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Sexually transmitted infections (STIs)

Sexually transmitted infections (STIs), also referred to as sexually transmitted diseases (STDs), are infections that are commonly spread by sexual activity. Sometimes these infections can be transmitted through non-sexual route, such as from mother to infant during pregnancy or childbirth, or through blood transfusions or shared needles.

Key facts

  • More than 1 million sexually transmitted infections (STIs) are acquired every day worldwide
  • The majority of STIs have no obvious symptoms or only mild symptoms that may not be recognized as an STI.
  • STIs such as Herpes simplex virus type 2 and syphilis can increase the risk of HIV acquisition.
  • In some cases, STIs can have serious reproductive health consequences beyond the immediate impact of the infection itself (e.g., infertility or mother-to-child transmission)
  • More than 30 different bacteria, viruses and parasites are known to be transmitted through sexual contact. Eight of these pathogens are linked to the greatest incidence of STIs; of these 4 are currently curable: syphilis, gonorrhoea, chlamydia and trichomoniasis. The other 4 are viral infections which are incurable: Hepatitis B, Herpes Simplex virus (HSV or Herpes), HIV, and Human Papillomavirus (HPV).
  • STIs predominantly spread by sexual contact, including vaginal, anal and oral sex. Some STIs can also be transmitted non-sexual route, such as from mother to infant during pregnancy or childbirth, or through blood transfusions or shared needles.

Health risks

  • STIs can have serious consequences beyond the immediate impact of the infection itself.
  • STIs like Herpes and syphilis can increase the risk of HIV acquisition three-fold or more.
  • Mother-to-child transmission of STIs can result in stillbirth, neonatal death, low-birth-weight and prematurity, sepsis, pneumonia, neonatal conjunctivitis, and congenital deformities.
  • HPV infection causes 570 000 cases of cervical cancer and over 300 000 cervical cancer deaths each year.
  • STIs such as gonorrhoea and chlamydia are major causes of pelvic inflammatory disease (PID) and infertility in women.


  • A person can have an STI without having obvious symptoms of disease.
  • Common symptoms of STIs include vaginal discharge, urethral discharge or burning in men, genital ulcers, and abdominal pain.
  • Other symptoms include pain when peeing, lumps or skin growths around the genitals or anus and a rash or itchy genitals or anus.
  • If you think you have any of the above symptoms then do not have sex, including oral sex, without a condom until you have had a check-up.


Effective treatment is currently available for several STIs.

  • Three bacterial STIs (chlamydia, gonorrhoea and syphilis) and one parasitic STI (trichomoniasis) are generally curable with existing, effective single-dose regimens of antibiotics.
  • For Herpes and HIV, the most effective medications available are antivirals that can modulate the course of the disease, though they cannot cure the disease.
  • For hepatitis B, antiviral medications can help to fight the virus and slow damage to the liver.


  • Counselling and behavioral interventions offer primary prevention against STIs including HIV, as well as against unintended pregnancies
  • Correct and consistent use of condoms during vaginal, oral, or anal sex offer one of the most effective methods of protection against STIs, including HIV.
  • Avoid risky sex practices—Sexual acts that tear or break the skin carry a higher risk of STIs.
  • Vaccinations are available that will help prevent hepatitis B and some types of HPV
  • Safe blood transfusion and organ transplantation
  • Use of disposable syringes and sterile and safe instrument

AAs medical advancement is always happening the ITF will periodically update this information, as necessary. You can also keep yourself updated on Sexually Transmitted Infections from the WHO website.