Red Book

Communicable diseases

Sexually transmissible infections

Sexually transmissible infections (STIs) are frequently seen in general practice, especially chlamydia, which is typically asymptomatic.5,6 It is important to detect it early in order to prevent transmission to others and minimise potential complications, such as infertility. It may also be appropriate to screen for other STIs. The individual’s age, sexual behaviour and community HIV or STI prevalence all influence the level of risk, and should influence the choice of STI screening tests.

For additional resources specific to Aboriginal and Torres Strait Islander peoples, The Royal Australian College of General Practitioners’ (RACGP) National guide to a preventive health assessment for Aboriginal and Torres Strait Islander people (2nd edn)includes information about sexual health and blood-borne viruses.

Many patients and doctors feel uncomfortable discussing sexual histories even when indicated or the patient is requesting STI testing. Taking a sexual history is an important part of the assessment and management of STIs, and it should not be a barrier to offering STI testing.7

A non-judgmental attitude and environment will facilitate disclosures on sexual matters.8 It is important to ask open-ended questions and to avoid assumptions about sexual orientation, by using the term ‘partner’. Gentle enquiry about recent sexual activity, gender, number of partners, contraception (including use of condoms), travel history, and immunisation status helps to inform decision making. Additionally, ask about the risk for blood-borne viruses (hepatitis B, C, and HIV), such as injecting drug use, tattooing and piercing. Investigations should be explained, and patients should be asked for consent before tests such as HIV or hepatitis C are ordered.

Contact tracing is essential in reducing the transmission of STIs and HIV. It is the responsibility of the diagnosing clinician to facilitate the process of notifying current and past partners. This may be through a direct approach from the patient, their treating health professional, or by using online partner notification services available such as:

For more information and to determine ‘how far back to trace’, refer to the contact tracing manual at the Australasian Society of HIV, Viral Hepatitis and Sexual Health Medicine’s (ASHM) website or the the NSW STI Programs Unit STI / HIV Testing Tool

For HIV contact tracing, seek assistance from local sexual health services.

In the case of a notifiable condition, the patient should be informed that case notification to public health authorities will occur. Notification should be made as set by the department of health in the relevant state or territory.


Age range chart

0-9 10-14 15-19 20-24 25-29 30-34 35-39 40-44 45-49 50-54 55-59 60-64 65-69 70-79 >80

More than 80% of chlamydia infections occur in people <29 years of age.9 Screening for chlamydia infection in all sexually active people up to 29 years of age is recommended because of increased prevalence and risk of complications.10 In asymptomatic, sexually active people up to 29 years of age, the overall absolute risk of infection is approximately 5% for chlamydia and 0.5% for gonorrhoea.

The ranked risk for specific infections per 100,000 in general population/Aboriginal and Torres Strait Islander populations:11

  • Chlamydia (371/1341)
  • Gonorrhoea (49/858)
  • Hepatitis B (23/50)
  • Syphilis (8/32)
  • HIV (4/6)

A large proportion of young people will attend primary care clinics each year, and this presents the opportunity to normalise sexual health care as part of usual general practice.10 Younger sexually active youths should not be excluded from case finding, or identifying any safety or abuse issues. This may involve a complete psychosocial (HE2ADS3)12 risk assessment as discussed in Table 3.2.

Women with untreated chlamydia infections have a 2–8% risk of infertility.13 Other STIs to consider screening for in higher risk individuals are gonorrhoea, HIV and syphilis.14 The risk for gonorrhoea, HIV and syphilis is low for heterosexuals in all major cities in Australia and New Zealand,15 but rates of gonorrhoea and syphilis are higher among MSM. The individual’s age and sexual habits, and community STI prevalence all influence the level of risk and should guide STI testing recommendations for patients (refer to Tables and for guidance).

MSM should be screened for gonorrhoea, chlamydia, syphilis and HIV every 12 months. Screening should be performed more often if they have multiple sexual contacts. Most MSM with STIs have no symptoms.16

Aboriginal and Torres Strait Islander peoples are at higher risk and should also be screened for gonorrhoea, chlamydia, syphilis and HIV.

Screening for hepatitis C should be provided if the patient is HIV positive or there is a history of injecting drug use, as this increases the risk of transmission.16

All pregnant women should be screened for hepatitis B, C, HIV and syphilis.14,17,18 Consider screening pregnant women up to 29 years of age for chlamydia (and also gonorrhoea, if the patient is at high risk).17–20

. Sexually transmissible infections: Identifying risks


Sexually transmissible infections: Identifying risks

Tests to detect sexually transmissible infections


Tests to detect sexually transmissible infections


Chlamydia is the most common and curable STI in Australia. Notification rates per 100,000 increased from 35.4 in 1993 to 363 in 2011, and has been steady since; 78% of those infected are aged 15–29 years.11Young Aboriginal and Torres Strait Islander peoples have higher infection rates especially in regional and remote areas, with a substantially increased risk of chlamydia, gonorrhoea and syphilis.10

Screening sexually active women <25 years of age for chlamydia on an annual basis has been shown to halve the infection and complication rates.11,13,35

Treatment of partners and contact tracing

All partners of those infected should be tested and treated presumptively. A systematic review has shown that providing patient-delivered partner therapy to index cases is more effective in reducing infection rates than paper-based methods of contact tracing.36 There is no single optimal strategy for contact tracing. Getting assistance from the local sexual health services is recommended for HIV and syphilis because it leads to more contacts being tested and treated.35 Referral to sexual health services should be considered for problematic or repeated infections.37

It is important to ensure current sexual partners are treated simultaneously. Untreated pregnant women infected with chlamydia have a 20–50% chance of infecting their infant at delivery.38

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