According to figures published today, the total number of STIs diagnosed in UK sexual health clinics is up by 6% on the previous year – from 375, 843 in 2006 to 397,990 in 2007.
Even though only one in eight of the population are aged 16 to 24, this age group accounts for around half of all newly diagnosed cases, the HPA said.
Those aged 16-24 accounted for 65% of all new cases of chlamydia, 55% of new cases of genital warts and half of all new cases of gonorrhoea.
The HPA said all sexually active youngsters should be screened annually for chlamydia, and every time they change their sexual partner.
Until they have been screened for STIs, everybody should use a condom with a new sexual partner and should avoid ‘overlapping’ sexual relationships, they added.
Professor Peter Boriello, director of the Agency’s Centre for Infections, said: ‘Substantial numbers of young people remain undiagnosed, untreated and unaware of the risk they pose both to their own health and that of their sexual partner.
‘It is crucial that young people continue to be exposed to messages about safe sex, including condom wearing, and the importance of getting checked out at their nearest GUM clinic if they have had unprotected sex with a new partner,’ he said.