Delivering a Healthy WA
Disease WAtch

Trends in notifications of HIV infection in WA

In 2013, 119 new cases of HIV infection were notified in Western Australia, similar to the record number of 121 cases reported in 2012. HIV notifications in WA have increased steadily over the past decade to more than double the number of cases reported in 2004 (n=51). While HIV notifications have increased, notifications of AIDS and deaths in persons with HIV infection have remained relatively stable over this period (Figure 1).

In 2013, 94 males and 25 females were notified with HIV infection (male to female ratio 3.8:1). The median age of all HIV cases notified in 2013 was 37 years (range: 18 to 77 years) with the median age in males 6 years older than that in females (39 vs. 33 years).

Figure 1 -Number of notifications for HIV infection, AIDS and deaths in persons infected with HIV, WA, 1983 to 2013
Figure 1 – Number of notifications for HIV infection, AIDS and deaths in persons infected with HIV, WA, 1983 to 2013

Risk exposures

The rise in newly notified HIV infections in WA can be attributed to increases in notifications among both men who have sex with men (MSM) and people acquiring the virus through heterosexual exposures.

From 2004 to 2013, HIV notifications among MSM almost doubled from 31 to 58 new cases, with most of this increase occurring after 2009. In 2013, the majority of these men had acquired their infection in Australia (69%; n=40). There was a more dramatic almost 4-fold increase in the number of heterosexually acquired HIV notifications between 2004 and 2010 (17 to 66 cases), with a relative stabilisation since then (Figure 2). In 2013, most heterosexually acquired cases were infected overseas (83%; n=45), and the majority were male (61%; n=33).

Heterosexual acquisition was the most commonly reported risk exposure for HIV infection in WA between 2005 and 2012, accounting for more than half of all new cases over this period (54%; n=388). However, the disparity with MSM has decreased progressively since 2010, with MSM again becoming the most commonly reported risk exposure in 2013 (49%; n=58) (Figure 2).

Figure 2 - HIV notifications by exposure  category, WA residents, 2004 to 2013
Figure 2 – HIV notifications by exposure category, WA residents, 2004 to 2013

Trends by place of acquisition and birth among heterosexual cases

Most of the recent increase in heterosexually acquired cases was among overseas-born people who also acquired HIV infection overseas. Between 2004 and 2013, the number of cases reporting heterosexual exposure who were born and acquired their infections overseas increased from 7 to 34 cases, although the number has been relatively stable since 2009 (Figure 3). In 2013 the majority of these cases were sub-Saharan African born males (29%; n=10) and females born in sub-Saharan Africa (18%; n=6) or South-East Asia (18%; n=6). The majority of overseas born and acquired heterosexual cases from 2013 acquired HIV infection in their region of birth (79%; n=27).

Since 2010, notifications in Australian-born people who acquired HIV overseas, particularly in South-East Asia, have been relatively stable, comprising 20% of heterosexual cases in 2013 (Figure 3). The number of Australian-born, Australian-acquired heterosexual cases has remained relatively steady over the past 10 years, ranging between 4 and 11 cases per year.

Figure 3 - HIV notifications with a reported heterosexual exposure by place born and acquired, WA residents, 2004 to 2013
Figure 3 – HIV notifications with a reported heterosexual exposure by place born and acquired, WA residents, 2004 to 2013

HIV infection in Aboriginal people

The number of HIV notifications in Aboriginal people has remained low and relatively stable in recent years, and no new cases were notified among Aboriginal people in either 2012 or 2013 (Table 1). The age-standardised HIV notification rate has remained similar to, or lower than, the rate in non-Aboriginal people over this period.

Year Aboriginality Total Rate ratio (Aboriginal: Non-Aboriginal)
Aboriginal Non-Aboriginal
Number Per cent ASR Number Per cent ASR Number ASR
2009 3 3.3 5.3 87 96.7 4.1 90 4.1 1.3
2010 2 1.8 3.1 111 98.2 5.0 113 5.0 0.6
2011 5 4.8 6.0 100 95.2 4.4 105 4.4 1.4
2012 0 0.0 0.0 121 100.0 5.1 121 5.0 0.0
2013 0 0.0 0.0 119 100.0 4.9 119 4.8 0.0

Notes: ASR = Age-standardised notification rate per 100,000 population

Table 1 – Number and age-standardised rate of HIV notifications in WA by Aboriginality, 2009-2013

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