure 4).

Geographical distribution

In 2014, the Northern Territory had the highest rate of unspecified hepatitis B infection (61.3 per 100,000) (Table 5).

Age and sex distribution

In 2014, males accounted for 53% (3,451/6,494) of unspecified hepatitis B notifications, with an overall rate of 29.5 per 100,000 for males and 25.5 per 100,000 for females. Notification rates were similar for males and females in most age groups. Notification rates in both males and females peaked in the 30–34 years age group (Figure 7).

Figure 7: Notification rate for unspecified hepatitis B, Australia, 2014, by age group and sex*

* Excludes 36 cases where age and/or sex were not reported.

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Between 2005 and 2014, notification rates for unspecified hepatitis B decreased overall in the age groups less than 30 years of age but slightly increased in those aged 30–39 years and remained relatively stable in those aged 40 years or over (Figure 8). The decrease in rates for the younger age groups is likely explained by the introduction of the infant and adolescent hepatitis B vaccination programs.²⁶ The adolescent vaccination program commenced in some jurisdictions from 1997 and the infant vaccination program commenced nationally from 2000.³²

Figure 8: Notification rate for unspecified hepatitis B, Australia, 2005 and 2014, by year and selected age groups*

* Excludes 15 cases where age was not reported.

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Hepatitis C

Infection with hepatitis C virus causes inflammation of the liver. In more than 90% of cases, initial infection with hepatitis C virus is asymptomatic or mildly symptomatic. Approximately 50%–80% of cases go on to develop a chronic infection. Of those who develop a chronic infection, half will eventually develop cirrhosis or cancer of the liver.²² There is no vaccine to prevent hepatitis C infection.

Hepatitis C notifications are classified as being either ‘newly acquired’ (evidence that infection was acquired within the 24 months prior to diagnosis) or ‘unspecified’ (infection acquired more than 24 months prior to diagnosis or not able to be specified).

Epidemiological situation in 2014

Of the 10,682 cases of hepatitis C notified in 2014, 4% (433/10,682) were identified as having been newly acquired infections. The proportion of hepatitis C notifications identified as newly acquired has remained reasonably stable since 2005 (range: 3%–5%).

Between 2005 and 2014, hepatitis C notifications (both newly acquired and unspecified) declined by 12% from 12,135 to 10,682. This was mainly due to a downward trend in unspecified hepatitis C notifications, while newly acquired hepatitis C notifications remained low and relatively stable (Figure 9).

Figure 9: Notification rate for hepatitis C (newly acquired* and unspecified†) infection, Australia, 2005 to 2014, by year

* Data from all states and territories except Queensland.

† Data provided from Queensland includes both newly acquired and unspecified hepatitis C cases.

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Newly acquired hepatitis C

Epidemiological situation in 2014

Cases of newly acquired hepatitis C infection were reported from all states and territories except Queensland, where all cases of hepatitis C infection are reported as unspecified. Nationally, the notification rate in 2014 was 2.3 per 100,000 (n=433) compared with 2.2 per 100,000 (n=398) in 2013 (Figure 9).

Geographical distribution

In 2014, Western Australia reported the highest jurisdiction-specific rate of newly acquired hepatitis C infection (6.3 per 100,000) (Table 5).

Age and sex distribution

In 2014, males accounted for 70% (304/433) of newly acquired hepatitis C notifications. In 2014, the highest notification rate for newly acquired hepatitis C infection was observed among males aged 20–24 years (12.2 per 100,000). For females, the highest notification rate was in those aged 20–24 years (5.0 per 100,000) (Figure 10).

Figure 10: Notification rate for newly acquired hepatitis C* infection, Australia, 2014, by age group and sex

* Data from all states and territories except Queensland.

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Between 2005 and 2014, notification rates for newly acquired hepatitis C infection have declined overall among those in the 15–39 years age groups. The largest decrease from 2005 to 2014 occurred in the 15–19 years age groups (from 3.9 to 2.1 per 100,000) (Figure 11). This may be partly explained by the findings of a recent survey, which suggested a decrease in the prevalence of injecting drug use among young people in Australia.³³

Figure 11: Notification rate for newly acquired hepatitis C* infection, Australia, 2005 to 2014, by year and selected age groups^†

* Data from all states and territories except Queensland.

† Excludes 1 case where age was not reported (2005).

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Risk groups

Exposure histories for newly acquired hepatitis C cases reported in 2014 were analysed for all jurisdictions except Queensland (Table 11). In 2014, 99% (343/347) of cases with enhanced data had at least 1 risk factor recorded, with the potential source of exposure not recorded or unable to be determined for the remainder. Of the cases for which exposure history was reported, approximately 80% (279/347) had a history of injecting drug use and approximately 17% (59/347) reported possible sexual exposure.

