Gardasil prevents cancer – evidence for oral cancer protection

According to recent studies from the CDC, only about 63% of teen girls and 50% of teen boys have started the HPV vaccination series. The relatively low vaccine uptake, despite the evidence that Gardasil prevents cancer, one of the few ways to actually prevent cancer, is especially frustrating to those of us who are supporters of the vaccine. However, new data that Gardasil prevents cancer may drive acceptance for the vaccine – new research appears to show that the HPV vaccine may protect against head and neck cancers.

Gardasil 9, the most current version of the vaccine, was approved to protect against cervical, vulvar, vaginal, and anal cancers in females along with anal cancers in males – if it is also shown to prevent oropharyngeal cancers (and eventually gets new indications after FDA review), maybe that can increase the lagging HPV vaccination rates.

All about HPV and the cancer preventing vaccine

I know, I’ve written about this vaccine 100 times, so you’ve read these paragraphs enough to quote them without looking. Actually, I change it up with new information frequently.

However, for some of you, this might be your first bit of research into the human papillomavirus (HPV) vaccine, so it’s important to get a brief overview of HPV and the vaccines. If you’ve read this before, just skip to the next section if you want.

Genital and oral  HPV are the most common sexually transmitted infections (STI) in the USA. There are more than 150 strains or subtypes of HPV that can infect humans, although only 40 of these strains are linked to a variety of cancers. HPV is generally transmitted from personal contact during vaginal, anal or oral sex.

Although the early symptoms of HPV infections aren’t serious, those infections are closely linked to many types of cancers in men and women. According to current medical research, here are some of the cancers that are linked to HPV:

These are all dangerous and disfiguring cancers that can be mostly prevented by the HPV cancer vaccine. If you’re a male, and you think that these are mostly female cancers, penile cancer can lead to amputation of your penis. Just think about that guys.

HPV is believed to cause nearly 5% of all new cancers across the world, making it almost as dangerous as tobacco with respect to cancer. According to the CDC, roughly 79 million Americans are infected with HPV–approximately 14 million Americans contract a new HPV every year. Most individuals don’t even know they have the infection until the onset of cancer. About 27,000 HPV-related cancers are diagnosed in the USA every year.

There were two HPV vaccines on the market before 2014. GSK, also known as GlaxoSmithKline manufactured Cervarix, a bivalent vaccine, but it has been withdrawn from the US market, because of the competition from the other HPV vaccines. In Europe and other markets, Gardasil is known as Silgard.

Merck manufactures the other HPV vaccines. Its first vaccine, the quadrivalent Gardasil, targets the two HPV genotypes known to cause about 70% of cervical cancer and two other HPV genotypes that cause genital warts. The newer Gardasil 9, approved by the FDA in 2014, is a 9-valent vaccine. It targets the four HPV genotypes in the quadrivalent version, along with five additional ones that are linked to cervical and other types of cancer. Both versions of Gardasil are prophylactic, meant to be given before females or males become exposed to possible HPV infection through intimate contact.

Gardasil prevents cancer – new study

A study, to be presented at the American Society of Clinical Oncology meeting in June 2017, suggests that Gardasil may protect against head and neck cancers. It found an 88% reduction in oral infections (which, if they are HPV related, are an important risk factor for these cancers) for those who were vaccinated with Gardasil.

Maura Gillison MD PhD of the MD Anderson Cancer Center in Houston, TX, the lead researcher, and her team analyzed data from the National Health and Nutrition Examination Survey (NHANES). This was a survey conducted by the National Center for Health Statistics designed to assess the health and wellness of the U.S. population. Since 2009, Gillison and her team have worked with NHANES to examine oral HPV infections along with the effect of Gardasil on its incidence.

This study relied upon data from 2011-2014. Participants in the survey self-reported whether they had received one or more HPV vaccines. Her study compared HPV infection rates between those who received a shot of an HPV vaccine and those who did not, out of a group of 2,627 young adults aged 18 to 33.

The researchers observed that the oral infection rates in the vaccinated group was about 88% lower than those individuals who were not vaccinated. Moreover, the investigators actually found no infections in vaccinated males, which would suggest that Gardasil may reduce the prevalence of those infections by as high as 100%. HPV-related head and neck cancers disproportionately affect males, so this data may be important in increasing Gardasil vaccination rates in males.

Now it’s important to note that this type of study cannot establish a causal relationship between the vaccine and lowered incidence of HPV infections. In addition, this study is being presented at a scientific meeting, which has only cursory peer review, placing it way down the hierarchy of biomedical studies. A clinical trial, like those used to establish the efficacy of Gardasil for other types of HPV infections, would be necessary to establish a causal relationship.

However, this research does give us some preliminary evidence that Gardasil is much more effective than originally described, and there’s nothing wrong with that.

Summary

Now, let’s be clear – there is overwhelming evidence that Gardasil prevents cancer, especially cervical, vulvar, vaginal, and anal cancers. Now we have new evidence that Gardasil may prevent head and neck cancers, which are more prevalent amongst males, though still a large risk factor for females.

Again, there are only a handful of ways to actually prevent cancer. Why should you or your children get vaccinated against these cancers? It’s obvious – Gardasil prevents cancer.

Editor’s note – this article has been updated to fix some broken links and formatting issues. And to fix an egregious error in the spelling of the name of the primary researcher. Sorry Dr. Gillison. 

The Original Skeptical Raptor
Chief Executive Officer at SkepticalRaptor

Lifetime lover of science, especially biomedical research. Spent years in academics, business development, research, and traveling the world shilling for Big Pharma. I love sports, mostly college basketball and football, hockey, and baseball. I enjoy great food and intelligent conversation. And a delicious morning coffee!