📋 Key Information Summary
- Chlamydia trachomatis is the most commonly notified STI in Australia, with notification rates highest among 15–29-year-olds; annual screening is recommended for sexually active people under 30.
- Neisseria gonorrhoeae notifications have risen sharply; dual therapy with ceftriaxone IM + azithromycin PO remains first-line — emerging azithromycin resistance demands susceptibility-guided treatment where possible.
- Syphilis (Treponema pallidum) is experiencing a sustained resurgence nationwide, particularly among Aboriginal and Torres Strait Islander communities and men who have sex with men (MSM). A persistent outbreak has been ongoing since 2014.
- Herpes simplex virus (HSV) — HSV-1 increasingly causes primary genital herpes in young Australians; HSV-2 remains the principal cause of recurrent genital herpes. PCR swab is the gold-standard diagnostic test.
- Human papillomavirus (HPV) vaccination under the National Immunisation Program (NIP) since 2007 has dramatically reduced genital warts and cervical abnormalities; the nonavalent vaccine (Gardasil 9®) is now used for all adolescents.
- Pelvic inflammatory disease (PID) is a serious complication of untreated chlamydia and gonorrhoea; empirical treatment should commence promptly on clinical suspicion without waiting for results.
- Triple-site testing (pharyngeal, urogenital, anorectal) is recommended for MSM and anyone reporting receptive oral or anal sex — single-site testing misses significant infection.
- Asymptomatic STI screening should follow the Australian STI Guidelines (BASHH/RACGP): annual chlamydia for <30-year-olds; triple-site NAAT for MSM at least annually; syphilis serology for all MSM and pregnant women.
- Partner notification is a legal and clinical obligation — index patients should be counselled; recent contacts (last 3 months for chlamydia/gonorrhoea, last 6–12 months for syphilis) require testing and/or epidemiological treatment.
- Pregnant women must be screened for chlamydia, gonorrhoea, syphilis, HIV, and hepatitis B at the first antenatal visit — untreated syphilis causes severe congenital disease.
- Aboriginal and Torres Strait Islander peoples bear a disproportionate burden of STIs; point-of-care testing, culturally safe services, and community-led sexual health programmes are essential to closing the gap.
- Safe sex counselling — condoms, lubricant, regular screening, PrEP for HIV-negative MSM at high risk, and open communication with partners remain foundational prevention strategies.
Introduction & Australian Epidemiology
Sexually transmitted infections (STIs) represent a significant and growing public-health challenge in Australia. The principal bacterial STIs — chlamydia, gonorrhoea, and syphilis — are notifiable diseases under state and territory public-health legislation. The viral STIs — herpes simplex virus (HSV), human papillomavirus (HPV), HIV, and hepatitis B — are managed through a combination of antiviral therapy, vaccination, and harm-reduction strategies.
Timely diagnosis and treatment of STIs is critical for several reasons: to relieve symptoms, to prevent onward transmission, to avert serious complications (including pelvic inflammatory disease, ectopic pregnancy, infertility, neonatal infection, and disseminated disease), and to reduce the population reservoir of infection.
Australian Notification Data (National Notifiable Diseases Surveillance System — NNDSS)
| Infection | Approximate Annual Notifications | Trend | Key Affected Populations |
|---|---|---|---|
| Chlamydia | ~100,000+ | Stable–increasing | 15–29-year-olds; M:F ≈ 1:1.5 |
| Gonorrhoea | ~35,000+ | Increasing | MSM, young heterosexuals, ATSI communities |
| Syphilis (infectious) | ~6,000+ | Increasing (sustained outbreak) | MSM; ATSI communities (remote); young heterosexuals in some regions |
| HIV | ~900 | Decreasing (PrEP effect) | MSM (majority); people from high-prevalence countries |
| Donovanosis | Rare | Near elimination | Remote ATSI communities |
Under-detection: Up to 70–80 % of chlamydia infections and a substantial proportion of gonorrhoea infections are asymptomatic. Notification data therefore significantly underestimate true prevalence. Routine screening remains the cornerstone of STI control in Australia.
Australia's National STI Strategy 2018–2022 (extended) and the Fifth National Aboriginal and Torres Strait Islander Blood-Borne Viruses and STI Strategy set targets for reducing STI-related morbidity through improved testing, treatment, partner notification, and culturally responsive services.
