www.newscientist.com/channel/sex/mg18624954.500
Advertising DEATHS from cervical cancer could jump fourfold to a million a year by 20 50, mainly in developing countries. This could be prevented by soon-to-b e-approved vaccines against the virus that causes most cases of cervical cancer - but there are signs that opposition to the vaccines might lead to many preventable deaths. The trouble is that the human papilloma virus (HPV) is sexually transmitt ed. So to prevent infection, girls will have to be vaccinated before the y become sexually active, which could be a problem in many countries. In the US, for instance, religious groups are gearing up to oppose vaccin ation, despite a survey showing 80 per cent of parents favour vaccinatin g their daughters. "Abstinence is the best way to prevent HPV," says Bri dget Maher of the Family Research Council, a leading Christian lobby gro up that has made much of the fact that, because it can spread by skin co ntact, condoms are not as effective against HPV as they are against othe r viruses such as HIV. "Giving the HPV vaccine to young women could be potentially harmful, beca use they may see it as a licence to engage in premarital sex," Maher cla ims, though it is arguable how many young women have even heard of the v irus. Meanwhile in developing countries, where 80 per cent of deaths from cervi cal cancer occur, social taboos may be even more powerful. The head of t he Indian Council of Medical Research, N K Ganguly, says it will take a big educational effort to convince parents. Vaccinating men could be t he best way to prevent the spread of HPV among women. Half of all sexually active women between 18 and 22 in the US are infected. Most cases clear up, but sometimes infection persists and can cause cancer decades later. Deaths in the west have plummeted thanks to widespread screening to detec t cancers early. But such screening is not widely available in developin g countries. In many, populations are ageing: in India the number of wom en over 60 is projected to rise from 40 million now to 168 million in 20 50. The International Agency for Research on Cancer in Lyon, France, cal culates that by then deaths from cervical cancer will reach a million a year in poor countries if rates of infection, and of cancer detection an d treatment, do not improve. While vaccination could slash infection rates, its cancer-preventing bene fits will not be evident for decades, as it will take that long for vacc inated girls to reach an age when they might otherwise have developed ca ncer. Meanwhile, millions of women who are already infected must be scre ened and treated. If there is widespread resistance to vaccination, it w ill take even longer for its benefits to become clear. Vaccines are producing good results in clinical trials, and the first cou ld be licensed as early as next year. GlaxoSmithKline announced in Novem ber 2004 that its vaccine, which contains two strains of HPV thought to cause 70 per cent of cervical cancers, had prevented 90 per cent of new infections and all persistent infections. The US-based firm Merck announ ced similar results last week with its vaccine, which contains the same two cancer-causing HPV strains plus two strains that cause genital warts . Vaccinating men could be the best way to prevent the spread of the cance r-causing virus among women Merck's official reason for including the warts strains is that they can confuse screening tests, leading to unnecessary scares. But another reas on, says Anne Szarewski of the charity Cancer Research UK, who is helpin g to organise one of the vaccine trials, is that men who get vaccinated to prevent disfiguring warts will no longer transmit the cancer-causing strains to women. That might be the key to getting vaccines accepted in cultures where trying to prevent sexually transmitted infections is equa ted with promiscuity. "We found that some Asian women in Britain are afraid even to get tested for HPV infection, because they say if it is positive they will be kille d, never mind that their husbands probably gave it to them," says Szarew ski. She feels that such attitudes may mean that HPV vaccination may be a non-starter in such communities. Greg Zimet of Indiana University in Indianapolis is more optimistic. His surveys in the US show parents overwhelmingly favour getting their daugh ters vaccinated. India is planning to do its own clinical trials, but will not test the vaccine in young girls. "This is not possible until around the age of marriage in India," Ganguly says. Once licensed, the vaccine should be given to younger girls, he says. Ganguly is trying to arrange for an HPV v accine to be produced cheaply in India. But there are fears India's new patent laws will make licensing deals difficult.
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