Chlamydia is the most common bacterial sexually transmitted infection, with sexually active young people at highest risk. As chlamydia often has no symptoms and can have serious health consequences (e.g. pelvic inflammatory disease, ectopic pregnancy and tubul factor infertility) opportunistic screening remains an essential element of good quality sexual health services for young adults.

A substantial proportion of all young adults become infected with chlamydia in a year. The aim of the National Chlamydia Screening Programme (NCSP) is to control chlamydia through early detection and treatment of asymptomatic infection, so reducing onward transmission and the consequences of untreated infection. From April 2003 to Sep 2013, the NCSP has delivered over 8,155,500 tests with 535,255 diagnoses made (15-24 year olds).

Looking at the impact of the NCSP in England, PHE modelling suggests that the substantial increases in the number of diagnoses made in England between 2000 and 2010/11 has probably decreased the prevalence of chlamydia among sexually active under 25 year olds. Several different approaches are currently being taken to try to estimate and monitor prevalence.

If you require more information on any of the content, or have suggestions for future content or resources, please email: NCSPteam@phe.gov.uk.