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HPV vaccination effectiveness 'reduced in over-20s'

Immunising women aged 20 years or older against HPV infection is too late to offer adequate protection against genital warts, say researchers.

The study

Researchers in Sweden followed 2,209,263 females aged 10 to 44 years and collected information on HPV vaccinations from vaccination registers. Vaccine effectiveness was calculated using incident rate ratios of genital warts, which used a time to first event of genital warts as part of the analysis.

The findings

Vaccine effectiveness was highest in girls vaccinated before the age of 14, with an effectiveness of 93%. This dropped to 80% for girls vaccinated aged 14 to 16 years, 71% for girls vaccinated at 17 to 19 years and 48% for women vaccinated aged 20 to 22 years.

What does it mean for GPs?

The authors concluded that among women vaccinated at 20 years or older ‘there was low to immeasurable effectiveness and suggestive evidence that vaccinations tended to reach women at high genital warts risk.’ They added that it suggested ‘that vaccinations in this age group were not adequate for achieving the intended health benefit.’

Journal of the National Cancer Institute, online 13 March

Readers' comments (1)

  • As a paper published in Science and Engineering Ethics says, “Pharmaceutical companies fund the bulk of clinical research that is carried out on medications. Poor outcomes from these studies can have negative effects on sales of medicines. Previous research has shown that company funded research is much more likely to yield positive outcomes than research with any other sponsorship.” [1]

    Don't you think it would be interesting to note the percentage of studies done on the safety and efficacy of Gardasil that have been either funded by Merck Pharmaceuticals, that have at least one author that is a Merck employee, or both? If there is an exceedingly high number of such studies in comparison to 3rd party must ask whether there is a significant issue of bias involved.

    And, whether such studies actually amount to marketing on Merck pharmaceutical's behalf.

    Moreover, don't you agree that a HPV remedy might do more good in a world where there is no HPV pandemic, and where 90% of HPV infections go away without medical intervention of any kind?


    [1] Lexchin J. “Those Who Have the Gold Make the Evidence: How the Pharmaceutical Industry Biases the Outcomes of Clinical Trials of Medications.” Science and Engineering Ethics, February 15, 2011

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