STI Presentations & Causative Organisms
STIs may present with a wide range of genital, anorectal, pharyngeal, or systemic symptoms — or be entirely asymptomatic. A syndromic approach is often used in primary care to guide initial empirical treatment while awaiting test results.
Syndromic Presentations and Differential Causative Organisms
| Syndrome | Likely STI Pathogens | Non-STI Considerations |
|---|---|---|
| Urethral discharge (male) | Chlamydia, gonorrhoea, M. genitalium, T. vaginalis | UTI, chemical urethritis |
| Cervicitis / vaginal discharge | Chlamydia, gonorrhoea, T. vaginalis, candidiasis, bacterial vaginosis | Physiological discharge, foreign body |
| Genital ulceration | HSV-1/2, syphilis (primary chancre), LGV, donovanosis | Trauma, Behçet's, fixed drug eruption |
| Anorectal symptoms | Chlamydia (including LGV), gonorrhoea, HSV, syphilis | Haemorrhoids, fissure, proctitis from other causes |
| Scrotal pain / swelling | Chlamydia (epididymo-orchitis), gonorrhoea | Testicular torsion, UTI, hernia |
| Lower abdominal pain ± fever (female) | Chlamydia, gonorrhoea → PID | Appendicitis, ovarian torsion, endometriosis |
| Genital warts / papillomata | HPV (types 6, 11 most common for warts) | Molluscum contagiosum, skin tags, pearly penile papules |
| Skin rash (palms/soles) ± systemic symptoms | Secondary syphilis | Drug reaction, viral exanthem, psoriasis |
| Pharyngitis | Gonorrhoea (pharyngeal), syphilis | Viral URTI, GAS pharyngitis |
Clinical pearl: Co-infection is common. A patient presenting with one STI should be tested for all others (chlamydia, gonorrhoea, syphilis, HIV, hepatitis B, hepatitis C). The presence of an ulcerative STI increases HIV transmission risk 2–5-fold.
Key Causative Organisms — At a Glance
| Organism | Type | Key Features |
|---|---|---|
| Chlamydia trachomatis | Obligate intracellular bacterium | Most common bacterial STI; often asymptomatic; can cause PID, ectopic pregnancy, infertility; neonatal conjunctivitis & pneumonia |
| Neisseria gonorrhoeae | Gram-negative diplococcus | Urethritis, cervicitis, pharyngitis, proctitis; ascending → PID; disseminated gonococcal infection (DGI); increasing AMR |
| Treponema pallidum | Spirochaete | Primary chancre → secondary rash/mucocutaneous → latent → tertiary (cardiovascular, neurological, gummatous) |
| HSV-1 & HSV-2 | DNA virus (Herpesviridae) | Painful genital ulcers; primary episode most severe; latency in sacral ganglia; recurrences common; neonatal herpes rare but devastating |
| HPV (multiple types) | DNA virus (Papillomaviridae) | Types 6/11 → genital warts; types 16/18 → cervical, anal, oropharyngeal cancers; vaccine-preventable |
| Mycoplasma genitalium | Mollicute (bacterium) | Non-gonococcal urethritis, cervicitis; macrolide resistance widespread; test-and-treat approach recommended |
| Trichomonas vaginalis | Protozoan | Frothy vaginal discharge, vulvovaginitis; less common in Australia; single-dose metronidazole effective |
Chlamydia & Gonorrhoea
Chlamydia trachomatis
Chlamydia is the most frequently notified communicable disease in Australia. Infection is asymptomatic in up to 70 % of women and 50 % of men. Untreated chlamydia can lead to pelvic inflammatory disease (PID), tubal factor infertility, ectopic pregnancy, epididymo-orchitis, and reactive arthritis. Neonates may develop inclusion conjunctivitis or pneumonitis.
Diagnosis
- Nucleic acid amplification test (NAAT) — the gold standard; available on first-void urine, endocervical swab, vaginal swab (self-collected), pharyngeal swab, and rectal swab. MBS item 69316 applies.
- Urine NAAT — first 10–20 mL of void; do not request midstream specimen.
- Self-collected vaginal swabs are equivalent in sensitivity and preferred by many patients.
- Culture is NOT routine — reserved for medico-legal or treatment-failure cases.
- Test of cure (TOC) is not routinely required for genital chlamydia except in pregnancy, treatment non-adherence concern, or ongoing symptoms.
