Exploring Sexual Health: The Basics of Sexually Transmitted Infections (STIs)

Couple in bed STIs STDs

What’s in a name?

The term ‘sexually transmitted infections (STIs)’ are often used interchangeably with ‘sexually transmitted diseases (STDs)’. However, there have been an increasing use of the term STIs rather than STDs. This is as ‘infection’ refers to an invasion of a body by microorganisms such as bacteria, viruses or parasites. On the other hand, ‘diseases’ means that the invasion had impaired the normal functioning of the body, resulting in apparent signs and symptoms, which may not necessarily be true in some cases. Moreover, a study has shown that the use of STIs were perceived to be slightly less stigmatising compared to STDs, and the word ‘infection’ also puts an emphasis on prevention, rather than ameliorating a disease. However, it is still generally acceptable to use either, as the use of either terms have little to no impact on the prevention strategies or the clinical procedures carried out by prevention programmes and health care providers. In this article, the term ‘STIs’ is used for consistency.

What are STIs?

STIs are common and preventable causes of death and serious complications. Everyday, more than 1 million people worldwide acquire STIs. There are many types of STIs and some can have a profound impact on one’s sexual and reproductive health, especially if left untreated. STIs can be caused by bacteria, viruses or parasites, and below are some examples of STI:

  • Gonorrhea
  • Syphilis
  • Chlamydia
  • Trichomoniasis
  • Human papillomavirus (HPV)
  • Hepatitis B
  • Human immunodeficiency virus (HIV)

How does one get an STI?

STIs are mainly spread via sexual contact, including vaginal, anal and oral sex. They can also be transmitted through intimate physical contact. Some people may also get STIs from infected blood or blood products. Mother to child transmission can also take place during pregnancy and childbirth.

Who are at risk of getting infected?

Generally, anyone who is sexually active faces some risks to getting exposed and infected by an STI. However, there are certain populations who have additional risk factors.

Those who had vaginal or anal sex with an infected partner have a higher risk of getting STIs. The use of latex condoms can reduce, but not completely eradicate, the risk of transmitting STIs. The inconsistent and improper use of condoms can also put one at a higher risk of getting infected.

Those with multiple sexual partners are also at a higher risk. This is as the more people one has sexual contact with, the greater the risk of being exposed to an STI. This also applies to those who had monogamous consecutive relationships.

It was also found that men with have sex with men, commonly termed as MSM, are disproportionately affected by syphilis and HIV. Additionally, there are increasing rates of syphilis, gonorrhea and chlamydia in the US and Europe, and such STIs were found to disproportionately affect MSM with HIV.

The prevalence of STIs in adolescents were found to be high, with approximately half of the estimated 19 million STI cases each year in the US found to occur in young people aged 15 to 24 years old.

Those with a history of STIs are at a greater risk as it is easier for them to get reinfected.

Symptoms of STIs in women

How to know if one has STI?

STIs can have a range of signs and symptoms, where some may even present with no symptoms. Depending on the organism that caused the infection, signs and symptoms may appear a few days or many years after exposure.

Some signs and symptoms of STIs includes:

  • Sores or bumps on the genitals, mouth or rectal area
  • Burning sensation or pain during urination
  • Abnormal vaginal discharge
  • Discharge from the penis
  • Pain during sexual intercourse
  • Fever
  • Rash over the trunk, hands or feet

It should be noted that these signs and symptoms may not be specific to STIs, having such signs and symptoms does not necessarily mean that one has been infected. However, it is recommended that upon having such symptoms, you should consult a doctor, especially if you are sexually active and suspect that you may have been exposed to an STI.

As some STIs presents with no signs and symptoms, or take years before the symptoms appear, it is also important to get tested for STIs so as to identify and treat infected persons before complications develop, as well as to prevent further transmission and reinfections.

If you would like to learn more about STIs, please do speak with our doctors as they are able to provide you with more information. 




Lederer AM, Laing EE. What's in a Name? Perceptions of the Terms Sexually Transmitted Disease and Sexually Transmitted Infection Among Late Adolescents. Sex Transm Dis. 2017 Nov;44(11):707-711.

Handsfield HH, Rietmeijer CA. STI Versus STD. Sex Transm Dis. 2017;44(11):712–713. 

https://www-uptodate-com/contents/prevention-of-sexually-transmitted-infections?search=STI&source=search_result&selectedTitle=3~150&usage_type=default&display_rank=3" \l "H1