STI prevention

Currently, the following vaccines for viral STIs are available:

Human papillomavirus (HPV) vaccine (Gardasil 9)
- Funded up to age 27 years
- Should be routinely offered unless vaccination course complete
- May also have benefit in older patients depending on risk factors (unfunded)
Hepatitis B vaccine: limited indications for funding
Hepatitis A vaccine for those engaging in oral-anal sex (rimming) (unfunded indication)

Condoms are the most frequently used barrier method
Their efficacy is best estimated at 91% risk reduction for HIV, and at 50% risk reduction for bacterial STIs:
- Some STIs (e.g. HPV, herpes simplex virus [HSV]) can be efficiently transmitted through skin-to-skin contact without penetrative sex
- Other STIs (gonorrhoea, syphilis) can be efficiently transmitted through oral sex, during which condoms are much less frequently used
In Aotearoa New Zealand, a range of condoms (size, thickness) are funded, up to a maximum of 60 per script
Non-latex condoms and lubricant are not currently funded and must be purchased by users
Other barrier methods are available on the market but not funded:
- Internal (vaginal) condoms
- Dental dams for protection during oral sex and oral-anal sex (rimming)

In the last decade, HIV pharmacological prophylaxis has become a cornerstone of HIV prevention for people who are considered to be at high risk for HIV acquisition
Pre-exposure prophylaxis (PrEP) is funded in Aotearoa New Zealand for people who meet the PHARMAC criteria
Post-exposure prophylaxis (PEP) is available for people who present within 72 hours after a single high-risk exposure. Eligibility criteria for funded PEP are very limited
PEP may still be recommended in high-risk situations that do not meet the criteria for funding, however the patient would be required to self-fund (cost approximately $80-100). PEP is available through sexual health services or emergency departments – refer to local pathways and guidelines

Prompt diagnosis and treatment of STIs, as well as efficient contact tracing, helps to break the chain of transmission
Treatment as Prevention (TasP), or Test-and-Treat, has become a key factor in pharmacological HIV prevention
People living with HIV who achieve and maintain an undetectable viral load on treatment for more than 6 months, and continue taking treatment as prescribed, are unable to pass on HIV sexually. This is known as U=U (undetectable = untransmittable)
Frequent testing of those at risk, prompt access to HIV care and treatment, and support to achieve and maintain an undetectable viral load, are essential HIV prevention activities