Table 11: Enhanced risk factor data on notifications of newly acquired hepatitis C infection in selected jurisdictions,* 2014, by sex and risk factors^†‡

Exposure category	Number of exposure factors reported			Percentage of total cases§ (n=347)
	Male	Female	Total
* Includes data from all states and territories except Queensland (not notified). While the 7 jurisdictions provided enhanced data on risk factors, not all cases had this information recorded. † More than 1 exposure category for each notification could be recorded. ‡ Analysis and categorisation of these exposures are subject to interpretation and may vary between reports. § The denominator used to calculate the percentage is based on the total number of notified cases with recorded enhanced data, from all jurisdictions except Queensland (notified as unspecified hepatitis C). As more than 1 exposure category for each case could be recorded, the total percentage does not equate to 100%.
Injecting drug use	190	89	279	80
Imprisonment	77	9	86	25
Sexual contact	41	18	59	17
Sexual contact (hepatitis B positive partner) – opposite sex	19	17	36	10
Sexual contact (hepatitis B partner status unknown)	15	1	16	5
Sexual contact (hepatitis B positive partner) – same sex	7	0	7	2
Perinatal transmission	27	14	41	12
Other	21	15	36	11
Household contact	6	8	14	4
Other risk not elsewhere classified (≤24 months prior to diagnosis)	14	6	20	6
Needlestick/bio-hazardous injury	1	1	2	1
Skin penetration procedure	26	9	35	10
Tattoos	14	4	18	5
Ear or body piercing	5	4	9	3
Acupuncture	7	1	8	2
Healthcare exposure	7	3	10	3
Haemodialysis	4	2	6	2
Surgical work	2	1	3	1
Major dental surgery work	1	0	1	<1
Undetermined	3	6	9	3
Unknown (not recorded)	1	0	1
Total exposure factors reported	389	157	546
Total number of cases	233	114	347

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Approximately 25% (n=86) of cases with exposure history had reported being imprisoned in the 24 months prior to diagnosis. Of these cases, approximately 87% (n=75) also reported a history of injecting drug use. However, it is important to note that screening rates are generally higher in the prison entry population than the general population. A screening survey of prison entrants conducted over a 2-week period found that the prevalence of hepatitis C infection, based on hepatitis C antibody detection, was 22% in 2012, a decrease from 35% in 2007.³⁴

Unspecified hepatitis C

Epidemiological situation in 2014

In 2014, 10,249 cases of unspecified hepatitis C infections were notified to the NNDSS (43.7 per 100,000) compared with 10,339 cases in 2013 (44.7 per 100,000). Apart from slight rises from 2008–2009 and 2012–2013, notification rates have decreased annually since 2005. There was an overall decline of 24% between 2005 (57.6 per 100,000) and 2014 (43.7 per 100,000) (Figure 9).

Several factors may account for the decrease including changes in surveillance practices, removal of duplicate notifications and a gradual decline in the prevalent group of hepatitis C cases accumulated prior to the introduction of hepatitis C testing in the early 1990s.^25,35 The continuing decline in the notification rate may also be attributable to an apparent decrease in the prevalence of injecting drug use among young people in Australia.³³

Geographical distribution

For the past 10 years, the Northern Territory has reported the highest jurisdiction-specific notification rate for unspecified hepatitis C. In 2014, the Northern Territory’s notification rate was 72.8 per 100,000 (Table 5), which was 41% less than the 2005 rate of 123.6 per 100,000.

Age and sex distribution

Nationally in 2014, 66% (6,718/10,249) of unspecified hepatitis C notifications were in males (for cases where the sex was reported). The notification rate in males was 57.5 per 100,000 and in females 29.8 per 100,000; a male to female rate ratio of 1.9:1. Notification rates in males exceeded those in females across most age groups. The highest notification rates were among males in the 35–39 years (114.9 per 100,000) and 30–34 years (111.2 per 100,000) age groups. The highest notification rates among females were for those in the 30–34 years (60.2 per 100,000) and 35–39 years (56.9 per 100,000) age groups (Figure 12).

Figure 12: Notification rate for unspecified hepatitis C* infection, Australia, 2014, by age group and sex^†

* Data provided from Queensland includes both newly acquired and unspecified hepatitis C cases.

† Excludes 29 cases where age and/or sex were missing or unknown.

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Between 2005 and 2014, notification rates for unspecified hepatitis C infection have declined overall across all age groups, except for the 0–4 years age group for which rates remained relatively stable at 1.1 per 100,000 due to the low number of notifications. The largest decreases have occurred in the 20–29 years (from 111.6 to 58.3 per 100,000), the 30–39 years (117.8 to 86.2 per 100,000) and the 15–19 years (24.3 to 13.7 per 100,000) age groups (Figure 13).

Figure 13: Notification rate for unspecified hepatitis C* infection, Australia, 2005 to 2014, by year and selected age groups^†

* Data provided from Queensland (2005–2014) includes both newly acquired and unspecified hepatitis C cases.

† Excludes 54 cases where age was not reported (2005–2007 and 2009–2014).

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Hepatitis D

Hepatitis D is a defective single-stranded RNA virus that replicates in the presence of the hepatitis B virus. Hepatitis D infection can occur as either an acute co-infection with hepatitis B or as a super-infection with chronic hepatitis B infection. The modes of hepatitis D transmission are similar to those for hepatitis B.²²

Epidemiological situation in 2014

In Australia, the notification rate for hepatitis D infection remains low. In 2014, there were 59 notified cases of hepatitis D, representing a rate of 0.3 per 100,000 (Table 5). Over the preceding 9 years, notifications of hepatitis D remained relatively low with an average of almost 46 cases notified per year (range: 34 to 61).

Geographical distribution

In 2014, New South Wales reported the highest number of cases (19) followed by Victoria (14), Queensland (13), South Australia (9), Western Australia (3) and the Northern Territory (1). No cases were reported from the Australian Capital Territory or Tasmania during this period.

Age and sex distribution

Hepatitis D notifications in males exceeded those in females each year from 2005 to 2014. In 2014, 59% (35/59) of notifications were in males. This represented a male to female notification ratio of 1.5:1. This was less than the average notification ratio of 2.7:1 over the preceding 9 years (Figure 14).

Figure 14: Notifications of hepatitis D infection, Australia, 2005 to 2014, by year and sex

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