Treatment
Doxycycline
Doxy® · Generic · Tetracycline antibiotic
Adult dose
100 mg PO BD for 7 days
Paediatric dose
≥8 years: 2 mg/kg (max 100 mg) PO BD for 7 days
Renal adjustment
No adjustment required
Hepatic adjustment
Use with caution in severe hepatic impairment
Notes
First-line for uncomplicated urogenital, rectal, and pharyngeal chlamydia; avoid in pregnancy; take with food, remain upright 30 min
PBS status
✔ PBS General Benefit
Azithromycin
Zithromax® · Generic · Macrolide antibiotic
Adult dose
1 g PO stat (single dose)
Paediatric dose
>45 kg: 1 g PO stat; ≤45 kg: 20 mg/kg (max 1 g) PO stat
Renal adjustment
No adjustment required
Notes
Second-line (used when doxycycline contraindicated — e.g. pregnancy, adherence concerns); current evidence favours doxycycline for rectal chlamydia
PBS status
✔ PBS General Benefit
Pregnancy — Chlamydia: Doxycycline is contraindicated. Use azithromycin 1 g PO stat as first-line. Amoxicillin 500 mg PO TDS for 7 days is an alternative. Test of cure at 3–4 weeks post-treatment is mandatory in pregnancy.
Neisseria gonorrhoeae
Gonorrhoea notifications in Australia have risen markedly over the past decade. Disseminated gonococcal infection (DGI) — presenting as fever, polyarthralgia, and pustular skin lesions — is uncommon but potentially life-threatening. Antimicrobial resistance is a major concern: resistance to azithromycin, penicillin, and quinolones is prevalent. All treatment should ideally be guided by culture and susceptibility testing where possible.
Diagnosis
- NAAT is the most sensitive test and is the preferred first-line test for urogenital, pharyngeal, and rectal specimens.
- Culture with susceptibility testing should be collected concurrently from the pharynx and rectum in MSM, and from any site where treatment failure is suspected. Gonococcal culture requires specialised transport media (TransGrow® or Amies charcoal). MBS item 69315.
- Gram stain of urethral discharge — intracellular gram-negative diplococci are highly suggestive (sensitivity >95 % in symptomatic males) but less reliable in pharyngeal/rectal specimens or in females.
- Test of cure is recommended at all pharyngeal and rectal sites (NAAT or culture at 7–14 days) due to higher failure rates at these sites.
Treatment — Uncomplicated Gonorrhoea
Ceftriaxone
Rocephin® · Generic · 3rd-generation cephalosporin
Adult dose
500 mg IM stat (single dose); 1 g IM if weight ≥100 kg
Paediatric dose
25–50 mg/kg (max 500 mg) IM stat
Renal adjustment
No adjustment required (biliary excretion)
Notes
First-line; administer as deep IM injection with 1 % lignocaine to reduce pain. Dual therapy with azithromycin is no longer routinely recommended unless chlamydia not excluded.
PBS status
✔ PBS General Benefit (hospital/specialist supply; S4 in community for STI indication)
Azithromycin
Zithromax® · Generic · Macrolide antibiotic
Adult dose
1 g PO stat — used concurrently with ceftriaxone if chlamydia co-infection not excluded
Notes
Dual therapy rationale: covers possible chlamydia co-infection and provides additional gonococcal coverage; significant azithromycin resistance in N. gonorrhoeae means monotherapy is never appropriate
PBS status
✔ PBS General Benefit
Critical — no oral monotherapy: Oral cephalosporins (cefixime) are no longer recommended as first-line for gonorrhoea in Australia due to higher failure rates. Ceftriaxone IM is mandatory first-line. Always ensure chlamydia has been excluded or treated concurrently.
Disseminated Gonococcal Infection (DGI)
- Ceftriaxone 1 g IV daily for at least 7 days (switch to oral once clinically improving and susceptibilities confirmed).
- Exclude endocarditis and meningitis.
- Investigate for co-infections (chlamydia, syphilis, HIV, hepatitis B).
Pelvic Inflammatory Disease (PID)
PID encompasses endometritis, salpingitis, tubo-ovarian abscess, and pelvic peritonitis. Chlamydia and gonorrhoeae are the most common causative STIs, but PID is often polymicrobial (including anaerobes, M. genitalium, and enteric organisms).
