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Most of the deaths from cervical cancer occur in developing countries, particularly among the lower socio-economic classes. Cancer prevention programs are very weak or non-existent in many poor nations due to financial constraints.
Two new vaccines can prevent this cancer -- Gardasil and Cervarix -- and should be made available at affordable prices so the needy can be immunized. The current cost of around US$360 for these vaccines is too high in countries where half the population lives below the poverty line.
The World Health Organization, the Program for Appropriate Technology in Health, Harvard University and the International Agency for Research on Cancer are working on this, with funding from the Bill and Melinda Gates Foundation. Countries might have to consider public-private partnerships to develop the vaccine locally and cheaply.
Acceptability of the vaccine within local communities can also be a hurdle that prevents immunization. The vaccine is effective only if given before there is any contact with the human papilloma virus, which is transmitted sexually. The target age group for vaccination is 11 to 16 years, or even younger, which might be a problem in certain societies. The vaccine has already aroused fears that it might encourage promiscuous behavior. However, studies conducted in some developing countries, like Vietnam, have found widespread acceptance as it is being promoted as a vaccine that prevents cancer.
So far, the vaccines offer protection against only two types of cancer-causing viruses, known as HPV types 16 and 18, which are the cause of 70 percent of cervical cancers. So, even if the vaccine offers total protection, the vaccinated population will still be vulnerable to the other types of HPV that are responsible for the remaining 30 percent of cancers. Regular screening by PAP smears should therefore continue just as before vaccination for early detection and treatment of cancer.
Cervical cancer is usually seen about 20 years after an HPV infection. Thus, the predicted decrease in the prevalence of the cancer will be visible only a few decades after vaccination. Until then, cervical screening programs must continue just as before, concurrent to the vaccination program. It is also not known at present how long the immunity offered by the vaccine will last. It might begin to wane after some years. Perhaps boosters will be required. Further studies are pending in this area. Until then, once again, one has to rely on intensive screening programs for early detection of the cancer.
In the past few decades, the prevalence of cervical cancer has come down dramatically in the developed nations, owing to extensive screening programs. But, developing countries continue to show increasing number of cases due to inadequate screening. A paucity of pecuniary resources is the most significant factor here. Providing vaccinations and screening together means an additional strain on the already insufficient health funds. There is a need to develop novel and affordable alternatives to the existing expensive practices.
The HPV vaccine has a strong potential for preventing millions of deaths. But for this to become a reality, the statistics in the developing countries need to change. The biggest hurdle in these nations is the financial situation. Once every vulnerable woman in these poor nations has easy and affordable access to the vaccine, we can look forward to a world where fewer women are dying of cervical cancer.
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(Dr. Pradnya Kulkarni is a clinical pathologist based in Pune, India.)
