By Jim Reed
It's thought the number of under 25s with Chlamydia has doubled
Not enough young people are getting tested for Chlamydia, which is now the most common sexually transmitted disease in the UK.
Local health bosses in England have missed their targets for screening 15 to 24-year-olds for the second year running.
In some areas less than 10% of young people were tested, a long way below the government's target of 17% or the 35% that health experts say is needed to stop the disease from spreading.
Chlamydia can leave women infertile and cause painful health problems in some men unless it is treated with a single dose of antibiotics.
A record 120,000 new cases of Chlamydia were diagnosed last year, most of those in young people.
It is now thought one in 10 under 25s carry the bug, a rate that has more than doubled in the last decade.
Sexual health workers call it the 'silent infection' because it can have no symptoms but left untreated can make women infertile.
In men it can lead to swelling or inflamed testicles. There is also growing evidence it can reduce sperm count, making it harder to have kids in the future.
Twenty-three-year old 'Charlotte' from Luton [not her real name], tested positive last year.
"I just wasn't feeling very well," she told Newsbeat. "The symptoms I had were cramps and a funny discharge. So I went to the doctors and they tested me for STDs and a couple of week's later it was explained I had Chlamydia.
"I was seeing somebody for three months and he was cheating on me with somebody else. When I found out the relationship ended there and then.
"I was devastated. The only thing I knew about Chlamydia was that it could affect your fertility. That for me could have been the end of my world because of how badly I want to have kids one day.
"I also had to tell my new partner. Luckily we hadn't had unprotected sex because I knew there was something wrong. He was great and just relieved it wasn't something more serious.
"I took some antibiotics for a week, had another test and it was negative. It was just a huge relief when those results came back because I thought it's out my system now."
The government wanted 17% of all young people tested for the bug last year but the overall figure was just 15.9% despite a huge publicity drive.
Newsbeat has found out that more than £3.5 million was spent on television adverts, postal screening kits and 'incentives' from shopping vouchers to hundreds of free iPods and Nintendo Wiis.
There are also big differences across the 152 local health trusts in England.
The best performing like Doncaster and Lambeth in London easily met the 17% screening target.
But most didn't. The figures show that Warwickshire was the worst performer, with just 4.2% of all 15 to 24-year-olds in the area screened.
Insiders reckon that throwing money at the problem isn't working and local health bosses need to find better ways of reaching young people.
The screening success of local authorities varies widely
In Doncaster, for example, a team employed by Terrance Higgins Trust, the sexual health charity, are sent in to bars and clubs to hand out testing kits.
Drinkers are told to go to the toilet with a small pot and return it straight away to the tester. The results arrive by text or a phone call a couple of days later.
In many other areas of the UK, young people's sexual health services are far less developed.
Only 60 of the 152 local health areas spoken to by Newsbeat could confirm they run a dedicated sexual health clinic aimed at young people even though most new cases of infection are in that age group.
Simon Blake from Brook, the sexual health charity, told Newsbeat the latest set of testing figures are disappointing.
"We're really worried about Chlamydia," he said. "If you only test 14% of young people, even if they are treated, the chances are there will be re-infection throughout the population. So we have to get 35% tested to get it under control."
At the moment it is up to each individual health authority to publicise its own Chlamydia testing service. In reality that means there are a huge number of different clinics, helplines and websites offering access to screening in different areas.
Brook wants to see one single website set up for the whole of England where people can order anonymous testing kits and then send samples back through the post to get their results.
"The young people we speak to at Brook want to go online to a national service, type in postcode and get a test sent to them.
"And at the moment we are hearing young people say it is too complicated. They don't want to go to a clinic or a GP. They want somewhere online and we just don't have that national system in place at the moment."
The government's new public health minister, Gillian Merron, said: "The National Chlamydia Screening Programme gives immediate benefit to everyone who takes part and means we are able to stop Chlamydia in its tracks.
"By detecting it earlier, we are making a real and measurable difference to the lives of young people.
"The rate of screening of young people is a major achievement. We are making significant progress and will continue to do so."