9 April 2019

First estimates of the cost of chlamydia retesting in England for different recall methods published.

A study published by researchers at the University of Bristol, in partnership with Public Health England, has examined which method of recalling individuals for chlamydia retesting is the most economical. 

The study, published in BMJ Open, found that no active recall was the most economical way of delivering retesting, as the increase in retest rates with active recall did not outweigh the higher cost. Nurse-led contact by phone was particularly uneconomical, as was automatically sending out postal testing kits.

The National Chlamydia Screening Programme (NCSP) in England opportunistically screens eligible individuals for chlamydia infection. Following a positive test result, it is recommended that individuals are retested three months later, as they may be at risk of reinfection. Currently, a healthcare professional will have a conversation with the individual about retesting around the time of treatment for the first infection. However, no guidance is given on how local areas should recall individuals when retesting is due. 

The researchers of this study analysed the cost of the six most commonly-used methods of recalling individuals for retesting, such as contacting individuals by phone, sending text reminders, sending out a postal testing kit automatically, or doing nothing to chase up individuals for retesting (“no active recall”). The study included both clinic retesting, and retesting using postal kits, but did not consider on-line testing. Incomplete uptake, and non-return of postal kits, were incorporated in cost estimates. 

Lead author on the study, Dr Katharine Looker from the University of Bristol, said, “Our analysis suggests no active recall is the most economical way of recalling individuals for chlamydia retesting, although a text reminder could be considered. However, patient choice and accessibility of services should be taken into consideration.”  

The results of the study will enable local service planners to assess whether they are currently delivering retesting economically, or whether they should consider an alternative approach.

The study was funded by the UK’s National Institute for Health Research (NIHR) Health Protection Research Unit (HPRU) in Evaluation of Interventions at the University of Bristol, in partnership with Public Health England.

Chlamydia infection

Genital chlamydia infection is caused by the bacterium Chlamydia trachomatis. It is the most common bacterial sexually transmitted infection in the UK. The prevalence of infection is highest among sexually-active 15 to 24 years olds.

Chlamydia infection represents a substantial public health problem. Although infection is often asymptomatic, it can lead to a range of complications, including pelvic inflammatory disease (PID), ectopic pregnancy and tubal factor infertility (TFI) in women. In men, complications of chlamydia include epididymitis. It is easily passed from person to person through unprotected sex, especially as most people are unaware they are infected.

Dr Kevin Dunbar, from Public Health England, said, “People who are infected with chlamydia can be re-infected by their partners.  So it’s really important to notify your partner, make sure you get treated, and get retested after 3 months just in case you’ve become re-infected.”


Economic evaluation of the cost of different methods of retesting chlamydia positive individuals in England by Katharine Looker et al. Published in BMJ Open. 

Further information

The NHS gives this advice about preventing chlamydia infection:

Anyone who is sexually active can catch chlamydia. You’re most at risk if you have a new sexual partner or don’t use a barrier method of contraception, such as a condom, when having sex.

You can help to prevent the spread of chlamydia by:

  • using a condom every time you have vaginal or anal sex
  • using a condom to cover the penis during oral sex
  • using a dam (a piece of thin, soft plastic or latex) to cover the female genitals during oral sex or when rubbing female genitals together
  • not sharing sex toys

If you do share sex toys, wash them or cover them with a new condom between each person who uses them.