Abstract
Sexually transmitted infections (STIs) are a major public health problem worldwide, affecting quality of life, adding economic burden and causing serious morbidity. Chlamydia infection is the most common bacterial STI, making up a large proportion of the over 1 000 000 STIs acquired every day. Although easily cured with antibiotics, untreated chlamydial infection can have serious consequences affecting reproductive health and the unborn child. Since chlamydia infection is typically asymptomatic, screening provides an opportunity to prevent complications and reduce transmission. With long waits for genitourinary medicine appointments and busy sexual health clinics, screening in primary care can help to improve chlamydia detection and treatment rates.
The GP curriculum and chlamydia screening
Be able to perform an appropriate risk assessment through history-taking via a holistic and integrated approach Be able to manage sexual health problems, and in particular, be able to assess the risk of having undiagnosed HIV (a consequence of STIs) Have sensitive, non-judgemental communication skills Co-ordinate care and make timely, appropriate referrals to specialist services knowing the boundaries of what is reasonable and practicable in general practice Promote health through a health promotion or disease prevention programme Engage in the implementation of locally agreed health programmes Understand the concept of risk and be able to communicate risk effectively to patients and their contacts Has responsibility for individual patients, their family and the wider community Will be involved in the management of healthcare delivery in their practice and improving the health and well-being of the community
What is chlamydia?
Chlamydia trachomatis is a ubiquitous gram-negative intracellular bacterium. It has a life cycle of 48 to 72 hours, but is susceptible to various antimicrobial agents. The main sites of infection are the mucous membranes of the urethra, endocervix, rectum, pharynx, and conjunctiva. Transmission is by direct inoculation of infected secretions from one mucous membrane to another. Sequelae in women include: pelvic inflammatory disease (PID); ectopic pregnancy; tubal infertility; premature rupture of membranes; preterm delivery; and postpartum endometritis. Proctitis, epididymitis and epididymo-orchitis occur in men. Vertical transmission of chlamydia during childbirth can also cause neonatal pneumonia and conjunctivitis, which if not treated, can lead to blindness.
Epidemiology
Worldwide, 131 000 000 chlamydial infections are detected annually, making it the most common bacterial sexually transmitted infection (STI). It is also considered to be the leading cause of PID and female infertility (World Health Organization (WHO), 2016a). In 2016, there were 202 546 new diagnoses of chlamydia made in England, representing 49% of new STI diagnoses. A decrease of 4% was noted from the previous year, which may have been due to a reduction in the numbers presenting for screening (Public Health England (PHE), 2016).
An estimated two thirds of sexual partners of individuals with chlamydia will also have chlamydia infection. This emphasises the need for contact tracing and synchronised treatment of partners to prevent re-infection. Untreated infection may persist for more than a year in 50% people, but about 95% will clear spontaneously after 4 years. The cost of chlamydia complications is estimated at over £100 000 000 annually in UK.
Risk factors for chlamydia
Age is the most useful demographic or behavioural risk factor for chlamydia infection, and in fact, almost all STIs. Figure 1 illustrates the rates of new STI diagnoses among people attending sexual health services by age-group and gender.
Rates of new STI diagnoses among people attending sexual health services by age-group and gender.
Young men and women aged between 15 and 24 years are consistently at higher risk of being infected with chlamydia than older subjects. In women, this may in part be due to the anatomical differences in the cervix at a younger age, wherein the squamo-columnar junction, a primary host target for the bacterium, is everted and thus more exposed. Other associated risk factors include a ‘chlamydia-positive’ sexual partner, two or more sexual partners in the preceding year, not using barrier contraception, infection with another STI, genetic predisposition and low socio-economic status.
Manifestation of chlamydia
Most cases of chlamydia are asymptomatic and are only detected during screening or investigation of other genitourinary illness. Around 50% of men and 70% of women do not exhibit any symptoms of the infection (National Institute for Health and Care Excellence (NICE), 2016), hence the emphasis upon prevention and screening. Symptomatic women may complain of vaginal discharge, dysuria, abdominal pain, dyspareunia or intermenstrual or post-coital bleeding. In men, there may be dysuria, urethral discharge, or testicular pain and/or swelling. Fever may also be a presenting feature in men. In both sexes, it is important to note symptoms indicative of reactive arthritis, perihepatitis, proctitis and pharyngeal infections as these may suggest an underlying chlamydia infection.
Diagnosis
Chlamydia is diagnosed by analysing swabs or urine using nucleic acid amplification techniques (NAATs). NAATs are a very sensitive way of detecting DNA and have replaced enzyme immunoassays. Endocervical or vulvovaginal swabs can be taken in women, with first-catch urine (not mid-stream urine) or urethral swabs suggested for men (NICE, 2016). NAAT sensitivity with vaginal swabs (93%) is as high as or higher than NAAT sensitivity with cervical swabs (91%). First-catch urine NAAT testing can also be used in women, but is less sensitive than vaginal or endocervical swabs (Schachter et al., 2003).
Who should be tested for chlamydia?
SIGN guidelines on groups to be tested for chlamydia.
Screening for chlamydia
Aim and purpose
Mathematical modelling suggests that screening could reduce the prevalence, and thus morbidity, and complications of chlamydia infection. The National Chlamydia Screening Programme (NCSP), established in 2001 in England, aims to test all sexually active men and women under the age of 25 years by providing easy access to testing and treatment in a wide range of healthcare and non-healthcare settings. The NCSP aims to make free chlamydia testing for under-25-year olds available at GP surgeries, community pharmacies, sexual health clinics, and via the internet (PHE, 2016).