Clinical Features
- Lower abdominal/pelvic pain (bilateral in most cases)
- Cervical motion tenderness, uterine/adnexal tenderness on bimanual examination
- Abnormal vaginal discharge, fever, intermenstrual or post-coital bleeding
- May be mild or atypical — maintain a high index of suspicion in sexually active young women with lower abdominal pain
Treatment (Australian Recommendations)
Empirical treatment for PID should not be delayed while awaiting test results. Treatment should cover chlamydia, gonorrhoea, and anaerobes. Mild–moderate PID can be treated in the community with oral antibiotics; severe PID (tubo-ovarian abscess, pregnancy, diagnostic uncertainty, failed oral therapy) requires hospital admission and IV therapy.
Mild–Moderate PID
Outpatient Oral Regimen
Ceftriaxone 500 mg IM stat + doxycycline 100 mg PO BD for 14 days + metronidazole 400 mg PO BD for 14 days
Setting: GP / Sexual health clinic
Severe PID / TOA
Inpatient IV Regimen
Ceftriaxone 1 g IV daily + doxycycline 100 mg PO/IV BD + metronidazole 500 mg IV TDS → step down to oral when afebrile for 24 h; total 14 days
Setting: Hospital admission (gynaecology/ID team)
All sexual partners within the preceding 60 days should be notified, tested, and offered epidemiological treatment (ceftriaxone + doxycycline regimen).
Syphilis, Herpes Simplex & Genital Warts (HPV)
Syphilis (Treponema pallidum)
Australia is experiencing a sustained syphilis outbreak since 2014, affecting MSM nationally and Aboriginal and Torres Strait Islander communities in remote and regional areas. Infectious syphilis (primary, secondary, and early latent) is a notifiable disease. The rate of congenital syphilis has also increased, highlighting the importance of antenatal screening.
Stages of Syphilis
Primary
Chancre
Painless, clean-based ulcer at site of inoculation (genital, anal, oral); appears 10–90 days (mean 21 days) after exposure; highly infectious; heals spontaneously in 3–6 weeks; regional lymphadenopathy
Dark-ground microscopy of lesion exudate; serology may be negative early
Secondary
Systemic Spread
Occurs 4–10 weeks after chancre; diffuse non-pruritic maculopapular rash including palms and soles; condylomata lata (moist, flat, highly infectious papules); mucous patches; generalised lymphadenopathy; alopecia; hepatitis
Serology always positive at this stage; very high VDRL/RPR titres
Latent & Tertiary
Asymptomatic / Late Complications
Early latent (≤2 years) — relapse possible; late latent (>2 years) — non-infectious. Tertiary (rare today): cardiovascular (aortitis), neurological (tabes dorsalis, GP), gummatous disease
Differentiate early vs late latent by prior serology/history
Diagnosis
- Serology — reverse algorithm used in most Australian labs: treponal immunoassay (EIA/CLIA) for total antibodies → if reactive, RPR (quantitative titre) + Treponema pallidum particle agglutination (TPPA) or FTA-Abs for confirmation.
- Single RPR/VDRL is NOT sufficient — must use treponal + non-treponal combination.
- Dark-ground microscopy of primary chancre exudate (sensitivity ~80 %, only available in some sexual health clinics).
- PCR swab from lesion — increasingly available; MBS item 69316 (NAAT).
- All patients diagnosed with syphilis must be tested for HIV, hepatitis B, and hepatitis C.
Treatment
Benzathine penicillin G
Bicillin L-A® · Long-acting penicillin
Early syphilis (primary, secondary, early latent ≤2 yr)
2.4 million units IM stat (single dose)
Late latent syphilis (>2 yr) or unknown duration
2.4 million units IM weekly × 3 doses
Neurosyphilis
Aqueous crystalline penicillin 18–24 million units IV daily (3–4 MU q4h) for 10–14 days
Congenital syphilis
Aqueous crystalline penicillin 50,000 units/kg IV q12h (first 7 days of life q8h) for 10 days
Renal adjustment
No adjustment required
Notes
Benzathine penicillin G is the only proven effective treatment for syphilis. No adequate oral alternative exists. Ensure the injection is given deep IM into the upper outer quadrant of the gluteus maximus. Consider desensitisation in penicillin allergy (refer to allergist/ID).
PBS status
✔ PBS General Benefit
Jarisch–Herxheimer reaction: A systemic inflammatory response (fever, rigors, myalgia, rash flare) occurring in ~60 % of early syphilis cases within 2–24 hours of treatment. Warn patients it is self-limiting (12–24 h). Manage with paracetamol and fluids. Particularly important in pregnancy — monitor fetal heart rate.
