STIs Explained
What's the lowdown?
A sexually transmitted infection is passed from one human being to another through sexual contact. Some have obvious symptoms, but many can be asymptomatic, so it’s important to get tested regularly if you are sexually active.
Anyone can get an STI, whether you have sex with 1 or 100 people. They can be passed on orally, and even if there has been no penetrative sex. STIs like chlamydia and gonorrhoea can be contracted more than once.
There’s no shame in contracting an STI, and regular testing is just another way to look after your health and wellbeing. You can order at-home test kits, or go to your local STI clinic.
The only contraceptives that can protect you from most STIs are barrier methods. The two that provide the best protection are male and female condoms, but there is no guarantee that they will prevent you from getting an STI completely.
Chlamydia is the most common STI across Europe and the United States. Some common symptoms include pain when peeing, unusual discharge, abdominal pain and bleeding after sex. However, a lot of cases are asymptomatic.
Gonorrhoea is the second-most common STI, and is becoming harder to treat with antibiotics. Symptoms include thick, green or yellow discharge, as well as pain during urination. But again, you can be asymptomatic.
HIV is a viral infection that attacks cells that help the body to fight off infection. If left untreated, it can develop into AIDs. Anal sex is 18 times more likely to result in HIV being transmitted than vaginal sex. HIV can affect anyone, but sadly the origins of the virus were, and still are, associated with homophobic discrimination against men who have sex with men. With treatment, the viral load in the blood can lower to a level that makes the disease untransmittable.
Syphilis is a bacterial infection that is passed on through direct contact with sores caused by syphilis that can appear in and around the mouth, genitals, or anus. As well as these sores, symptoms can include a rash on the palms of the hands or soles of the feet; flu-like illness; tiredness; headache or skin growths around the genitals or anus.
Herpes simplex viruses (HS1 and HS2) are viral infections that are passed on when a sore, either on the mouth, genitals or anus, comes into contact with another person’s mouth, genitals or anus. Kissing someone with a cold sore, as well as engaging in oral sex with an infected person, can also infect you with the herpes virus. While herpes cannot be ‘cured’, symptoms come and go. They usually get less severe with each flare up or outbreak. Some people may never have symptoms, and therefore never even know they have the herpes virus. It’s actually more common than you’d think.
Genital warts are caused by two types of human papillomavirus (HPV), but are not linked with cancer. Not everyone who catches HPV will get genital warts. Symptoms of genital warts include painless lumps or itching around the genitals or anus; bleeding from the genitals or anus; and a difference in the direction your pee flows.
Ah, sexually transmitted infections. STIs, STDs, chlamydia, gonorrhoea – just a whisper of one of these words and we’re immediately transported back to flustered school nurses, unripe bananas and paper sachets of assorted condoms.
If you weren’t listening back then (and let’s face it, who was?) it might be time to brush up on your knowledge of STIs – so let’s get into it.
What is an STI?
A sexually transmitted infection (also known as an STD, or sexually transmitted disease) is an infection that is passed from one human being to another through sexual contact. Most STIs are passed along when one person’s genitals come into contact with another person’s genitals or mouth.
Like any infection, once the virus, bacteria or parasite has been passed on, it begins to multiply and have effects on the body. Some of these can be seen in obvious symptoms, but some are hard to detect without a test, so it’s important to be vigilant and get tested regularly if you’re sexually active (more on this later).
Protecting yourself from STIs
Before we dive deep into the world of the most common STIs, let’s look at how we can prevent them in the first place. STIs need physical contact to spread – that means they aren’t airborne and won’t be passed along through clothes.
With that in mind, the only contraceptives that can protect you from most STIs are those which create a barrier between your body and that of the other person. These methods of contraception are, appropriately, called barrier methods, but only two provide good protection against STIs: the female condom and the male condom.
As a contraceptive, the male condom is more effective at preventing pregnancy than the female condom, and is also favoured for protecting against STIs because it’s generally easier to use correctly, so there’s less room for accidents to happen.
Some STIs, like herpes, gonorrhoea and syphilis, can be passed along orally. This happens when one person’s anus or genitals comes into contact with another person’s mouth. If you or your partner have any cuts or sores on your mouth or genitalia, it’s much easier for an STI to be passed on. The male condom can protect against most STIs during oral sex involving the penis, the lesser-known oral condom (also known as a, dare we say it, tonguedom) or dental dam could protect you during oral sex involving the vagina, but research is limited as to how effective these methods are.
