I enjoy repeating myself about the HPV vaccine, but another systematic review says it is effective in preventing HPV infections. And when we can prevent HPV infections, we can prevent a long list of cancers.
I know some of you think that your blueberry kale smoothies prevent cancer, but there are really only a handful of ways to prevent cancer. The HPV vaccine is one of the most effective methods to prevent cancer.
Let’s review HPV, the HPV vaccine, and this new systematic review.
All about HPV and HPV vaccines
I know I cut and paste this section to every article I write about HPV vaccines, but it’s the first step to HPV vaccine myth debunking. Some readers may be coming here for the first time, and they ought to know just how the HPV vaccine prevents cancer.
However, I try to update this section when necessary with new information about either the disease or the vaccine. If you’ve read this section 47 times, just skip down to the next section where I discuss the key point of this article.
Genital and oral human papillomavirus (HPV) infections are the most common sexually transmitted infections (STI) in the USA. HPV is generally transmitted from personal contact during vaginal, anal, or oral sex.
It’s important to note that there are more than 150 strains or subtypes of HPV that can infect humans – however, only 40 of these strains are linked to one or more different cancers. Of those 40 strains, most are fairly rare.
Although the early symptoms of HPV infections aren’t serious and many HPV infections resolve themselves without long-term harm, HPV infections are causally 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:
In addition, there is some evidence that HPV infections are causally linked to skin and prostate cancers. The link to skin cancer is still preliminary, but there is much stronger evidence that HPV is linked to many prostate cancers.
HPV is believed to cause nearly 5% of all new cancers across the world, making it almost as dangerous as tobacco in that respect. 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. The CDC also states that over 46,000 HPV-related cancers are diagnosed in the USA every year. It may be several times that amount worldwide.
There were two HPV vaccines on the world market before 2014. GSK, also known as GlaxoSmithKline, produced Cervarix, a bivalent (protects against two HPV strains) vaccine. It has been withdrawn from the US market (although available in many other markets), because of the competition from the quadrivalent (immunizes against four different HPV strains) and 9-valent (against nine HPV strains) Gardasil vaccines.
Merck manufactures Gardasil, probably the most popular HPV vaccine in the world. The first version of the vaccine, quadrivalent Gardasil, targets the two HPV genotypes known to cause about 70% of cervical cancer and two other HPV genotypes that cause genital warts. In Europe and other markets, Gardasil is known as Silgard.
The newer Gardasil 9, approved by the FDA in 2014, is a 9-valent vaccine, protecting against HPV types 6, 11, 16, 18, 31, 33, 45, 52, and 58. It targets the four HPV strains found in the quadrivalent version, along with five additional ones that are linked to cervical and other HPV-related cancers. Both versions of Gardasil are prophylactic, meant to be given to females or males before they become exposed to possible HPV infection through intimate contact.
Gardasil is one of the easiest and best ways to prevent a few dangerous and, to abuse the definition slightly, common cancers that afflict men and women. Without a doubt, the HPV vaccine prevents cancer.
Currently, in the United States, the Advisory Committee on Immunization Practices (ACIP) recommends that preteen girls and boys aged 11 or 12 are vaccinated against HPV. The vaccine is also recommended for teenage girls and young women up to the age of 26 who did not receive it when they were younger, and teenage boys and young men up to the age of 21.
Let me sum this all up so that if you come away from this section with nothing else, you get this summary. HPV is a sexually transmitted disease. HPV causes 46,000 cancers a year in the USA alone. The HPV vaccine prevents becoming infected by HPV, which means you are protected from these cancers.
A systematic review says HPV vaccine is effective
In a systematic review (considered to be the top of the hierarchy of biomedical research) published on 4 November 2022 in Expert Review of Vaccines, the authors reviewed 138 peer-reviewed publications reporting HPV vaccine impact or effectiveness. The review only included the quadrivalent HPV vaccine and did not include Gardasil9, as it has only been recently available worldwide. The outcomes of interest included rates of infection at different anatomical sites and incidence of several HPV-related disease endpoints.
The systematic review detailed the impact and effectiveness of GARDASIL through immunization programs in 23 countries across Africa, Asia, Europe, Australia, South America, and North America. It builds on a prior review of real-world data published in 2016.
The researchers published the following results:
- This review captures the recent 5 years’ publication of the real-world impact and effectiveness of human papillomavirus (HPV) vaccines in females and males, which represent at least a 14-year follow-up real-world impact and effectiveness since the launch of the quadrivalent vaccine in 2006.
- Data identified demonstrate statistically significant decreases in vaccine-type HPV genital, oral and anal infections, and prevention of recurrent respiratory papillomatosis, anal, and cervical lesions.
- There is now robust and expansive data available to support HPV vaccination direct and indirect benefits from a variety of settings and populations including different countries, different outcome assessments, and different vaccination program strategies.
This review of the robust literature clearly shows that the HPV vaccine is effective in preventing HPV infections in both women and men. And it shows a solid herd effect, which further reduces the risk of HPV infection.
I know that most of you know that the HPV vaccine is both safe and effective. But I don’t mind piling on with more and more science, and this study confirms that the HPV vaccine is extremely effective.
- Wang WV, Kothari S, Skufca J, Giuliano AR, Sundström K, Nygård M, Koro C, Baay M, Verstraeten T, Luxembourg A, Saah AJ, Garland SM. Real-world impact and effectiveness of the quadrivalent HPV vaccine: an updated systematic literature review. Expert Rev Vaccines. 2022 Nov 4:1-19. doi: 10.1080/14760584.2022.2129615. Epub ahead of print. PMID: 36178094.