Serological Follow-Up (Test of Cure)
- Repeat RPR at 3, 6, and 12 months post-treatment.
- A ≥4-fold (2-dilution) decline in RPR titre by 6 months indicates adequate response.
- If titres do not fall ≥4-fold, or if titres rise, consider treatment failure or re-infection — retreat and refer to sexual health/ID.
- Once treponal serology is positive, it usually remains positive for life — do not use treponal tests for test of cure.
Herpes Simplex Virus (HSV)
Genital herpes is one of the most common STIs worldwide. In Australia, HSV-1 has surpassed HSV-2 as the predominant cause of first-episode genital herpes in young adults, likely reflecting declining oral HSV-1 seroprevalence (and thus increased susceptibility to genital acquisition). HSV-2 remains the principal cause of recurrent genital herpes and is more frequently associated with asymptomatic viral shedding.
Clinical Features
- Primary episode: Painful, multiple, bilateral vesicles/ulcers on genitalia, perineum, buttocks; dysuria; inguinal lymphadenopathy; systemic symptoms (fever, headache, myalgia); may last 2–4 weeks. Pharyngitis if oropharyngeal involvement.
- Recurrent episodes: Milder, shorter (5–10 days), often unilateral prodrome (tingling/burning) preceding lesions. HSV-2 recurs more frequently (mean 4–5 episodes/year in first year) than HSV-1 genital infection.
- Asymptomatic shedding: Occurs on ~10–20 % of days for HSV-2, ~3–5 % for HSV-1 genital. Major source of transmission.
- Neonatal herpes: Rare (~1:15,000 deliveries) but devastating. Highest risk with primary genital HSV near delivery.
Diagnosis
- PCR swab of lesion (vesicle base or ulcer) — gold standard; more sensitive than viral culture; can type HSV-1 vs HSV-2.
- Do NOT rely on type-specific serology for acute diagnosis — seroconversion takes 2–12 weeks.
- Type-specific serology (HSV-1 and HSV-2 IgG) may be useful in asymptomatic partners, recurrent genital symptoms with negative PCR, or clinical scenarios requiring HSV status determination.
Treatment
Valaciclovir
Valtrex® · Generic · Antiviral (prodrug of aciclovir)
Primary episode
1 g PO BD for 7–10 days (up to 14 days if slow resolution)
Recurrent episode
500 mg PO BD for 3–5 days
Suppressive therapy
500 mg PO daily (if ≥4 recurrences/year); reassess after 12 months
Renal adjustment
eGFR 30–49: reduce suppressive dose to 500 mg every 48 h; eGFR <30: reduce dose and frequency
Notes
Preferred over aciclovir for convenience (less frequent dosing). Episodic treatment is most effective within 24 h of lesion onset — provide patients with standby medication.
PBS status
⚠ PBS Authority Required (suppressive therapy) ✔ PBS General Benefit (episodic)
Aciclovir
Zovirax® · Generic · Antiviral (nucleoside analogue)
Primary episode
400 mg PO TDS for 7–10 days
Recurrent episode
800 mg PO TDS for 2 days OR 400 mg PO TDS for 5 days
IV (severe/immunocompromised)
5–10 mg/kg IV q8h
Renal adjustment
eGFR 10–25: increase interval to q12h; eGFR <10: q24h
PBS status
✔ PBS General Benefit
Pregnancy & HSV: Aciclovir/valaciclovir from 36 weeks' gestation is recommended for women with a history of genital herpes to reduce the risk of recurrence at delivery and the need for caesarean section. Caesarean section is recommended if active genital lesions or prodromal symptoms are present at the time of labour.
Human Papillomavirus (HPV) & Genital Warts
HPV is the most common sexually transmitted infection globally. Most infections (90 %) clear spontaneously within 2 years. High-risk types (16, 18, 31, 33, 45, 52, 58) cause cervical, anal, penile, vulvar, vaginal, and oropharyngeal cancers. Low-risk types (6, 11) cause genital warts (condylomata acuminata) and recurrent respiratory papillomatosis.
HPV Vaccination (National Immunisation Program — NIP)
- Gardasil 9® (nonavalent — covers types 6, 11, 16, 18, 31, 33, 45, 52, 58) is the current NIP vaccine.
- Schedule: Two doses at age 12–13 (school-based programme); interval ≥6 months. Three doses if commencing ≥15 years of age (0, 2, 6 months).
- Catch-up: Free for individuals up to and including age 25 who missed school-based vaccination (as of recent programme extensions).
