Background In England, the National Chlamydia Screening Programme aims to control chlamydia infection in young adults (aged 15–24 years old) through opportunistic testing. This study aimed to investigate the impact of testing on young adults’ subsequent healthcare seeking and sexual behaviour. Young adults’ attitudes to chlamydia and chlamydia testing are important barriers to screening, and thus questions on attitudes to testing and reasons for not testing were included.

Methods A cross-sectional web-based anonymous survey of 1,521 young adults aged 16–24 resident in England was conducted using a nationally representative research panel. The impact of chlamydia testing on subsequent behaviour, and attitudes towards chlamydia testing, were assessed by asking respondents to use a Likert scale to score how well they agreed with a series of statements.

Results Just under half (46%; 695/1,521) of respondents had been tested for chlamydia previously: of whom 14% (94/695) reported ever having received a positive result. Those tested (n = 695) reported a positive impact on subsequent healthcare seeking behaviour (e.g. 68% agreeing that they were more likely to test again), and a smaller impact on sexual behaviour (e.g. 40% agreeing that they were more likely to use condoms consistently). Having positive attitudes towards chlamydia testing was associated with a higher likelihood of having been tested (OR 4.9; 95% CI 3.9–6.1). Of those sexually active but not tested (32%; 488/1,521), 70% did not consider themselves to be at risk.

Conclusions Young adults reported that being tested for chlamydia had a positive impact on their willingness to engage with future testing, and a smaller impact on subsequent sexual behaviour. The use of online surveys is warranted as the results were comparable to those of nationally representative population based surveys. Addressing young adults’ underlying attitudes towards testing and perceptions of risk could increase their willingness to test for chlamydia.