Incidence and reinfection rates of genital chlamydial infection among women aged 16-24 years attending general practice, family planning and genitourinary medicine clinics in England: a prospective cohort study by the Chlamydia Recall Study Advisory Group.

BACKGROUND: In England, screening for genital chlamydial infection has begun; however, screening frequency for women is not yet determined. AIM: To measure chlamydia incidence and reinfection rates among young women to suggest screening intervals. METHODS: An 18-month prospective cohort study of women aged 16-24 years recruited from general practices, family planning clinics and genitourinary medicine (GUM) clinics: baseline-negative women followed for incidence and baseline-positive women for reinfection; urine tested every 6 months via nucleic acid amplification; and behavioural data collected. Extra test and questionnaire completed 3 months after initial positive test. Factors associated with infection and reinfection investigated using Cox regression stratified by healthcare setting of recruitment. RESULTS: Chlamydia incidence was mean (95% CI) 4.9 (2.7 to 8.8) per 100 person-years (py) among women recruited from general practices, 6.4 (4.2 to 9.8) from family planning clinics and 10.6 (7.4 to 15.2) from GUM clinics. Incidence was associated with young age, history of chlamydial infection and acquisition of new sexual partners. If recently acquiring new partners, condom use at last sexual intercourse was independently associated with lower incidence. Chlamydia reinfection was mean (95% CI) 29.9 (19.7 to 45.4) per 100/person-year from general practices, 22.3 (15.6 to 31.8) from family planning clinics and 21.1 (14.3 to 30.9) from GUM clinics. Factors independently associated with higher reinfection rates were acquisition of new partners and failure to treat all partners. CONCLUSIONS: Sexual behaviours determined incidence and reinfection, regardless of healthcare setting. Our results suggest annual screening of women aged 16-24 years who are chlamydia negative, or sooner if partner change occurs. Rescreening chlamydia-positive women within 6 months of baseline infection may be sensible, especially if partner change occurs or all partners are not treated.

Relationship of cervical ectopy to chlamydia infection in young women.

OBJECTIVE: Genital Chlamydia trachomatis infection is the most common bacterial sexually transmitted infection (STI) in the UK. Behaviours including multiple sex partners and inconsistent condom use, and biological factors such as cervical ectopy, may increase susceptibility to STIs. Cervical ectopy is thought to increase risk of chlamydia infection by exposing columnar epithelium to a potential infectious inoculum. This study aimed to determine whether chlamydia was more prevalent in young women with cervical ectopy. METHODS: Clinical notes of women aged 16-24 years attending the Portsmouth Genitourinary Medicine Clinic for an STI screen during the period May-July 2003 were reviewed retrospectively. Information collected included the presence or absence of cervical ectopy, smoking habits, methods of contraception, number of sexual partners in the previous 3 months, and previous STIs. Chlamydia infection was diagnosed by using strand displacement amplification on cervical swabs. RESULTS: A total of 231 women were included in the study. The mean age was 19.8 years. Evidence of cervical ectopy was found in 107 women. Chlamydial infection was detected in 37.4% (40/107) of those women with cervical ectopy and 21.8% (27/124) in those without cervical ectopy. This difference was statistically significant (p = 0.009). The significance remained even when accounting for confounding variables. CONCLUSIONS: Cervical ectopy is a common physiological process in young women. Recognition of cervical ectopy should alert the clinician to the possibility of a genital chlamydia infection. Opportunistic screening for chlamydia in young people should be offered to reduce the prevalence of infection and its sequelae.

Chlamydia screening in primary care: is it useful, affordable and universal?

Genital chlamydial infection, with its possible long-term morbidity, is a serious public health problem. The number of new diagnoses is rising rapidly and, in the UK, recent evidence suggests that the infection rate in young women exceeds 10%. Screening programmes can reduce the population prevalence of infection, but uncertainty remains as to the ideal screening model. This may prove to be opportunistic screening of sexually active young women, less than 25 years of age, in primary care settings, and contact tracing of the partners of those with chlamydia. Recent literature on the practicalities of genital chlamydia screening is reviewed.