Delving Deeper
Brotherton JM, Bloem PN, Population based HPV vaccination programs are safe and effective: 2017 update and the impetus for achieving better global coverage Best Practice & Research Clinical Obstetrics & Gynaecology (2017) [see source]
This chapter in a forthcoming book provides the most up-to-date overview of HPV vaccination programs around the world, including data on HPV vaccination coverage for 82 countries. It contains lots of medical terms, but the takeaways are clear:
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HPV causes cervical cancer (as well as some other less common cancers)
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The first HPV vaccine was registered in 2006, preventing 2 strains of HPV (16 and 18), which account for over 70% of cervical cancers;
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Since then, two more vaccines have been released, one covering 4 strains (16, 18, 6 and 11) and more recently one covering 9 strains.
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The vaccine is safe. Over 270 million doses have been given in the past 11 years. The vaccine has been studied intensively. The Global Advisory Committee on Vaccine Safety has regularly reviewed global data about HPV vaccine safety and seven times has publicly declared that the vaccines are safe, most recently in June 2017.
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The vaccine seems to last – so far there is no evidence that boosters are needed.
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The vaccine works better than expected. There seems to be some “cross-protection” from the 2 strain HPV vaccine, which means that it offers some protection against some of the other strains as well.
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Evidence is coming in from numerous countries of how vaccination has led to sharp falls in the percentage of young people with the HPV strains which cause cervical cancer. This graph shows how the incidence of HPV infection among 20-year old Scottish women fell by 80-90% between 2008 and 2015 as a result of the vaccine.
Percentage of 20-year old women diagnosed with CIN 2/CIN 3+ by birth cohort year
Source: https://www.hse.ie/