EPIDEMIOLOGY OF GENITAL CHLAMYDIA-TRACHOMATIS IN ENGLAND AND WALES

Objective: To describe the recent epidemiology of genital Chlamydia tr achomatis infection in England and Wales. Design: Retrospective study of routinely available surveillance datasets and ad hoc prevalence stu dies. Methods: Numbers of new cases of genital C trachomatis infection , obtained from the Department of Health and Welsh Office, were combin ed with the estimated mid-year resident population of England and Wale s. Rates were analysed for trend over time using a log linear age peri od model in GLIM4. Ad hoc prevalence and case finding studies carried out over the past 20 years were critically assessed in terms of study design and testing methodologies. Results: Attendance rates at genitou rinary medicine (GUM) clinics were higher for women than men over the period 1989 to 1994 as were the number of laboratory reports. The high est rate of attendance (GUM clinic data) was for women aged 16 to 19 y ears. There was an overall significant linear decrease in the attendan ce rates over time for both men (p = 0.0172) and women (p = 0.0000) be tween 1989 and 1994. There was considerable variation in the prevalenc e of genital C trachomatis infection detected within different clinica l settings, together with a substantial level of asymptomatic infectio n. Conclusions: Genital C trachomatis infection is broadly distributed throughout the sexually active population, with a substantial reservo ir of asymptomatic infection among those generally perceived to be at low risk of a sexually transmitted infection. Young people, particular ly women aged 16 to 19 years, are at highest risk of genital C trachom atis infection. This is of concern since younger women are more suscep tible than older women to developing complications of chlamydial infec tion, such as pelvic inflammatory disease. The broad distribution of i nfection across all sexually active health service attenders and the h igh level of asymptomatic infection suggest that a new, screening base d, approach to the control of genital C trachomatis infection is requi red. Recommendations are made as to the epidemiological research requi red to guide such work.