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THAT famous British reserve all but disappeared last week as warnings spread like wildfire that sexually transmitted diseases were on the increase, and that if they continued unchecked the country faced a public health disaster. National newspapers stoked the fires of moral indignation, and the British Medical Association even recommended that schoolchildren as young as five should be lectured about the dangers of unsafe sex.

The debate was sparked by two rather mundane studies, both published in the journal Sexually Transmitted Infections. One found that people nowadays are more accepting of casual and gay sex, and the other showed that people with STDs, especially men, are reluctant to tell their partners that they may have put them at risk. By the end of the week, the public was expected to believe that Britain is in the grip of an epidemic of STDs fuelled by lax sexual attitudes.

But are STDs really more of a threat now than ever? A glance backwards at the 20th century suggests that the grandparents and parents of today鈥檚 supposedly licentious youth lived in much more dangerous times. According to Britain鈥檚 Public Health Laboratory Service (PHLS), gonorrhoea was over three times as prevalent as today after the Second World War and about four times as common in the late 1960s and early 1970s. These days syphilis barely registers on the charts, whereas after the war, tens of thousands of cases were being reported each year (see Graphs). Even genital herpes infection rates have remained flat in recent years. And most public health officials admit that much of the apparent increase in chlamydia is simply due to better detection.

鈥淭here have been lots of successes,鈥� says Kevin Fenton of University College London and the PHLS. 鈥淚n general, we are winning the battle.鈥� Since 1995, there have been disturbing outbreaks of syphilis and gonorrhoea in isolated communities across Britain. But while the problem is serious, Fenton says it has to be viewed in context. 鈥淚t鈥檚 all relative,鈥� he says. 鈥淲e鈥檝e seen such dramatic declines.鈥�

The situation is similar in the US, where syphilis is at an all-time low鈥攕o low that the US Centers for Disease Control and Prevention in Atlanta has concluded that it could be eradicated. Though there was a small increase in rates of gonorrhoea in the late 1990s, infections went down by 10 per cent a year in the decade preceding that rise. There is no evidence that there are fewer cases of genital warts, but chlamydia is thought to be declining.

Everyone agrees that there鈥檚 no excuse for complacency. Even the STDs that don鈥檛 kill can cause considerable suffering. Untreated, chlamydia can cause pelvic inflammatory disease, which can lead to infertility, for instance. And some types of human papillomavirus, which produce genital warts, lead to cervical, penile and anal cancers.

The British Medical Association has called for more sex education and public health campaigns. But education can only do so much. The most effective way to reduce rates of STDs may lie in better screening, including faster, easier and cheaper tests, and more options for protection than condoms alone.

Many STDs, such as syphilis, gonorrhoea and chlamydia, are bacterial, and are easily treated with antibiotics. Yet often they go undiagnosed, increasing the chances of being passed on. 鈥淭here鈥檚 a huge misconception out there that people who have STDs will know it,鈥� says Edward Hook at the University of Alabama in Birmingham. But many don鈥檛: often they have no symptoms, or ignore them. 鈥淲e鈥檙e all masters of denial,鈥� he says.

The only way to address that problem is through screening, says Hook. In the US, federal guidelines encourage the screening of high-risk populations鈥攆or instance, testing all sexually active women under 24 for chlamydia. But the guidelines are not always acted on. Similarly, people in Britain are only screened once they attend a genitourinary medicine clinic. However, Fenton believes that screening the general population will be introduced in Britain within the next decade.

Advances in testing methods have already made widespread screening much more practical. There are now four or five rapid tests for STDs that amplify signature amino acids in a urine sample. 鈥淭hey are all more sensitive than the old gold standards,鈥� says Hook. And although the cost is still prohibitive for some, the tests avoid the embarrassment and discomfort of a swab. All you need to do is pee into a cup.

Sexual behaviour is still a very strong determinant of STD rates, says Fenton. Having many partners, not using condoms and having gay sex all increase a person鈥檚 chance of contracting an STD. But Fenton admits there aren鈥檛 a lot of options for people who want to practise safe sex.

鈥淲e鈥檝e been singing the same condom mantra for fifty years,鈥� says Sharon Hillier at the University of Pittsburgh School of Medicine. 鈥淭he problem with condoms is not their effectiveness but that they鈥檙e not used.鈥� She researches 鈥渕icrobicides鈥濃�攖opical products that aim to prevent the transmission of HIV and other STD pathogens (see The future of safe sex). There are no microbicides on the market yet, but three are about to begin clinical trials.

Though less effective than condoms, microbicides may end up protecting more people from STDs, simply because people may be more willing to use them, says Megan Gottemoeller of the Program for Appropriate Technology in Health, based in Washington DC. But there鈥檚 little scientific or commercial interest in these products as they don鈥檛 rely on cutting-edge science and won鈥檛 make big money early on. And policymakers 鈥渨ant to fix this epidemic without mentioning 鈥榮ex鈥� or 鈥榲agina'鈥�, she says.

Another promising front is vaccination. Vaccines against human papilloma virus and HIV are in phase II and phase III trials respectively in the US. Other vaccines against chlamydia are in earlier stages of development. So far, only the herpes vaccine has proved effective鈥攑roviding about 75 per cent protection鈥攂ut it doesn鈥檛 work in men.

Ideally, all prepubescent girls would receive the anti-herpes jab. But it might be difficult to persuade parents to get their daughters vaccinated, and could stir up an intense moral and scientific debate in its own right. 鈥淭here鈥檚 some concern that if you give kids an STD vaccine, it will give them permission to go out and have sex,鈥� says Susan Rosenthal, a psychologist at the University of Texas Medical Branch in Galveston. She feels that鈥檚 unlikely, but says the vaccine will only work if it is routinely given to all girls.