C-Card Scheme


Genital chlamydial infection (commonly referred to as chlamydia) is a sexually transmitted infection caused by the bacterium, Chlamydia trachomatis. It can be transmitted through unprotected vaginal, oral or anal sex or genital contact with an infected partner. It cannot be caught by casual contact (i.e. through toilet seats, swimming pools, saunas etc).

At least 50% of infected men and 70% of women do not have symptoms and so a large proportion of cases remain undiagnosed. However, people who have no symptoms are still able to pass the infection onto sexual partners. More information about chlamydia is available from NHS Direct Wales On-line

Who gets it and how serious is it?

Anyone who has sex can get genital chlamydial infection. The people at risk are those having unprotected sexual intercourse, especially with more than one sexual partner and those who change sexual partners.

Infection can also be passed to infants from an infected mother during birth causing conjunctivitis or pneumonia, both of which are treatable.

If left untreated, chlamydial infections can progress to serious reproductive and other health problems. In women, it can cause pelvic inflammatory disease (PID) which can lead to infertility and an increased risk of ectopic pregnancy. In men, complications are rarer but can very occasionally lead to infertility.


Uncomplicated chlamydia is easy to treat and cure with specific antibiotics. However, the consequences of PID are not easily treatable and can have lifelong implications for the individuals concerned.

How common is it?

Chlamydia is the most commonly reported bacterial sexually transmitted infection at Genitourinary Medicine (GUM) clinics in Wales and the UK. Highest rates are seen in young people, particularly men and women under 24.

In 2010, there were 4059 episodes of uncomplicated chlamydial infection reported by GUM clinics in Wales. However, a significant number of infections may go undiagnosed as many infected individuals do not have symptoms and therefore do not seek medical advice. 

More information about the surveillance of genital chlamydial infection in Wales is available from the Public Health Wales Health Protection Division microsite website from the link: rates and surveillance of chlamydia in Wales


Sexually active men and women can reduce their risk of chlamydia by reducing their numbers of partners, reducing frequency of partner change, and by using condoms correctly and consistently during sexual intercourse.

In addition, individuals can request confidential screening for chlamydia and other sexually transmitted infections, either from their GP or from a genitourinary medicine (GUM) clinic, lists of which are available from the FPA website. GUM clinics are completely confidential and will not inform GPs of results unless requested to do so by the patient. Clinics can be attended at any age.

Minimising impact in Wales

Public Health Wales has established the Sexual Health Programme which collects and collates data on the levels of sexually transmitted infections, including chlamydia, in the Welsh population. Such data allows significant trends and any particular groups of the population affected to be identified, and enables effective delivery of high quality, accessible and appropriate specialist public health services, both in partnership and support of other national and local bodies.