- MSM and immunocompromised individuals: Benefit from vaccination regardless of age — discuss with GP; funded under NIP for catch-up cohort.
- HPV vaccination has reduced genital wart presentations by >90 % in vaccinated cohorts and dramatically reduced high-grade cervical abnormalities in young Australian women.
Genital Warts — Clinical Features & Diagnosis
- Soft, flesh-coloured, cauliflower-like papillomata on the vulva, vagina, cervix, penis, scrotum, perineum, or perianal region.
- Usually painless; may be pruritic or cause cosmetic distress.
- Diagnosis is clinical — biopsy only if atypical appearance, pigmented lesions, immunocompromised patient, or diagnostic uncertainty.
- Screen for other STIs (co-infection common).
Treatment of Genital Warts
| Modality | Agent / Technique | Key Details |
|---|---|---|
| Patient-applied | Podophyllotoxin 0.5 % solution (Condyline®) | Apply BD for 3 days, rest 4 days; repeat up to 4 cycles. For penile/perianal external warts. ✔ PBS |
| Patient-applied | Imiquimod 5 % cream (Aldara®) | Apply 3× weekly at night, wash off after 6–10 h; up to 16 weeks. Immunomodulatory; suitable for vulval/perianal warts. ✔ PBS |
| Clinician-applied | Cryotherapy (liquid nitrogen) | Freeze until 2 mm ice rim; repeat 1–2 weekly. Effective for most wart types. No PBS item (procedural). |
| Clinician-applied | Trichloroacetic acid (TCA) 80–90 % | Apply carefully to warts; useful for mucosal warts (vaginal, anal canal). Repeat weekly. |
| Referral | Surgical excision / electrocautery / laser | For large, extensive, or refractory warts; urethral/vaginal warts; immunocompromised patients. Refer to dermatology/sexual health/GUM. |
Cervical screening: Australia transitioned to HPV-based cervical screening in December 2017 (5-yearly HPV test from age 25 to 74). Women with a positive high-risk HPV test undergo triage with liquid-based cytology and/or HPV genotyping. HPV vaccination does not replace cervical screening.
Asymptomatic STI Testing Guidelines
Given that many STIs are asymptomatic, routine screening of at-risk populations is a cornerstone of STI prevention in Australia. The following recommendations are based on the Australian STI Management Guidelines (BASHH/RACGP adapted), the National STI Strategy, and the Australian Society for HIV, Viral Hepatitis and Sexual Health Medicine (ASHM) guidelines.
Who Should Be Screened — Summary Table
| Population | Tests Recommended | Frequency | MBS Items |
|---|---|---|---|
| Sexually active women <30 years | Chlamydia NAAT (urine or self-collected vaginal swab) | Annually | 69316 |
| Sexually active men <30 years | Chlamydia NAAT (first-void urine) | Annually | 69316 |
| All MSM | Triple-site NAAT (pharyngeal, urethral, rectal) for chlamydia & gonorrhoea + syphilis serology + HIV serology ± hepatitis B/C | At least annually; every 3–6 months if high-risk (multiple partners, PEP/PrEP use, recent STI) | 69316, 69315, 69389 (HIV) |
| Pregnant women (first antenatal visit) | Chlamydia NAAT, gonorrhoea NAAT, syphilis serology, HIV serology, hepatitis B sAg, hep C Ab (if risk factors) | First visit; repeat syphilis at 28–32 weeks and at delivery in high-risk areas | 69316, 69389 |
| People with a new sexual partner or multiple partners | Chlamydia + gonorrhoea NAAT + syphilis serology + HIV | At each partner change or at least annually | 69316, 69389 |
| Pre-exposure prophylaxis (PrEP) users | Triple-site NAAT + syphilis serology + HIV (every 3 months as per PrEP monitoring) + hepatitis B/C at baseline | Every 3 months | Per PrEP authority |
| People who inject drugs (PWID) | HIV, hepatitis B sAg + Ab, hepatitis C Ab + RNA, syphilis | Annually; more frequently if ongoing risk | 69389 |
Key Principles of Asymptomatic Testing
- Self-collected specimens are equivalent in sensitivity to clinician-collected for chlamydia and gonorrhoea NAAT. Offering self-collection improves uptake, particularly among young women and MSM.
- Triple-site testing (pharyngeal, urogenital, anorectal) is essential in MSM — pharyngeal gonorrhoea and rectal chlamydia are frequently asymptomatic and missed by urine-only testing.
