Chlamydia is the most common sexually transmitted infection (STI) or sexually transmitted disease (STD) in the UK with more than 200.000 new cases reported to the NHS every year. It can affect both sexes and usually manifests in the genitals, anus, throat or eyes. As all STIs, chlamydia too is spread to unprotected sex. As a bacterial STI, chlamydia can be successfully treated with antibiotic medicine.

In this article, we will answer the most commonly asked questions about this STD.

What’s on this page?

What is chlamydia?

Chlamydia is a bacterial STI caused by the bacteria from the strain Chlamydia trachomatis. While asymptomatic in a majority of cases, some of those affected who experience symptoms will begin notice them in the first couple of weeks following infection. This condition can be rather unpleasant, but the major risk associated with it lies in the possibility of further complications.

How common is chlamydia?

With more than 200.000 cases being reported every year within the UK, chlamydia is without doubt the most common STI in the UK. However, in terms of the global population, chlamydia doesn’t take the first place which is, on the scale of the world, reserved for HPV (genital warts). Studies estimate that around 2% of global population under the age of 25 is affected by this condition. This group comprises majority of chlamydia cases in the world – as much as 70%.

Is chlamydia more common in men or women?

Chlamydia is more commonly diagnosed in women, as compared to men. However, many medical experts note that the official statistics might be somewhat distorted by the fact that women are significantly more likely to undergo regular STI tests as compared to men. This means that the number of diagnosed cases probably doesn’t correspond perfectly to the number of actual cases. Still, even when this factor is taken into account, it would seem that chlamydia is more prevalent in women and the greater rate of discovery of the condition cannot explain the disproportionate prevalence on its own. For example, in 2015, Public Health England had data on 114.509 female cases and 83.794 male cases.1

Is chlamydia a bacterial or viral infection?

Chlamydia is a bacterial STI, caused by the bacterium Chlamydia trachomatis – one specific strain from the wider Chlamydia family of microscopic organisms.

How many days before chlamydia symptoms appear?

A significant number of chlamydia cases can remain completely asymptomatic, with around five in every ten men affected and eight in every ten women affected not showing any signs of symptoms of infection. This makes this condition especially difficult to diagnose without timely and regular STI testing.

Those people who do experience chlamydia symptoms, it might take a couple of weeks from the moment of infection to the moment when they are noticeable.

What are the symptoms of chlamydia?

The symptoms of chlamydia can vary among sexes, but also based on which part of the body is affected. In case of genital chlamydia, the most common signs and symptoms include:

  • Painful urination
  • Changes in vaginal discharge
  • Penile discharge
  • Pain and discomfort in the lower abdomen (more common in women)
  • Vaginal bleeding during or after sex
  • More intensive periods
  • Bleedings between periods
  • Pain in the testicles
  • Swelling of one or both testicles

In those cases where the condition is rectal, the symptoms can include pain and discharge from the anus. On the other hand, if eyes are affected, typical conjunctivitis symptoms will develop (redness of the eyes and inflammation). Only in case of throat infection, no symptoms will manifest whatsoever.

How is chlamydia transmitted and spread?

As a sexually transmitted disease, chlamydia is spread through unprotected sexual contact. This includes unsafe vaginal, anal or oral sex and in addition to that, it can also be transmitted through sharing of sex toys.

People affected by the condition will have bacteria present in the mucous membranes (soft red tissue inside vagina, penis, anus, eyes or mouth) as well as in genital fluids. The condition is spread through contact between the mucous membranes or, alternatively, contact between the genital fluids and the mucous membranes.

Is it possible to get chlamydia from oral sex?

Yes, practicing unprotected oral sex can result in chlamydia transmission. All the genital fluids and mucous membrane secretions can carry the bacteria. Unprotected oral sex means that chlamydia infection can travel from genitals to the mouth or alternatively, from anus to the mouth.

Despite this, the tissue in the mouth is significantly more resilient to bacterial infections, so despite the risks associated with this practice, oral sex is the least common mean of chlamydia transmission.

Is it possible to get chlamydia from anal sex?

Yes, unprotected anal sex carries significant risk of infection. The contact between sperm or penile fluids with the mucous membranes of the anus is a mean of chlamydia transmission and the same is also true – bacteria can be passed on from the mucous membranes of the anus to those of the penis.

Is sharing sex toys a mean of transmitting chlamydia?

Yes, sharing sex toys poses a risk of chlamydia infection. Sex toys should be thoroughly washed between users, or condoms should be used. Alternatively, the vaginal and anal secretions can be transmitted from one user to the other.

Can chlamydia be spread through kissing?

No, mouth-to-mouth kissing doesn’t pose you at risk of getting infected.

Are homosexual men at greater risk?