There is a common misconception that, during sexual contact, if you don’t have penetrative sex or if the man doesn’t ejaculate (come), an STI can’t be passed on. This is untrue; STIs can also be present in pre-ejaculate (pre-come) in genital fluids, and be passed on through skin to skin contact, so condoms should be used from the moment sexual contact occurs. Similarly, if you’re sharing sex toys with your partner, make sure they’re washed thoroughly before us
Some STIs are easier to catch through anal sex than it is through other forms of sexual contact. This is because the lining of the anus is fragile, and can therefore break easily, leaving it more susceptible to infection. Condoms are your best bet for protecting yourself against STIs during anal sex, and if you use lube during any sexual contact, make sure it’s silicone or water-based. Oil-based lubricants can cause the condom to break. Get Yes water-based lube from Amazon (we earn a small commission from your purchase on this link!)
How soon after unprotected sex should I have an STI check up?
The answer to this is as soon as possible if you have any symptoms which may suggest an STI. However if you have no symptoms and are considering doing a screening test, it is important to think about STI ‘window periods’.
The ‘window period’ is the length of time it can take between catching an infection and when we can be sure it will show up on a test. The window period for the most common STI tests are:
- Chlamydia and Gonorrhoea – 2 weeks
- HIV – 45 days (if tested in a clinic) or 90 days (if self testing)
- Syphilis – 12 weeks
If you are having a check-up it is still worth having the tests even if you are in the ‘window period’ – but you may be advised to repeat the test after the ‘window period’ to be sure.
Now that’s out of the way, let’s look at a few of the most common STIs in more detail.
Chlamydia
Alongside gonorrhoea and HIV, chlamydia is one of the most well-known STIs, and is the most common across Europe and the United States. According to a government report, in 2019 Chlamydia made up 49% of all diagnosed STIs – that’s more than triple that of the second-most common STI, Gonorrhoea.
As with most STIs, it’s more prevalent in younger people, as they are more likely to have multiple sexual partners, but can affect anyone at any age.
Transmission
Chlamydia is spread through sexual contact. Chlamydia can infect the genitals, rectum or throat. To add an extra complication to the mix, you can also get a chlamydial eye infection if semen or vaginal fluid gets in your eye.
Symptoms
Common symptoms of chlamydia in women and people with vaginas include pain when peeing, unusual discharge from the vagina or anus, abdominal pain, bleeding after sex and bleeding between periods.
That being said, you often can’t rely on symptoms to tell you whether you have chlamydia. A whopping 75% of cases in women are asymptomatic (meaning you can have the infections and have no symptoms at all), so it’s hugely important to get tested if you’ve had unprotected sex with a new partner. It can be caught more than once, so even if you have had it and have been treated before, it’s important to be careful and use protection.
If you treat chlamydia quickly, it’s unlikely to cause you any problems. If it is left untreated, however, it can lead to infertility, pelvic inflammatory disease and reactive arthritis – pretty serious stuff.
Testing and Diagnosis
Testing for chlamydia is easy, quick and painless. This can be done at a sexual health clinic, GP surgery or at home. Anyone with a vagina should do a self taken vaginal swab and anyone with a penis should do a urine sample into a cup (2 hours after you last passed urine). If you’ve had anal sex then you can also do a self taken anal swab.
Your sample will then be sent off to a lab, and you should get your results within a week to ten days. If you think you might have been exposed to chlamydia (i.e. if you are being tested because you know your partner has chlamydia, as opposed to just having regular screening) you might be asked to start treatment before your results come in.
The NHS recommends that all under-25s should get tested at least once a year, and every time they change sexual partners. If you’re under 25, you can get tested by the National Chlamydia Screening Programme (NCSP) at a pharmacy, contraception clinic or at some colleges.
You can also get home-testing kits through the NHS or by buying them online. Through the post, you will be sent a urine pot to pee in, or instructions about how to do a self-swab, which you can then send back to the laboratory by following the instructions on the specific kit you buy. It’s important that you buy your kit from a reputable retailer, and you should read the NHS guidance about self-testing before you order.