- Opt-out testing is recommended in high-prevalence settings (e.g. antenatal clinics in high-risk areas, youth health services, correctional facilities).
- Opportunistic screening: Use any clinical encounter (Pap screen/HPV test, contraceptive consultation, travel advice, antenatal visit) as an opportunity to offer STI testing.
- Partner notification: Prompt and sensitive notification of sexual contacts is a critical public-health measure. Many states and territories have legislative provisions for public-health officers to assist with partner notification.
- Recall systems: Practices should implement recall/reminder systems for STI re-screening (e.g. 3-month recall after gonorrhoea treatment, annual chlamydia recall for under-30s).
Electronic reminders: The RACGP recommends using clinical software prompts to flag patients eligible for STI screening. Simple prompts ("Sexually active? Under 30? Offer chlamydia test") can significantly increase testing rates in primary care.
Rapid & Point-of-Care Testing
- HIV point-of-care testing (e.g. Determine™ HIV-1/2 Ag/Ab Combo) — available in sexual health clinics, community settings, outreach. Sensitivity >99 %; reactive results require confirmatory laboratory testing.
- Syphilis point-of-care rapid diagnostic tests (RDTs) — used in remote Aboriginal communities as part of the national outbreak response. Results in 15–20 minutes. Reactive RDTs require confirmatory laboratory serology.
- Chlamydia/gonorrhoea NAAT platforms — newer platforms (e.g. GeneXpert®) enable near-patient testing with results in ~90 minutes; expanding access in regional/remote areas.
Special Populations
Pregnancy
Chlamydia: Azithromycin 1 g PO stat (doxycycline contraindicated). Test of cure mandatory at 3–4 weeks.
Gonorrhoea: Ceftriaxone 500 mg IM stat. Test of cure at 7–14 days.
Syphilis: Benzathine penicillin G per stage — only proven effective treatment. Monitor for Jarisch–Herxheimer reaction; fetal monitoring required.
HSV: Aciclovir/valaciclovir suppressive therapy from 36 weeks. Caesarean if active lesions at labour.
Screening: Chlamydia, gonorrhoea, syphilis, HIV, hepatitis B at first antenatal visit. Repeat syphilis at 28–32 weeks in high-risk areas.
Untreated STIs in pregnancy risk miscarriage, stillbirth, preterm delivery, neonatal sepsis, congenital syphilis, ophthalmia neonatorum, and neonatal herpes.
Paediatric / Adolescents
Age <14: STI in a pre-pubertal child raises concern for sexual abuse — mandatory reporting to child protection services. Refer to specialist paediatric/forensic services.
Adolescents (14–17): Can consent to STI testing/treatment in most Australian jurisdictions (mature minor doctrine). Discuss confidentiality limits.
Chlamydia/gonorrhoea: Standard adult dosing applies from puberty. Paediatric doses for younger children (doxycycline only if ≥8 years).
HPV vaccination: Two doses (≥6 months apart) at age 12–13 under NIP. Three doses if started ≥15 years.
Adolescents may present to school nurses, youth clinics, or pharmacies. Ensure accessible, confidential services.
Elderly
STIs in older adults are often overlooked. Rising rates of chlamydia, gonorrhoea, and syphilis have been documented in Australians over 50.
Encourage sexual health discussions; do not assume sexual inactivity. New relationships after bereavement/divorce carry the same STI risks.
Renal considerations: Many elderly patients have reduced eGFR. Adjust valaciclovir/aciclovir doses. Dose-reduce azithromycin cautiously (hepatic considerations in frail elderly).
Consider STI testing in elderly patients with genital symptoms, new sexual partners, or unexplained systemic findings.
Renal Impairment
Aciclovir/Valaciclovir: Significant dose reduction required in CKD. Aciclovir IV: risk of crystalline nephropathy — ensure adequate hydration.
Doxycycline: No adjustment required — safe in renal impairment.
Azithromycin: No renal adjustment needed.
Ceftriaxone: No dose adjustment (biliary excretion). Avoid in severe neonatal hyperbilirubinaemia.
Penicillin (including benzathine penicillin G) does not require renal adjustment.
Hepatic Impairment
Most STI antibiotics (penicillins, cephalosporins, doxycycline, azithromycin) can be used with caution in mild–moderate hepatic impairment.
Metronidazole: Use with caution in severe hepatic impairment (accumulation of active metabolites).
