Skeptical Raptor's Blog hunting pseudoscience in the internet jungle

HPV vaccinations reduces risk of cervical lesions

cervical-health-info-graphAnd more evidence that HPV vaccinations saves lives. Despite what Diane Harper says.

A study, published in the Journal of the National Cancer Institute, examined the rate of HPV related cervical abnormalities in vaccinated vs. unvaccinated women in Denmark. The study covered women reported information after the licensure of the HPV quadrivalent vaccine in 2006.

As a review, the HPV quadrivalent vaccine, also known as Gardasil (or Silgard in Europe). The vaccine prevents infection by human papillomavirus, a sexually transmitted disease, its subtypes 16 and 18 not only cause approximately 70% of cervical cancers, but they cause most HPV-induced anal (95% linked to HPV), vulvar (50% linked), vaginal (65% linked), oropharyngeal (60% linked) and penile (35% linked) cancers. The viruses are generally passed through genital contact, almost always as a result of vaginal, oral and anal sex.

The researchers identified all girls and women born in Denmark in 1989-1999 and obtained the corresponding HPV vaccination status in 2006-2012 for each individual, as well as information on incident cases of cervical lesions among those in the group. Risk of cervical atypia (abnormal cervical cells which have changed slightly, and the cells may return to normal by themselves or the changes may worsen) or worse (atypia+, ) and cervical intraepithelial neoplasia (or cervical dysplasia) grade 2 or 3 (CIN2/3) were statistically significantly reduced (emphasis mine) among vaccinated women born between 1991 and 1994 vs unvaccinated women.

Among women born between 1989 and 1990, the researchers observed a statistically significant reduced risk of atypia+ for vaccinated vs unvaccinated women. Additionally, they detected similar results for CIN2/3, but their findings here did not reach statistical significance. Furthermore, no cervical lesions were reported among girls born between 1997 and 1999.

The authors write, “In conclusion, our results show that vaccination with the quadrivalent HPV vaccine is already effective in reducing the risk for cervical precursor lesions at population level among young women in Denmark.” This type of result has been show shown in other population level studies.

So here we have more, population-based evidence that the HPV vaccine does what its supposed to do–HPV infection rates are significantly reduce in women who are properly vaccinated against the virus. One of the ignorant tropes of the antivaccination movement is that PAP smears would discover any HPV-related abnormality without the “dangerous” HPV vaccine. This ignores the following facts:

  1. The HPV vaccine has been shown to be extraordinarily safe in an epidemiological study of 200,000 girls, along with another study that included 300,000 women. These are huge studies that reviewed actual patient records in determining that there were no significant adverse events in these individuals after the HPV vaccine.
  2. The PAP smear can only diagnose a cervical abnormality AFTER the infection or cancer has occurred. Yes it can be treated, but an old adage of medicine, “a gram of prevention is better than a kilogram of cure.” In other words the costs, the risk of cancer even after diagnosis, and lack of resources to treat the diseases uncovered by the PAP smear far exceed the costs and nearly 0 risk of the HPV vaccine. 
  3. Of course, PAP smears have false-positives and -negatives which are both problematic.

It’s clear that the vaccine is safe. It’s clear that the vaccine prevents HPV. Anything else?

Visit the Science-based Vaccine Search Engine.

Key citations:

Comments (2)
Powered by WordPress 4.0.1
Don't forget to subscribe to this blog through any the services in the right sidebar.