Having chlamydia screening widely available without charge allows young people to take responsibility for their sexual health, regardless of their location or proximity to specialist clinics. Additionally, the offer of a chlamydia test in a wide range of settings is well received by young people and helps to normalise STI testing. For many young people the offer of a chlamydia test will be their first contact with sexual health services, and as such provides an important opportunity to support young people by improving knowledge and attitudes.
Chlamydia testing coverage, detection rate and percentage testing positive differ from area to area. In 2016, the percentage of young people tested for chlamydia ranged from 16 to 27% (highest rates in London). There was an overall 9% decline in the number of tests and a 2% decline in the number of diagnoses from all service settings in 2016 compared with 2015 (PHE, 2017). One explanation for this decline could be that in recent years we have seen a rise in sexual health services offered online, meaning that internet-savvy young people use that approach do not seek help elsewhere.
PHE recommends that local areas work towards achieving a detection rate of at least 2300 per 100 000. Local authorities have a statutory duty to ensure the provision of open-access services, including free STI testing and treatment. Chlamydia screening should be offered as an integrated component of existing sexual and reproductive health services including primary-care-based services. Local authorities should also consider commissioning internet-based testing and pharmacy-based testing to ensure that young people have universal access to testing, as these services have high positivity and are readily accessed by young people (PHE, 2016).
Eligibility criteria
The NCSP is aimed at:
Men and women under 25 years in age who have been sexually active and who are offered, or request, a chlamydia test 15 and 16 year olds who meet the Fraser criteria for consent to testing Contacts of test positives, regardless of age People of all sexual orientations
The exclusion criteria includes patients who cannot give consent, those unwilling to give any means of contact for the purpose of result notification, and under-16-year-olds deemed not to meet the Fraser criteria.
Challenges and obstacles
The NCSP has faced challenges, including the Prevention of Pelvic Infection trial, which showed that most cases of PID occurred in women who had tested negative for chlamydia at baseline, implicating incident infection and casting doubt over the effectiveness of a single annual test for chlamydia to prevent PID (Oakenshott et al., 2010). However, most health economic impact evaluations show chlamydia screening to be cost-effective (RCGP and British Association for Sexual Health and HIV (BASHH), 2013) and a review of randomised trials concluded that the screening programme was cost-effective in terms of preventing PID (Gottlieb et al., 2013).
The environment in which screening takes place is also important. Young people do not like to publically seek help on sexual matters. Screening via primary care is usually seen as acceptable. Screening can be offered by any member of the practice team, including receptionists, and should be accompanied by appropriate written information. Information leaflets are available from the NCSP (NCSP 2017).
Surveys reveal that young people prefer:
The use of the word ‘test' rather than ‘screen' Testing to be normalised, thus phrases like ‘It's something we offer to all young people’ are positively taken Routine ‘offering' of testing rather than putting the impetus on them to ask Emphasis that the test is free, painless, self-administered and, if positive, the problem is easy to treat
The greatest barriers to opportunistic chlamydia testing in a primary care setting are lack of knowledge by staff of the benefits of testing, when and how to take specimens, lack of time, worries about discussing sexual health and lack of guidance. These barriers can be overcome in general practice through effective clinical leadership and staff training, but due to the resource implications many surgeries signpost patients to a genitourinary medicine (GUM) clinic, online services or other practices that offer an enhanced service in sexual health.
Management
Where chlamydia is diagnosed by screening in primary care the GP has three options: refer the patient to a GUM clinic; offer antibiotic treatment and refer to GUM for partner notification and follow-up; or arrange all treatment, notification and follow up within primary care (RCGP and BASHH 2013). Referring to a GUM clinic is often most appropriate, as detailed explanation of sequelae of untreated chlamydia, checking adherence to medication, contact tracing and further treatment for other diagnosed STIs can be a lengthy process requiring a specialist setting and expertise. However, in situations where a patient is reluctant to attend a GUM clinic or a delay in starting treatment is considered likely, the GP should offer antibiotic treatment, offer further full STI screening and arrange partner notification. They should also promote safer sexual behaviour and encourage early healthcare-seeking behaviour as part of preventative counselling.
Partner notification
When chlamydia is diagnosed through asymptomatic screening, all sexual partners in the previous 6 months should be notified. Patients may inform partners themselves (patient referral) or supply details for a healthcare worker to notify the partner without disclosing their identity (provider referral). Examples of notification slips can be found in RCGP and BASHH guidance (RCGP and BASHH, 2013). These approaches may be combined, whereby a time frame is agreed for patients to inform partners before the healthcare worker notifies those who have not sought care (contract referral). Patient referral is the method used most frequently, partly because most patients prefer to notify their own partners and also because provider referral is not available in some settings. The stigma attached to STIs can, however, make informing partners a traumatic experience. Provider referral is therefore an important service to protect patients from adverse consequences and reach partners who would not otherwise be informed, thereby improving disease control.
Medication
Medication for chlamydia.
Source: WHO (2016b).
Adherence with oral therapy for STIs over several days is often suboptimal and gets worse the more frequent the daily dosage. As with other medications, adherence may be poor for many reasons, ranging from patients being asymptomatic, the symptoms of infection clearing quickly, the presence of side effects, and lifestyle issues.
A test of cure is not routine unless the patient is pregnant, has persistent symptoms, non-compliance is suspected or if they have been re-exposed. It should be done at least 3 weeks after treatment when indicated. The NCSP recommends that young people under the age of 25 years and who have tested positive for chlamydia should have a repeat test 3 months later. A telephone call a week after treatment can be useful to check compliance and partner notification and reinforce health education (RCGP and BASHH, 2013).
KEY POINTS
Chlamydia is an easily treatable STI Untreated chlamydia can have serious consequences including PID and infertility Screening for asymptomatic infection aims to reduce complications and transmission The NCSP, although criticised, is thought to be cost-effective in detecting chlamydia infection and reducing rates of PID