Homosexual men do account for somewhat higher percentage of chlamydia cases as compared to heterosexual men, but deeper understanding of this question is still significantly lacking. The greater susceptibility of gay men to certain STIs such as syphilis and gonorrhoea has been confirmed in the past. According to the statistical research conducted by Public Health England, men who have sex with men (MSM) accounted for 84% of all syphilis diagnoses and around 70% of gonorrhoea diagnoses at sexual health clinics.

The number of MSM affected by chlamydia was significantly higher than the number of those affected by syphilis, with the exact numbers being 12.805 to 4.192. However, this is still lower than 22.408 recorded gonorrhoea cases. In total, men who have sex with men accounted for 21% of male cases of chlamydia.

Are condoms an efficient protection against chlamydia?

Condoms are classified as barrier contraceptives, meaning that they prevent the couple using them from coming into contact with each other’s sperm or vaginal fluid. Thus, they are not only effective in preventing unwanted pregnancy, but are also very reliable as a protection against STIs, chlamydia included.

Despite the fact that condoms cannot offer 100% protection from STIs, they will dramatically reduce the chances of passing on chlamydia. If you and your partner haven’t tested for STIs recently, it might be best to use condom at all times.

However, if your chlamydia diagnosis is confirmed, it is recommended to abstain from sex (protected or unprotected) until you get proper treatment.

Can contraceptive pills protect me from getting chlamydia?

While contraceptive pills are considered to be among the safest contraceptives, effective in 99% of cases, they offer absolutely no protection from STIs, including chlamydia.

Can withdrawal method (coitus interruptus) prevent chlamydia spread?

No, withdrawal method isn’t a safe contraceptive practice and at the same time it doesn’t offer any protection from STIs whatsoever. The bacteria that cause chlamydia infection will be present both within sperm and vaginal fluid, but also in the mucous membranes secretions of those affected. What this means is that ejaculation is not necessary for the transmission to occur – small secretions of sperm as well as vaginal fluid can come into contact with mucous membranes, passing on the infection even prior to the climax.

Do I have chlamydia? How can I check?

If you have any reason whatsoever to suspect you might be infected by chlamydia, it is best to get tested, as that is the only way you can certainly confirm or deny the presence of Chlamydia bacterium within your body. In those cases where condition does cause certain symptoms, correct diagnosis from the symptoms alone can still be absent, as the majority of the symptoms of chlamydia are not specific or unique for that condition alone. In either case, there is just no alternative to proper STI test.

Can you notice if someone else has chlamydia?

Most of the time, this will not be possible. Not only is chlamydia completely asymptomatic in 50% of male cases and up to 80% of female cases, but some of its milder symptoms might completely miss your attention.

How can you test for chlamydia?

In order to get tested for chlamydia, you will have to provide a urine sample and, for women, vaginal swab. In certain cases, the medical professional might also request swab of the tip of the penis.

You can get tested either in the relevant institutions (GUM clinics, sexual health clinics, contraceptive clinics or general health medical institutions) or by ordering a self-sampling at-home STI test.

How can I test for chlamydia myself?

If you really wish to avoid talking to doctors about this uncomfortable topic, you can test yourself for chlamydia in the comfort of your home. Specialized at-home STI test kits will provide you with all the equipment you will need for gathering and storage of samples. Once you collected the required samples, you will post them to the relevant laboratory after which you will be notified about the results via your preferred method.

Is chlamydia curable?

Yes, chlamydia can be successfully treated with antibiotic medicines. If the condition has been confirmed through an STI test, the doctor will prescribe you one of the most commonly used antibiotic treatments for this issue – Azithromycin or Doxycycline. The former is a very potent one-off dose medicine, while the latter is usually prescribed as a one week course.

If there are some reasons why you can use neither Azithromycin nor Doxycycline, so-called second-line treatments might be prescribed instead. These include:

It is also important to note that Doxycycline should not be used during pregnancy, when some of the alternatives will be recommended.

How long does it take for chlamydia treatment to work?

In a majority of cases, chlamydia should clear up within a week or two after the beginning of antibiotic treatment. The symptoms, if present, will more or less begin to improve within the first week of the treatment. However, this is mostly true for those symptoms such as painful urination or genital discharge. On the other hand, women affected by chlamydia will notice that symptoms related to vaginal bleedings and menstrual cycle might need as much as four weeks to improve.

How long do I need to wait before having sex again after chlamydia treatment?

After you completed your treatment and all your symptoms disappeared, you should still wait another week prior to engaging in sexual activity.

Can you get chlamydia more than once?

Yes, it is possible to get infected with chlamydia a number of times. Successful treatment of one infection does not create any kind of immunity to subsequent infections and the same risk factors, most notably, unprotected sex, can easily lead to subsequent infections.


  1. STI Diagnoses & Rates in England by Gender – Public Health England