DEATHS from cervical cancer could jump fourfold to a million a year by
2050, mainly in developing countries. This could be prevented by soon-to-be-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
transmitted. So to prevent infection, girls will have to be vaccinated before
they become sexually active, which could be a problem in many countries.
In the US, for instance, religious groups are gearing up to oppose
vaccination, despite a survey showing 80 per cent of parents favour vaccinating
their daughters. "Abstinence is the best way to prevent HPV," says
Bridget Maher of the Family Research Council, a leading Christian lobby group
that has made much of the fact that, because it can spread by skin contact, condoms
are not as effective against HPV as they are against other viruses such as HIV.
"Giving the HPV vaccine to young women could be potentially
harmful, because they may see it as a licence to engage in premarital
sex," Maher claims, though it is arguable how many young women have even
heard of the virus.
Meanwhile in developing countries, where 80 per cent of deaths from
cervical cancer occur, social taboos may be even more powerful. The head of the
Indian Council of Medical Research, N. K. Ganguly, says it will take a big
educational effort to convince parents. Vaccinating men could be the best way
to prevent the spread of HPV among women.
HPV is extremely common. 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
detect cancers early. But such screening is not widely available in developing
countries. In many, populations are ageing: in India the number of women over
60 is projected to rise from 40 million now to 168 million in 2050. The
International Agency for Research on Cancer in Lyon, France, calculates that by
then deaths from cervical cancer will reach a million a year in poor countries
if rates of infection, and of cancer detection and treatment, do not improve.
While vaccination could slash infection rates, its cancer-preventing
benefits will not be evident for decades, as it will take that long for
vaccinated girls to reach an age when they might otherwise have developed
cancer. Meanwhile, millions of women who are already infected must be screened
and treated. If there is widespread resistance to vaccination, it will take
even longer for its benefits to become clear.
Vaccines are producing good results in clinical trials, and the first
could be licensed as early as next year. GlaxoSmithKline announced in November
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 announced similar results
last week with its vaccine, which contains the same two cancer-causing HPV
strains plus two strains that cause genital warts.
Merck's official reason for including the warts strains is that they can
confuse screening tests, leading to unnecessary scares. But another reason,
says Anne Szarewski of the charity Cancer Research UK, who is helping 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 equated 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
killed, never mind that their husbands probably gave it to them," says
Szarewski. 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 daughters
vaccinated. "Doctors tend to fear the worst," he says.
But some problems have already surfaced. 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. "But
people will say 'My girl is very virtuous, why vaccinate?' It will be a real
challenge, not like other vaccines."
Last but not least is the cost. Ganguly is trying to arrange for an HPV
vaccine to be produced cheaply in India. But there are fears India's new patent
laws will make licensing deals difficult.
A
politician is a man who will double cross that bridge when he comes to it
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