IN GLOBAL health terms, it is hard to find a more striking yardstick with which to measure inequality. Of the 275,000 women who die from cervical cancer every year, more than 85% are in the world’s poorest countries — yet the vaccine that could prevent 70% of these deaths has not been available partially because of its high cost.

Indeed, human papillomavirus (HPV) vaccines, which can cost as much as $130 for each of the three doses needed to provide protection against this deadly form of cancer, have been part of routine immunisation in some wealthy countries since 2007. Meanwhile, women in the countries with the highest burden of disease, where they typically have no access to screening or treatment, have no access to the vaccine even if they could afford it.

But that is about to change. This gross inequity will be addressed through a vaccination programme that will mark a transformational moment in women’s health. Thanks to its innovative market-shaping strategy and close partnership with pharmaceutical companies, the Global Access to Vaccines Initiative (Gavi) Alliance announced this week at the World Economic Forum on Africa in Cape Town that it is now able to purchase HPV vaccines at an initial price of just $4.50 a dose, with further reductions based upon the volume of demand.

This means that, starting with demonstration programmes in eight developing countries in the coming months, it will be possible for more than 30-million of the world’s poorest girls to be vaccinated by 2020.

However, not everyone believes this is a good idea. HPV is a highly transmissible and common virus and the cause of virtually all forms of cervical cancer. But it is also sexually transmitted, which means there are stigmas associated with it and the vaccine that can protect against it. Some critics say that since the vaccines are not given to infants, instead being provided to girls before they are sexually active — between the ages of nine and 13 — it effectively gives tacit consent to engage in sexual activity, ultimately leading to promiscuity. Others say there is little long-term data and inadequate surveillance to show mass HPV vaccinations work.

Consider the evidence, though. Certainly it is true that the two HPV vaccines so far approved by the World Health Organisation (WHO) target only two of the 15 types of virus known to cause cervical cancer.

But it is also true that these two types of the virus, HPV 16 and HPV 18, are by far the most prevalent cancer-causing strains. In fact, there is even research to suggest that with HPV vaccines there can be some cross-protection, providing immunity against HPV types not targeted by the vaccine.

Convincing evidence is now also emerging of the long-term benefits.

Last year the medical journal The Lancet published a study involving more than 18,000 women and girls in Australia, which showed a decrease in incidence of precancerous cells in women just three years after the introduction of a mass vaccination programme, covering all women aged between 12 and 26 years.

Similarly, numerous studies have found fear over increases in promiscuity to be unfounded. One recent study involving nearly 1,400 girls was published at the end of last year in the journal Pediatrics.

It found that after three years there was no difference between the degree to which vaccinated and unvaccinated girls sought pregnancy tests, chlamydia tests or birth-control counselling — markers that in rich countries are considered surrogates of sexual activity.

The fact is HPV vaccinations work, which is why since 2009 the WHO has recommended that these be included as part of national immunisation programmes. Moreover, this view is clearly shared by the governments of countries that bear the disproportionate burden of cervical cancer deaths. Since the Gavi Alliance began accepting applications for HPV vaccine support last year, it has received unprecedented demand, with 15 countries applying last year and as many as 20 expected this year.

Most important, however, it is recognised by women in these countries, where screening is not an option and where the HPV vaccine is their only hope. They have seen too many of their peers die a painful death from cervical cancer in the prime of their lives. For them, this programme is truly about changing lives, offering millions of women and girls a chance of a healthy future. And where women are empowered, families, communities and nations benefit.

• Dr Berkley is CEO of the Gavi Alliance.