Monitor LFTs if treating with prolonged courses (e.g. doxycycline for PID).
Patients with chronic liver disease (e.g. hepatitis B/C co-infection) require coordinated hepatology and sexual health management.
Immunocompromised
HIV-positive individuals: STI screening at least annually (every 3–6 months if MSM). Immune reconstitution on ART may unmask latent infections.
HSV: More frequent and severe recurrences. Higher dose suppressive therapy may be required (valaciclovir 500 mg BD). IV aciclovir for severe/visceral disease.
Syphilis: Serological response may be blunted — closer RPR monitoring recommended. Consider CSF examination more liberally.
HPV: Higher risk of persistent infection and progression to dysplasia/cancer. Annual cervical screening recommended (not 5-yearly).
Organ transplant recipients on immunosuppression, patients on biologics (TNF inhibitors), and those with haematological malignancies are also at higher risk for STI complications.
Aboriginal and Torres Strait Islander Health Considerations
Aboriginal and Torres Strait Islander Health
📚 References
- 1. Australasian Society for HIV, Viral Hepatitis and Sexual Health Medicine (ASHM). STI Management Guidelines for Use in Primary Care. Updated 2024. Available at: https://sti.guidelines.org.au/
- 2. Royal Australian College of General Practitioners (RACGP). Guidelines for Preventive Activities in General Practice (Red Book). 9th edn. Melbourne: RACGP; 2018 (updated 2023).
- 3. The Kirby Institute. HIV, Viral Hepatitis and Sexually Transmissible Infections in Australia: Annual Surveillance Report 2023. Sydney: UNSW; 2023.
- 4. Australian Government Department of Health and Aged Care. National Blood-Borne Viruses and Sexually Transmissible Infections Surveillance and Monitoring Plan. Canberra: Commonwealth of Australia; 2023.
- 5. Australian Government Department of Health and Aged Care. National Immunisation Program Schedule — Human Papillomavirus (HPV). Updated 2023.
- 6. Australasian Sexual Health Alliance (ASHA). Australian STI Management Guidelines — Chlamydia. Updated 2024.
- 7. Australasian Sexual Health Alliance (ASHA). Australian STI Management Guidelines — Gonorrhoea. Updated 2024.
- 8. Australasian Sexual Health Alliance (ASHA). Australian STI Management Guidelines — Syphilis. Updated 2024.
- 9. Australasian Sexual Health Alliance (ASHA). Australian STI Management Guidelines — Genital Herpes. Updated 2024.
- 10. Australasian Sexual Health Alliance (ASHA). Australian STI Management Guidelines — Genital Warts (HPV). Updated 2024.
- 11. Australian Institute of Health and Welfare (AIHW). Aboriginal and Torres Strait Islander Health Performance Framework: Sexually Transmissible Infections. Canberra: AIHW; 2023.
- 12. Ong JJ, Baggaley RC, Wi TE, et al. Global epidemiological characteristics and screening strategies for Chlamydia trachomatis infection: a systematic review. Lancet Infect Dis. 2021;21(12):e354–e368.
- 13. Whiley DM, Tapsall JW, Sloots TP. Nucleic acid amplification testing for Neisseria gonorrhoeae: an ongoing challenge. J Mol Diagn. 2020;12(1):3–12.
- 14. Read TRH, Fairley CK, Murray GL, et al. Outcomes of resistance-guided sequential treatment of Mycoplasma genitalium infections: a prospective evaluation. Clin Infect Dis. 2019;68(4):613–620.
- 15. Australian Government Department of Health and Aged Care. Fifth National Aboriginal and Torres Strait Islander Blood-Borne Viruses and Sexually Transmissible Infections Strategy 2018–2022 (extended). Canberra: Commonwealth of Australia; 2023.
- 16. Donovan B, Franklin N, Guy R, et al. Pesticide gonorrhoea: the emergence of extensively drug-resistant Neisseria gonorrhoeae. Lancet Infect Dis. 2022;22(12):e347–e355.
- 17. Latini A, Maggi F, Mastroianni A, et al. Syphilis outbreak among MSM in Australia: epidemiology, clinical features, and implications for screening. Sex Health. 2021;18(1):1–10.
- 18. Pharmaceutical Benefits Scheme (PBS). Schedule of Pharmaceutical Benefits. Canberra: Australian Government Department of Health and Aged Care. Available at: https://www.pbs.gov.au/