People who got carried away over the festive period are being reminded of the need to take care of their sexual health.
According to the STI Clinic website, sexually transmitted infections (STIs) can take up to 14 days to be detectable.
This means that anyone who had unprotected sex over the festive period should seriously consider getting tested so that they can be treated if necessary and avoid infecting future sexual partners.
Common STIs include Chlamydia - which often presents no obvious symptoms - genital herpes and gonorrhoea.
According to the Terrence Higgins Trust, nearly half of all STI diagnoses in the UK in 2007 affected the 16 to 24 age group.
The trust, which is the UK's leading HIV and sexual health charity, also estimates that around one in ten under-25s in the UK have Chlamydia but are unaware that they are infected.