Guidance

NCSP: programme overview

Updated 24 June 2021

Chlamydia

Chlamydia is the most commonly diagnosed sexually transmitted infection (STI) in England. The prevalence of infection is highest in young sexually active women (15 to 24 year olds).

Chlamydia often has no symptoms but, if left untreated, can have serious health complications in women including pelvic inflammatory disease (PID), ectopic pregnancy and tubal factor infertility (TFI). Complications in men are much rarer and an infection will often resolve without treatment in those who are asymptomatic.

NCSP objectives

The primary aim of the National Chlamydia Screening Programme (NCSP) is to reduce the health harm caused by untreated chlamydia infection.

The programme has the secondary aims of:

• reducing re-infections and onward transmission of chlamydia
• raising awareness of good sexual health

Opportunistic screening (that is the proactive offer of a chlamydia test to young people without symptoms) should focus on women*, combined with reducing time to test results and treatment, strengthening partner notification and re-testing after treatment

In practice this mean that chlamydia screening in community settings, such as GPs and pharmacies, will only be proactively offered to young women. Services provided by sexual health services remain unchanged.

Everyone can still get tested if they need, but men will not be proactively offered a test unless an indication has been identified, such as being a partner of someone with chlamydia or having symptoms.

*References to women throughout this document includes cisgender women, transgender men and non-binary (assigned female at birth) people who have not had hysterectomy or bilateral oophorectomy.

Chlamydia screening policy

The best way to protect against any STI is to consistently use a condom. Health promotion should continue to be offered to people requesting or being offered a chlamydia test.

The NCSP recommends that anyone whose partner is known to be infected, or who has symptoms of chlamydia infection, has a chlamydia test. Symptoms include pain when peeing, unusual discharge from the vagina, penis or anus; symptoms in women include pain in the tummy, bleeding after sex and bleeding between periods; symptoms in men include pain and swelling in the testicles.

To detect and treat chlamydia infection in women as early as possible, the NCSP also recommends that all sexually active women under the age of 25 get tested:

• after having sex with a new partner
• annually

To ensure that this happens, it is recommended that all sexually active women under the age of 25 accessing a sexual and reproductive health service (including online), any service offering contraception, termination of pregnancy service, GP or pharmacy should be offered a chlamydia test. Local areas should also consider offering appropriate outreach programmes in line with local need.

Everyone who is diagnosed with chlamydia should be treated as early as possible and supported to notify their sexual partner(s) and should be re-tested around 3 months after treatment.

Anyone of any gender who is concerned they might be at risk of chlamydia should contact their local sexual health clinic or GP for professional health advice about whether to get tested. Some groups of people are at higher risk of STIs (including chlamydia). More information about STI risks, how to protect against STI and where to access STI testing can be found on NHS.UK.

Rationale

Chlamydia:

• is the most common bacterial sexually transmitted infection; prevalence of chlamydia in 16 to 24 year old population is approximately twice the prevalence in 16 to 44 year olds (3.1% compared to 1.5% in women)
• is often asymptomatic; around 70% to 80% of people with chlamydia will be unaware that they have the infection
• has serious consequences if left untreated, including pelvic inflammatory disease (PID), tubal factor infertility and ectopic pregnancy in women — of those women with untreated chlamydia 10 to 17% will develop PID and 35% of PID in women aged 16 to 24 is attributable to chlamydia
• can be detected and treated easily and screening can reduce the risk of complications for an individual — women who have a chlamydia screen have a 36% lower risk of developing pelvic inflammatory disease compared to those who have not

The reasons for aiming to reduce harm from untreated chlamydia infection by focusing opportunistic screening on women and optimising management of those diagnosed with chlamydia are that:

• most of the harm caused by untreated chlamydia is in women — there is consistent evidence that untreated chlamydia infection in women increases their risk of ill-health and infertility
• there is no consistent evidence that screening of both men and women at the levels that can be feasibly achieved has measurably reduced the prevalence of chlamydia infection in the population
• shortening the duration of infection through early detection and treatment decreases the risk of pelvic inflammatory disease which can lead to infertility and ectopic pregnancy
• testing frequently and soon after any new sexual partner will reduce the duration women are infected, which should reduce the risk of harmful consequences for women
• men who have chlamydia are at much lower risk of harm, and infection will often resolve without treatment in those without symptoms — any man who is concerned they might be at risk of chlamydia can still access health advice at local services, online or by telephone
• many people get re-infected after treatment and there is evidence that repeat infections increase the risk of harm — it is therefore important that sexual partners of a person diagnosed with chlamydia are informed of the need to get tested and treated and that any person diagnosed with chlamydia gets re-tested between 3 and 6 months after their treatment

Background and history of the NCSP

In 1996, the Chief Medical Officer’s Expert Advisory Group on Chlamydia trachomatis was established to review the evidence base associated with screening programmes for chlamydia. The group reported in 1998 and proposed that chlamydia screening be introduced in England on an opportunistic screening basis.

The NCSP was implemented on a phased roll-out basis in 2003, with national implementation by 2008.

In 2017, PHE commenced the English NCSP Evidence Review. This involved assembling a detailed review of current evidence; inviting an external group of experts to review the evidence and provide a report of how best to improve chlamydia control activities in England; stakeholder and public consultation.