Sexually transmitted infections

Also called sexually transmitted disease (STDs)

Sexually transmitted infections (STIs) are infections that are passed from one person to another through unprotected sex or genital contact.

STIs are so common that anyone who has ever had sex could get one. Whether you get one is not about you being good, bad, clean or dirty, but it’s about being normal and sexually active. You can reduce your chances of getting an STI by using condoms (pukoro ure) with all new partners and having regular sexual health checks.

There are many different types of STIs. Read more about the most common STIs.

How safe is sex?

Any sexual activity exposes you or your partner to STIs. The risks of getting STIs vary with different sexual activities.

  • Kissing exposes you and your partner to a few STIs such as herpes and hepatitis. Avoid kissing when sores or cuts are present in and around your mouth.
  • Fingering is when someone inserts one or more fingers into their partner's vagina or anus. It's not common for fingering to spread STIs, but there are still risks. If there are any cuts or sores on your fingers, no matter how small, the risk of passing on or getting HIV or other blood-borne infections such as hepatitis B or hepatitis C increases. You can lower your risk by wearing surgical gloves.
  • Skin-to-skin touching exposes you and your partner to several STIs such as syphilis, genital herpes, HPV, pubic lice and scabies.
  • Oral sex exposes you and your partner to many STIs. Giving and getting oral sex puts you at risk of getting chlamydia, gonorrhoea, syphilis, genital herpes, hepatitis B and HIV.
  • Vaginal sex exposes you and your partner to all the STIs. 
  • Anal sex exposes you and your partner to most of the STIs, such as chlamydia, gonorrhoea, syphilis, genital herpes, HPV, hepatitis B, HIV, pubic lice and scabies.
  • Sex toys – any object used in sex can be called a sex toy, whether it's designed for this use or not. It's important to keep sex toys clean. If you're sharing sex toys, make sure you wash them between each use and always use a new condom each time. Sharing sex toys has risks, including getting and passing on infections such as chlamydia, syphilis and herpes. If there are any cuts or sores around your vagina, anus or penis and there's blood, there's an increased risk of passing on hepatitis B, hepatitis C and HIV.

If you choose to have vaginal, oral or anal sex, always use condoms. They reduce the risk of spreading STIs. 

Sexual health self-assessment

How much do you know about having a safer sex life? Take the safer sex test and find out how much you know about contraception and sexually transmitted infections.

What are the risk factors for STIs?

Anyone who has sex or engages in sexual activity is at risk of getting an STI, but you are at higher risk of getting STIs if:

  • you have more than one sexual partner
  • your partner has or has had more than one sexual partner
  • you have sex with someone who has an STI
  • you've had STIs in the past.

Exposure to infected needles and syringes, by you or your partner using intravenous drugs (injected into a vein), or through tattooing or piercing equipment, can also put you at risk of getting STIs such as hepatitis B and HIV. 

Adolescents have a higher risk of getting an STI than adults.

What are the risks of not treating an STI?

STIs will not go away by themselves so if you get one you need to get it treated. If left untreated some STIs can be a serious health risk and can cause other conditions such as:

  • pain and inflammation in your genital area
  • pelvic inflammatory disease (PID) in women and epididymitis in men
  • infertility
  • cancers of your reproductive system.

What if I am pregnant and have an STI?

Having an STI during pregnancy can harm your baby. Gonorrhea and chlamydia both can cause health problems in the infant ranging from eye infections to pneumonia. Syphilis may cause miscarriage or stillbirth. HIV infection can occur in a baby.

If you are pregnant and you or your partner have had – or may have – an STI, it's important to tell your healthcare provider. Your baby may be at risk. Tests for some STIs are offered routinely during prenatal care. It is best to treat the STI early to decrease the chances that your baby also will contract the infection. You and your partner both may have to be treated.

What are the symptoms of STI?

Not all STIs have symptoms, and it is possible to have an STI without even knowing as sometimes the symptoms are so small, especially in the early stages. Because there are many different STIs, the symptoms may vary. Some of the general symptoms include:

  • unusual discharge from your penis or vagina
  • itch or rash on or around your genitals
  • lumps, blisters or sores on or around your genitals
  • pain in your genital area or groin
  • pain in your penis or vagina when having sexual intercourse
  • pain or a burning sensation when passing urine (peeing).

How to get tested for an STI?

You can be tested for STIs at a sexual health clinic, family planning clinic or at your GP surgery. You should get tested:

  • if you or your partner have any symptoms
  • if the condom breaks or if you have sex without one
  • before you have sex with a new partner
  • if you or your partner have been sexually active and have not been tested
  • if you know your current or past partner has or has had an STI
  • if you or your partner have shared needles for drugs, tattooing or piercing.   

Telling your partner

If you have an STI, it is important to tell your partner, so they can be tested and treated as well. This reduces the spread of the STI and lessens your chance of getting it. It's best to tell your partner as soon as possible after finding out that you have an STI, or before having sex with an untreated partner. Some people may find the experience of telling their partner awkward and difficult. If so, talk to your doctor or nurse, or contact your local sexual health clinic, or family planning clinic for guidance.

Learn more

Just the facts on STIs  Just the Facts, New Zealand
What are the symptoms of STIs Just the Facts, New Zealand
Sexually transmissible infections Family Planning, New Zealand
Fact sheets Auckland Sexual Health Service


  1. Sexually transmitted infections, Summary of guidelines New Zealand Sexual Health Society, 2017