Treatment
Chlamydia is treated using antibiotics. Your doctor or nurse will usually prescribe you doxycycline, which you take twice a day for a week. 95% of people will be cured of chlamydia if they take their antibiotics as instructed.
How long until chlamydia goes away?
With treatment, chlamydia should clear up within 1-2 weeks. You shouldn’t have any sexual contact with another person during this time, as you could still pass it on to your partner. You also shouldn’t have sex with your partner – including vaginal, oral or anal sex, even with a condom – until both you and your partner (or partners) have completed treatment, otherwise you risk reinfection!
Gonorrhoea
Gonorrhoea, otherwise known as ‘the clap’, is becoming more difficult to treat effectively with antibiotics – it’s the second-most common STI, making up 15% of all new diagnoses in 2019.
Transmission
Like all STIs, gonorrhoea is passed on through sexual contact. This means that if you have anal, oral or vaginal sex with an infected person, you could catch it. Similarly to chlamydia it can infect the genitals, rectum, and less commonly the throat or eye. It can be caught more than once, so even if you have had it and have been treated before, it’s important to be careful and use protection.
Symptoms
Gonorrhoea is infamous for its unpleasant symptoms – thick, green or yellow discharge from the vagina or penis, as well as pain during urination. Women and people with vaginas can also experience bleeding between periods and pelvic pain.
Like chlamydia, however, gonorrhoea can have no symptoms in a large number of cases. Around 10% of men and 50% of women will experience no symptoms, so it’s really important to get tested if you think you might have had sexual contact with an infected person, even if you feel totally fine.
If you leave gonorrhoea untreated, it can lead to serious health problems that are difficult to treat, such as Pelvic Inflammatory Disease. So if you are diagnosed, it’s important that you start treatment as soon as you can.
Testing and Diagnosis
As with chlamydia, testing for gonorrhoea in people with no symptoms can be done with self taken swabs or a urine sample if you have a penis. If you have symptoms such as pain, vaginal discharge or discharge from the penis you need to attend a sexual health clinic for an examination. This will involve a swab of the affected area which can be looked at under a microscope to identify the gonorrhoea bacteria.
You can get tested at your GP surgery, a sexual health clinic or from a private healthcare provider. You can buy a test online or from a pharmacy, but the NHS recommends you go to a specialised clinic, as at-home tests aren’t always consistently accurate. If you do decide to self-test, be sure that the retailer is reputable, and read the NHS guidance on self-testing before you buy anything.
Treatment
Gonorrhoea is treated with antibiotics. Usually, a single antibiotic injection is given. Two weeks after you are treated, you should get tested again to check that the infection has gone. This is important as there are increasingly cases of gonorrhoea resistant to standard treatment.
You should refrain from sexual contact with anybody until you test negative for Gonorrhoea after treatment. You also shouldn’t have sex with your partner until both you and your partner (or partners) have completed treatment.
How long until gonorrhoea goes away?
With treatment, symptoms of gonorrhoea should go away within a few days. If you have pain in your pelvis or abdomen, this might take a further two weeks to disappear completely and you should be offered a follow up appointment to check this with your doctor or nurse.
Trichomoniasis
Trichomoniasis is caused by a parasite that only lives in the human genital tract (not where we’d pick as our dream home location, but each to their own). It isn’t super common, with only 6000 cases reported each year, but is still something to watch out for.
Transmission
Trichomoniasis is transmitted through sexual contact with the penis, vagina or urethra. It is not thought that you can pass trichomoniasis on through oral or anal sex. It can be caught more than once, so even if you have had it and have been treated before, it’s important to be careful and use protection.
Symptoms
Over half the people infected with trichomoniasis will have no symptoms at all. In women, symptoms might include discharge that is abnormal in quantity and consistency or has a fishy smell, soreness around the vagina, and pain when peeing or having sex.
In men, trichomoniasis rarely causes symptoms but they can include discharge from the end of the penis, an increased need to urinate, burning when peeing and a soreness, swelling or itchiness around the head of the penis.
Testing and Diagnosis
Trichomonas is not tested for in routine STI screening for people who have no symptoms. However if you have symptoms such as vaginal discharge or pain on passing urine and you attend a sexual health clinic, your doctor or nurse will usually conduct an examination, and test for trichomonas. The symptoms of trichomoniasis are similar to those of other STIs, so it can be hard to diagnose.
