Ten years after the introduction of the human papillomavirus (HPV) vaccine in the USA in 2006, HPV prevalence has dropped significantly in a new study from the Centers for Disease Control and Prevention (CDC). This is very encouraging research that further strengthens the evidence behind the effectiveness of the HPV vaccine.
One of the tropes pushed by the anti-vaccine religion is that we don’t know if the vaccine actually will prevent an HPV infection after 10 years. Well, now we know.
Let’s take a look at the study on HPV prevalence in the USA.
All about HPV and HPV vaccines
I know I add this section to every article I write about HPV vaccines. It is updated almost every time with additional information about HPV or the vaccine. Moreover, there are readers who want to know more about HPV, and this section can help someone get up-to-speed quickly.
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 strain, 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 43,000 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 immunization 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 43,000 cancers a year in the USA alone. The HPV vaccine prevents becoming infected by HPV, which means you are protected from these cancers.
HPV prevalence study
In a presentation at the 2019 Epidemic Intelligence Service (EIS) conference, Nancy McClung, Ph.D., an EIS officer in the CDC’s National Center for Immunization and Respiratory Diseases, presented data from the National Health and Nutrition Examination Survey which evaluated HPV prevalence among 4,674 females in the prevaccine (2003–2006) and vaccine (2013–2016) eras overall. It also looked at prevalence by race and ethnicity.
Dr. McClung et al. found:
- For the cohort of females aged 14-19 years, 53.9% of females had received more than one dose of the HPV vaccine.
- For the same cohort, 52.6%, 58.1%, and 59.5% of non-Hispanic white, non-Hispanic black, and Mexican-American females respectively had received more than one dose of the vaccine.
- For the older cohort, 20-24 years, 51.5% had received more than one dose of the vaccines.
- For the same cohort, 58.5%, 45%, and 33.8% of non-Hispanic white, non-Hispanic black, and Mexican-Americans, respectively had received more than one dose of the vaccine.
- HPV prevalence decreased from 11.5% to 1.8%, or 86%, among females aged 14 to 19 years in the USA since the HPV vaccine was introduced in 2006.
- HPV prevalence decreased from 18.5% to 5.3%, or 71%, in women aged 20 to 24 years.
Summary
Once again, we find powerful data that HPV prevalence has been significantly reduced since the introduction of the HPV vaccine. As we know, reducing HPV prevalence leads to a reduction in the risk of HPV-related cancers.
Despite the relatively moderate uptake of the HPV vaccine, just over 50% (but it is increasing), it has had a massive impact on the reduction of HPV infections. Given the outstanding safety profile of the HPV vaccine, subsequent generations of young women and men can have a much lower risk of an HPV infection, thereby reducing the risk of HPV-related cancers.
Citations
- McClung NM, et al. Human papillomavirus prevalence among females in the United States, overall and by race/ethnicity, National Health and Nutrition Examination Survey, 2003–2006 and 2013–2016; Presented at: Epidemic Intelligence Service conference; April 29-May 2, 2019; Atlanta.
