Sexually Transmitted Infections (STIs) are infections generally acquired through sexual contact. They may be caused by bacteria, viruses or parasites that can be passed from person to person through blood, semen, vaginal or other bodily fluids. STIs don't always cause symptoms, and it is possible to contract STIs from people who seem perfectly healthy and are unaware they have an infection.
STIs may be transmitted through a number of ways:
- During unprotected sexual intercourse (vaginal, anal or oral) with an infected partner.
- Skin to skin contact.
- Saliva when kissing.
- Through the sharing of injection needles and other piercing instruments used for tattooing, or acupuncture that are contaminated with an STI.
- From an infected mother to her baby during pregnancy, at birth, or through breastfeeding.
- By receiving infected blood and blood products (e.g. organs, plasma).
Are drug users or men who have sex with men more likely to get infected with STIs than other people?
Anyone who participates in high-risk behaviours such as unprotected sex, casual/commercial sex, or sex with multiple partners is at risk of becoming infected with an STI. STIs do not differentiate, regardless of whom one participates in sexual activity with.
Abstinence: The only 100% effective way to avoid an STI is to not have vaginal, anal, or oral sex.
If you are sexually active, you can reduce your chances of getting an STI by practising the following:
If you are sexually active, you can reduce your chances of getting an STI by practising the following:
- Reduce your number of sexual partners: Do not engage in casual sex. If you are unsure of your STI status, do go for an STI screening.
- Mutual monogamy: Be faithful to your partner and be honest with each other about your sexual history.
- Use condoms: Use a latex condom consistently and correctly every single time from the start to the end of the sexual act. Condoms should be used for vaginal, anal and oral sex as they are highly effective in reducing STI transmission.
- Avoid substance abuse: Limit the consumption of alcohol and avoid drugs before and during sex. Substance use can affect your judgement, causing you to engage in risky sexual behaviour.
- Get vaccinated: Some types of STIs such as Human Papillomavirus (HPV), Hepatitis B and Mpox can be prevented with vaccinations. Have an open conversation with your doctor to determine if you should be vaccinated and/or get tested for STIs.
After sexual intercourse, can someone prevent being infected with an STI if they wash their vagina, penis or rectum?
While washing before and after sexual intercourse is a good hygiene practice, it cannot prevent the spread of bacteria or viruses that cause STIs. The best way to prevent the spread of STIs is to consistently use a condom, be faithful to one partner and to avoid casual sex. Testing regularly for STIs if you think you are at risk or before engaging in sex with a new partner is recommended.
Can a person be immunised against STIs? Does a person develop immunity to an STI once he or she is cured of the infection?
Vaccines are available to prevent some STIs such as Hepatitis B infection, HPV and Mpox. With the exception of vaccine preventable infections, a person may be re-infected with an STI despite having been previously treated for it.
Can a person take antibiotics before sex to prevent STIs?
Current evidence does not support the use of oral antibiotics to prevent bacterial STIs due to the risk of promoting antimicrobial resistance, which can make the bacteria harder to treat in the future. This is known as antibiotic resistance, and STIs caused by resistant organisms are more difficult to cure. The best prevention against STI before sex is the consistent and correct use of a latex condom. There are however specific medications that can be taken before or after exposure to HIV. This is known as pre and post exposure prophylaxis. However, these products effectively prevent HIV transmission but not the other types of STIs.
A person infected with an STI could either not notice any symptoms (asymptomatic), or experience uncomfortable and obvious symptoms. If you or your partner is at risk of exposure to STIs, you should get regular sexual health screening. This can help prevent any long-term complications from exposure to STIs, prevent the STI from spreading to others, and allow for treatment as early as possible.
The following symptoms may indicate an STI infection:
- Genital discharge
- Painful urination
- Itch or rash
- Blisters, ulcers, lumps or growths
- Fatigue
- Weight loss
- Fever
- Night sweats
- Persistent diarrhoea
- Swollen neck glands
- Lowered resistance to infections
You should get tested if:
- You have engaged in any sexually risky behaviour in the past - such as having multiple or casual sexual partners, not using condoms consistently, or have engaged the services of commercial sex workers.
- You are unsure of your partner's sexual history.
- You had yourself pierced or tattooed by an unhygienic or unlicensed parlour.
- You had a blood transfusion or an operation performed overseas, where blood testing regulatory requirements may not be stringent.