Your doctor or nurse might also take a swab of the inside of your vagina (or penis, if you’ve got one). Men can also give a urine sample. The sample will then be sent to a lab, and it may take several days for a result to come through. In sexual health clinics a diagnosis can be made looking at a sample from a swab under a microscope.
If your doctor or nurse strongly thinks you have trichomoniasis, you may be advised to begin treatment before your lab results come back.
Treatment
As with most STIs, trichomoniasis is treated with antibiotics. Metronidazole is most likely to be prescribed, to be taken twice a day for five to seven days. You might sometimes be advised to take the full course all at once, but this can increase the side effects of the medicine and isn’t recommended if you are pregnant or breastfeeding.
How long until trichomoniasis goes away
Trichomoniasis should clear up within a week of treatment. You shouldn’t have sex until at least a week after your treatment has begun, and until both you and your partner or partners have completed treatment.
HIV
HIV (human immunodeficiency virus) is a viral infection that is passed on through sexual contact. The virus attacks the cells that help the body to fight off infection, and if it is left untreated, it can lead to late HIV, also known as acquired immunodeficiency syndrome, or AIDS.
HIV wasn’t actually discovered until 1981, and quickly became an epidemic. Due to the virus disproportionately affecting men who have sex with men and the Black African population, the origins of HIV are rooted in discrimination and stigma, much of which is sadly still present today. The fact is that HIV can affect anyone! According to research, anal sex is 18 times more likely to result in HIV being transmitted than vaginal sex. This is because the lining of the anus is fragile, and can therefore break easily, leaving it more susceptible to infection.
A campaign called ‘Undetectable = Untransmittable’ or ‘U=U’ aims to raise awareness about the ways in which the transmission of HIV can be stopped. If a person receives treatment, it can lower the viral load in the blood to a level that makes the disease untransmittable. Spreading this message is important and helps tackle the stigma around HIV and barriers to testing.
Anyone can get HIV, and while rates in the UK are consistently declining, protecting yourself is just as important as it ever was.
Transmission
Most cases of HIV are passed on through unprotected (without a condom) vaginal or anal sex. It is possible to contract HIV from oral sex, but this is very rare. Your risk of contracting or passing on HIV from oral sex is higher if you have cuts, sores or ulcers in your mouth or other STIs as the same time.
The more recently a person has been infected with HIV, the higher the chances they will pass it on. This is because, at the beginning of the infection, there is a large quantity of the virus within the body.
Symptoms
Most people infected with HIV will experience a period of illness within 2-6 weeks of becoming infected. This illness will feel like the flu, and symptoms include a sore throat, a fever or a rash on the body. After a week or two, these symptoms should disappear, and you might not have any other HIV symptoms for many years.
During this time, the virus continues to attack the body’s immune system. This could continue for up to a decade, during which time you might feel and seem perfectly well. At some point, the immune system will become badly damaged and more severe symptoms will occur, such as weight loss, diarrhoea, infection and extreme illness.
Testing and Diagnosis
If you think you have been exposed to HIV, it is important that you get tested as soon as possible. HIV testing is always free on the NHS, and can be done at home, at a sexual health clinic, at private clinics or at some GP surgeries.
A HIV test is conducted using a sample of your blood or saliva. The most reliable test is a blood test, where a sample of your blood will be sent to a laboratory for analysis. You can also give a sample of your saliva or a small drop of blood from the end of your finger. These tests can be conducted at a clinic or at home, and result times vary depending on the method. Tests may also need to be repeated. You can see all the testing options on the NHS website.
Treatment
If you think you have been exposed to HIV within the last 72 hours, you can take a post-exposure prophylaxis (PEP) drug, which could prevent you from becoming infected. This is available from sexual health clinics or emergency departments. For groups at high risk of exposure, PreP (pre exposure prophylaxis) is also an option. This is where someone who is HIV negative can take medicine before they have sex to reduce the risk of acquiring HIV.
There is currently no cure for HIV, but treatments are available that can allow an infected person to live a full and healthy life. If you are diagnosed with HIV, your healthcare provider will want to conduct blood tests to monitor the amount of the virus in your body and the effects it has already had on your immune system. Once these have been established, treatment can begin.
