HPV vaccine efficacy – another study shows long-term immunogenicity

As I’ve mentioned dozens of times, the anti-vaccine religion probably hates the HPV vaccine more than all others put together. They’ve invented numerous myths and tropes about the HPV vaccine, all without any foundation in science. One of these claims is that we don’t know anything about long-term HPV vaccine efficacy.

Of course, the HPV vaccine is a relatively new one, so long-term data requires us to wait for time to pass. Fortunately, we are accumulating a boatload of data that shows us that the long-term HPV vaccine efficacy is pretty strong.

And now, we have a powerful new study from Finland that shows that after 12 years post-vaccination, anti-HPV immunogenicity remains quite high. Let’s take a look.

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 vaccine efficacy – Finnish study

In a paper published in the Journal of Infectious Diseases by Hanna Artemchuk of the Karolinska Institutet, the researchers took blood samples of about 1100 Finnish females who participated in phase III clinical trials. They then tested the serum for HPV-specific antibodies.

They determined that the HPV antibody levels for the HPV16 and HPV18 subtypes remained stable for up to 12 years post-vaccination. In other words, a decade after receiving the vaccines, these Finnish girls still are immunized against two of the more serious subtypes of HPV.

The researchers concluded that:

The stability of vaccine-induced antibody levels is in accordance with the high long-term protection reported previously. The differences in antibody levels induced by the two vaccines imply that continued follow-up to identify possible breakthrough cases and estimation of the minimal protective levels of serum antibodies is a research priority.

Summary

This paper was short and to the point – it provided evidence that supports long-term HPV vaccine efficacy. And it defeats the old trope about Gardasil that “we don’t know how long it works.” Along with other epidemiological evidence that supports long-term effectiveness, we have very convincing evidence that the HPV vaccine prevents cancer.

I know anti-HPV vaccine myths persist because, in absence of actual facts, the anti-vaccine zealots will continue to invent stories about the vaccine. But really, what reasons to avoid the vaccine still hold merit?

Citations

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!