Getting screened for STIs is the crucial first step to knowing your STI status. Knowing your status enables you to receive treatment early and prevent others from being infected.
Many GP clinics offer routine STI screening services, with some medical clinics offering rapid HIV testing as well. You can also get yourself tested for STIs or HIV/AIDS at polyclinics, private clinics and hospitals. The DSC clinic is the subsidised specialist outpatient clinic for the diagnosis, treatment and control of STI infections in Singapore.
If you prefer anonymity, there are clinics in Singapore that offer anonymous HIV rapid tests. No identifiable information will be taken during the anonymous testing. More information about HIV testing can be found here.
Regardless of where you get tested at, be assured that the identities of people who go for STI/HIV screening and those found to be HIV-positive are kept strictly confidential.
The doctor providing your consultation may ask questions regarding your sexual health history, to determine the type of tests you may need. These may include:
- Blood tests
- Swab/smear tests from the vagina, cervix, rectum, penis, mouth or throat
- Urine tests
The typical turnaround time for STI test results are as follows:
| Test | Turnaround Time |
| HIV Rapid Tests | 30 minutes *A follow up or confirmatory test is usually required if rapid tests are reactive |
| Microscopic Examinations (Urethral Smear, Scraping, Full Smear, and Urine FEME) | 30 to 60 minutes |
| Syphilis (RPR) | 1 hour |
| Syphilis (TPHA) | 1 to 3 days |
| Chlamydia & Gonorrhoea PCR Hepatitis B Antigen Hepatitis B Antibody HIV Screening Test (ELISA) Syphilis Total Ab EIA | 1 to 2 weeks |
| Gonorrhoea Culture Hepatitis A IgG Antibody Hepatitis C Antibody Herpes Simplex Type 1 IgG Antibody Herpes Simplex Type 2 IgG Antibody Herpes Simplex Virus PCR Culture – Pyogenic Organisms | 2 weeks |
| ThinPrep Pap Smear | 3 weeks |
There are many types of STIs; each can impact your short and long-term health as well as fertility in different ways. Treatment for STIs varies for different types of infections and may include specific types of antibiotics or antiviral medications. It is important to be treated by a medical doctor with prescribed medications as early as possible to avoid passing on the infection to your partner and to reduce potential health complications for yourself.
Some of the common STIs are listed below, click on them to find out more
Are all STIs curable? Why do I need to seek early treatment for STIs?
Bacterial STIs are often curable if treated early, especially if the bacteria causing the STI has not become resistant to antibiotics. Early treatment of an STI may prevent transmission to others and reduce the risk of complications. Many viral STIs however are not curable but can be managed well with treatment.
Incubation period refers to the amount of time after being exposed to an STI before one starts experiencing symptoms or become infectious to others. It is highly dependent on the type of STI one has been infected with. The incubation period may be anywhere from a few days to a few months later. For HIV, one may not experience noticeable symptoms for 5 to 8 years or more, and may be unaware that he or she has been infected until a test has been done.
Infectious period refers to the period where an infected person may transmit the infection to others. Similar to incubation period, it depends on the type of STI one has been infected with. Infection can spread from someone who is asymptomatic (no symptoms) or from an infected person who has yet to recover.
Below is a table showing the incubation period for some of the STIs and when to get tested:
| Types of STI | Time frame to get tested after exposure | For positive tests, there is a need to be retested after treatment? |
| Chlamydia | 24 hours to 5 days | Retest after 2 weeks to ensure recovery |
| Gonorrhoea | 2 to 6 days | Retest after 2 weeks to ensure recovery |
| Syphilis | 3 to 6 weeks | Retest after 3 months to ensure recovery |
| Hepatitis A (HAV) | 2 to 7 weeks (average 4 weeks) | Retest is not required |
| Hepatitis B (HBV) | 6 weeks | Retest is not required |
| Hepatitis C (HCV) | 8 to 9 weeks | Retest after 3 months to confirm test results |
| Oral Herpes (HSV-1/Herpes I) | 4 to 6 weeks | Retest frequently if you have unprotected oral sex and are in contact with saliva or semen |
| Genital Herpes (HSV-2/Herpes II) | 4 to 6 weeks | Retest after 3 months to confirm test results |
| HIV Gen 3 rapid test | 4 to 6 weeks | Retest after 3 months if earlier test was negative |
| HIV Gen 4 rapid test | 14 days | Retest after 3 months if earlier test was negative |