HIV is treated using Antiretroviral medicine. These medicines stop the virus from multiplying in your body, giving your immune system time to repair itself and stopping any further damage from occurring. The HIV virus adapts and changes quickly, so people often have their treatment changed or combined from time to time to ensure it is still effective. Every HIV patient is different in how their body responds to treatment, so your exact combination will be personal to you.
You can see a full explanation of HIV treatment on the NHS website.
How long until HIV goes away?
There is currently no cure for HIV. Thanks to advances in medicine, however, people can now live full and normal lives with HIV if they seek treatment.
Syphilis
Syphilis is an STI that is passed on through direct sexual contact.
It is not clear exactly when or where syphilis originated from, but there have been outbreaks throughout history, often with each country blaming another for causing the epidemic.
Cases of syphilis have actually almost tripled over the last decade, and most often occur in men (with the highest rates among men who have sex with men), who made up 90% of the cases in 2019.
Transmission
Syphilis is a bacterial infection that is passed on through direct contact with a ‘chancre’, a sore caused by syphilis. These sores appear in and around the mouth, genitals, or anus, and the disease is therefore passed on through any kind of sexual activity.
Syphilis can be caught more than once, so even if you have had it and have been treated before, it’s important to be careful and use protection.
Symptoms
Syphilis symptoms aren’t always obvious, and some people have no symptoms at all. If you do have symptoms, these might disappear, but that does not mean that you are no longer infected. Unless you get treatment, syphilis will not go away.
Symptoms of syphilis include ulcers in or around the genitals, anus or mouth, which are usually small and painless and may not be noticed at the time; followed by a rash on the palms of the hands or soles of the feet; flu-like illness; tiredness; headache or skin growths around the vulva or anus.
If syphilis is not treated, it can spread to other parts of your body, such as your brain. This can cause serious problems and be much harder to treat, so it is important to get tested and treated as soon as possible if you believe you have been exposed.
Testing and Diagnosis
The best place to have a syphilis test is a sexual health clinic, but you can go to your GP first if you prefer. They may refer you to a sexual health clinic if they aren’t able to test you themselves.
A syphilis test usually involves a physical examination, a blood test and a swab of any sores you might have. If you don’t have any physical symptoms, or think you might have been exposed quite recently, a repeat blood test may be recommended a few weeks later to check for an infection that was missed.
Results can take up to two weeks to come back, but some may be available the same day.
Treatment
For most people, a short course of antibiotics will cure syphilis. The way these antibiotics are given to you depends on how long you have had syphilis for.
If you have had syphilis for less than two years, you will be offered either a single injection of penicillin in your buttocks, or a 10-14 day course of antibiotics. If you have had syphilis for more than two years, you will be offered either an injection of penicillin into your buttocks every week for three weeks, or a month-long course of antibiotics.
If syphilis has progressed to the brain, you will usually be offered penicillin injections into the buttocks or veins every day for two weeks, or a month-long course of antibiotics.
You should not have sex or sexual contact with another person for at least two weeks after your treatment finishes – this is because the infection could still be present and you could pass it on.
How long until syphilis goes away?
With treatment, symptoms of syphilis should clear up within three to six weeks. It is vital that you complete your course of antibiotics, even if you begin to feel better sooner. If you don’t, the bacteria could still be present and symptoms could come back. You could also reduce the chances of the treatment working again for you and for others.
Herpes
The Herpes simplex viruses (HS1 and HS2) are viral infections that are passed from person to person via direct contact with the anus, genitals or mouth.
The majority of herpes cases occur in heterosexual people aged 15-24 years.
Transmission
Herpes is passed on when a sore, either on the mouth, genitals or anus, comes into contact with another person’s mouth, genitals or anus.
You’ve probably heard that cold sores are herpes, and that giving oral sex when you have a cold sore can infect someone with genital herpes. This is true. The herpes virus from sores on the mouth, genitals or anus can be passed on to any of these parts of the body, so kissing someone with a cold sore, as well as engaging in oral sex with an infected person, can also infect you with virus.
Herpes symptoms can flare up and die down, and while you are more likely to catch herpes from someone with sores, you can still get it if they have no current symptoms.
