I know that COVID-19 vaccines are our focus these days, but there is great news about cervical cancer rates in the UK in the decade since the HPV vaccine was first launched in 2008. Cervical pre-cancer incidence is down 88% since the UK’s devolved governments launched a school immunization program in 2008 to vaccinate all girls aged 12-13. They also launched a three-year catch-up program for girls aged 14-18.
These results are amazing and provide further evidence of the effectiveness of this vaccine in reducing cervical cancer rates.
mAs I always do, I will inform readers about HPV and HPV vaccines, then review the article that provides us with these results.
HPV and HPV vaccines
I know I cutting and pasting this section to every article I write about HPV vaccines.
However, I try to update this section when necessary with new information about either the disease or the vaccine. Moreover, there are new readers who want to know more about HPV, and this section can help someone get up-to-speed quickly. 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 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.
UK cervical cancer rates and HPV vaccination
In a study published in The BMJ in April 2021, researchers quantified the effect on cervical disease at age 20 years of immunization with the bivalent HPV vaccine at age 12-13 years in Scotland which screened women for cervical cancer from the age 20 (in 2016, it changed that to 25 in line with the rest of the UK.
The researchers had very detailed information about cervical cancer screening in the first cohort of fully vaccinated girls and of the girls in the catchup program.
Here are the key results:
- 138,692 records were analyzed. This is a large number, which provides us with better statistical measurements of the reduction of cervical cancer rates
- Compared with unvaccinated women born in 1988, vaccinated women born in 1995 and 1996 showed an 89% reduction of cervical intraepithelial neoplasia (CIN) grade 3 or worse, from 0.59% to 0.06%.
- An 88% reduction in CIN grade 2 or worse from 1.44% to 0.17%.
- A 79% reduction in CIN grade 1 from 0.69% to 0.15%.
- Importantly, younger age at the time of immunization was associated with increasing vaccine effectiveness: 86% for CIN grade 3 or worse for women vaccinated at age 12-13 compared with 51% for women vaccinated at age 17.
- Evidence of herd protection against high-grade cervical disease was found in unvaccinated girls in the 1995 and 1996 cohorts.
I hate to use this particular word, but these are awesome results. One of the anti-vaccine tropes about the HPV vaccine is that we have no data showing it actually reduces the rates of cervical cancer and pre-cancer. The 89% reduction CIN grade 3, the worst form of cervical pre-cancer.
In an accompanying editorial, Julia ML Brotherton, MD, wrote:
The findings are dramatic and document a considerable reduction in high grade cervical disease over time. The authors estimate a vaccine effectiveness of 86% (95% confidence interval 75% to 92%) for the most severe outcome of cervical intraepithelial neoplasia (CIN) grade 3 or worse in women fully vaccinated at ages 12-13 compared with the unvaccinated cohort. Notably, they report a large reduction in CIN grade 3 or worse in the most recent cohort of women compared with the pre-vaccination cohort, whether they were vaccinated or not (from a rate of 0.59% to 0.06%, an 89% decline), suggesting that interruption of HPV transmission in Scotland has created substantial herd protection.
This peer-reviewed research study has provided even more evidence of the effectiveness of the HPV in reducing cervical cancer and pre-cancer rates in young girls who received the HPV vaccine when they were 12-13 years old.
There are so few ways to prevent cancer, and the HPV vaccine is one of the best tools to prevent several dangerous cancers in men and women caused by the human papillomavirus.
- Brotherton JML. The remarkable impact of bivalent HPV vaccine in Scotland. BMJ. 2019 Apr 3;365:l1375. doi: 10.1136/bmj.l1375. PMID: 30944088.
- Palmer T, Wallace L, Pollock KG, Cuschieri K, Robertson C, Kavanagh K, Cruickshank M. Prevalence of cervical disease at age 20 after immunisation with bivalent HPV vaccine at age 12-13 in Scotland: retrospective population study. BMJ. 2019 Apr 3;365:l1161. doi: 10.1136/bmj.l1161. PMID: 30944092; PMCID: PMC6446188.