At least 70 per cent of women and 50 per cent of men infected with Chlamydia trachomatis are asymptomatic.18 
While chlamydia diagnosis rates are generally stable among men across all age groups and most women’s age groups, diagnoses have followed an upward trend since 2015 among women aged in the 20-24 years group. 
Chlamydia testing among young people (15-24 years) increased 2 per cent year-on-year in 2019 to 1.34 million tests but is down 13 per cent compared to 2015. Use of internet testing increased 22 per cent in 2019, accounting for 20 per cent of chlamydia tests and 17 per cent of chlamydia diagnoses. 
The National Chlamydia Screening Programme recommends annual screening for all sexually active people younger than 25 years of age, or more frequently if they change their partner.17 
The NICE CKS on treating uncomplicated chlamydia in primary care recommends doxycycline 100 mg twice daily for 7 days as the first line treatment. Alternatives are:17 

• azithromycin 1g orally for one day, then 500mg once daily for two days; or
• erythromycin 500 mg twice daily for 10–14 days; or
• ofloxacin 400mg daily (as a single dose or in divided doses) for seven days. 

For pregnant women, the recommended treatment options are:  

• azithromycin 1g orally for one day, then 500mg once daily for two days, or
• erythromycin 500mg four times daily for seven days; or
• erythromycin 500 mg twice daily for 14 days; or
• amoxicillin 500 mg three times a day for seven days.