Symptoms
Herpes symptoms can take a long time to appear. Symptoms of herpes generally occur in the genital area or mouth. These are pain or itching; red bumps or blisters; ulcers and scabs. In the early days after infection, you may also experience flu-like symptoms.
Testing and Diagnosis
You can only be tested for herpes if you have visible sores or blisters. A doctor or nurse will swab the fluid from one of your sores for testing. They will also ask you about your sexual history and other symptoms. You should go to a sexual health clinic for a herpes test, as they are more likely to have the kits and resources. You can go to your GP if you prefer, but they may refer you to a sexual health clinic.
Treatment
There is no cure for oral or genital herpes. Treatments target the symptoms of the infection, and include medication to prevent blisters from worsening or cream to target the pain.
Once you are infected with herpes, you are infected for life. Symptoms, however, come and go, and usually get less severe with each flare up or outbreak. Some people may never have symptoms, and therefore never know they have the herpes virus. Most people who do have symptoms experience fewer flare ups as time goes by.
The NHS website has some useful information about dealing with outbreaks by yourself.
How long until herpes goes away?
A herpes outbreak generally lasts one to two weeks, with the first time usually being the longest, and each subsequent outbreak usually getting shorter or less severe. If you have herpes, you will never be cured, but your symptoms should improve over time.
It is important to tell any potential sexual partner if you have herpes and avoid having sexual contact if you have visible sores.
Genital warts
Genital warts are often confused with herpes, but they’re actually caused by an entirely different virus called human papillomavirus (HPV). Ring a bell? You might have had a HPV vaccine at school to protect you against cervical cancer. Two types of HPV cause genital warts, which is not linked to any type of cancer.
The HPV vaccine also helps protect against genital warts. There are over 100 types of HPV, and almost all of us will be infected with at least one at some point in our lives.
Transmission
HPV is easy to catch, and can be passed on through genital contact (not necessarily penetrative sex), oral sex or sharing sex toys. Not everyone who catches HPV will get genital warts, so you might not know you have HPV. This is why HPV can be unknowingly spread between partners.
Symptoms
Symptoms of genital warts include painless lumps around the vagina, penis or anus; bleeding from the genitals or anus; itching around the vagina, penis or anus; and a difference in the way your pee flows, like if it begins to flow sideways, or in a different direction to usual.
You may not have any symptoms at all. If you have visible genital warts, they can come and go.
Testing and Diagnosis
You should go to a sexual health clinic to get examined for genital warts. You can go to your GP, but they will usually refer you to a specialist clinic.
The doctor or nurse at the clinic will usually talk to you about your sexual history and symptoms, and will examine you for warts, either externally or inside the vagina, urethra or anus, depending on whether you have visible lumps or not. In some cases, your doctor or nurse may take a sample (biopsy) of a wart to test whether HPV is present or not.
If you have no visible warts, your doctor or nurse will not be able to tell you whether you have the HPV virus that causes genital warts or not.
Treatment
Similar to warts on the hands, treatment for genital warts focuses on removing the warts themselves as opposed to clearing up the infection. A cream can be applied either at home or at a clinic, which should help to reduce or remove the warts. You can also have your warts removed with a laser, incision or freezing treatment. This can be painful.
The treatment you receive will depend on the appearance and location of your warts. Treatment can take a long time, and the warts may come back. For some people, the body will fight the virus over time and symptoms will lessen or disappear.
How long until genital warts go away?
There is no cure for genital warts. Treatments focus on removing individual warts or clusters of warts, as opposed to curing the virus itself. With treatment, warts could take between several weeks to several months to reduce or disappear.
We’ve covered the most common STIs here, but there are others that you could come into contact with. For all diseases, prevention is always better than cure, so be sure to protect yourself by using condoms, having regular screening and testing in new relationships. Most STIs can be easily treated, so don’t be scared of having a test and finding you do have an STI. It’s important to remember if you are diagnosed with an STI, your current and recent sexual partners should be tested and treated as well – sexual health clinics will help you to do this confidentially. The NHS has some brilliant resources but if you’re unsure about your next steps speak to your GP or contact your local sexual health clinic.
Our medical review process
This article has been medically reviewed for factual and up to date information by a Lowdown doctor.