Postal screening for chlamydia is unsatisfactory

Evidence from a postal screening study has indicated that the best way of systematic chlamydial screening in the United Kingdom is still to be found. Postal screening, though feasible, gave limited coverage and risked missing those potentially at most risk.

The study within the ClaSS project invited nearly 20 000 people aged 16–39 randomly selected from general practitioner registers in west midlands and Avon to undergo postal screening for genital chlamydia. This entailed those contacted posting back to the practice samples they had taken themselves and a completed questionnaire on risk factors for infection.

Coverage achieved was 73%, and uptake was modest, just 22% to the initial invitation in the 16–24 age group, rising by about 5% with a postal reminder and a further 5% after a house visit or flagging medical records. Women responded better than men—25% versus 19% initially. Coverage was lower in communities with more ethnic minority groups and uptake was less in deprived areas.

Prevalence of infection was 5–6% in men and women aged under 25 but highest among those women who needed most reminders. Under 1% of men over 24 and women over 29 were positive. Having new sexual partners in the past year was a risk factor.

Systematic chlamydia screening could drastically reduce pelvic inflammatory disease. Opportunistic screening will start in England for women under 25, without good evidence of effectiveness. Randomised trials of postal screening in Denmark looked promising, but more are needed to find the right approach in England, it seems.