Unless you’re a noobie to this blog and website, you probably know I’m a big proponent of the human papillomavirus (HPV) anti-cancer vaccine, usually known as Gardasil or Cervarix. And now we have more evidence that the HPV vaccination schedule has caused a significant drop in HPV infection rates in teens.
HPV is the most common sexually transmitted infection (STI) in the USA. There are more than 40 HPV sub-types that can infect the genital areas of males and females. Additionally, some HPV types can also infect the mouth and throat. HPV is generally transmitted from personal contact during vaginal, anal or oral sex.
HPV is linked to many dangerous cancers in both men and women, such as penile, cervical, anal, mouth and throat cancers. In fact, HPV is believed to cause nearly 5% of all new cancers across the world, making it almost as frightening as tobacco for causing cancer.
Because HPV is so prevalent in adults, blocking the infection in pre-teens, teens and young adults can eventually lower the cancer rate for all HPV-related cancers. Maybe one day, it can be wiped out, like many other infectious diseases just through vaccination.
The evidence that Gardasil and the HPV vaccination schedule are safe and effective is almost overwhelming. Sure, there are a few myths here and there about the vaccine that require occasional debunking. However, there are so few methods to actually prevent cancer – the HPV vaccine, by blocking HPV infections, is one of the best methods to prevent some of the nastiest cancers.
HPV vaccination schedule – infection rates
A study, recently published in Pediatrics, by Dr. Lauri Markowitz and her colleagues, provided strong evidence that the HPV vaccination schedule is directly linked to a reduction in HPV infections.
Dr. Markowitz investigate the rates of HPV infection among teens in the USA after introduction of the HPV vaccine. She found that the infection rate, in teens aged 14 to 19, dropped by 64% in the six years after the vaccine was added to the recommended vaccination schedule. Furthermore, the infection rate dropped by 34% among people ages 20 to 24.
In case you’re asking, there is simply no evidence that the decline was caused by a sudden nationwide teen celibacy increase. Of course, there is just no link between sexuality and the HPV vaccine, so there’s that.
The evidence is actually more interesting, because this decline in HPV infection rates is observed despite a relatively low uptake of the vaccine. By 2013, around 38% of US girls had received all three doses of the HPV vaccines, while only 57% had received at least one dose. The number is lower for boys, around 35%, because the vaccine was recommended for boys later than for girls.
So despite the moderate level of HPV vaccine coverage, there has been a dramatic reduction in the HPV infection rate. There might be a couple of possible explanations for this result:
- First, there is evidence that even one dose of Gardasil may be effective in providing protection against HPV.
- Second, a herd immunity may actually be forming that keeps the virus from spreading. For example, there is evidence from Australia, which provided the vaccine for free to girls – the results showed significantly large declines in HPV infection rates in boys as well.
Although these results are exciting and firmly support the hypothesis that the HPV vaccination schedule is reducing the rate of HPV infection, we still need to wait to gather evidence to support the hypothesis that the vaccine will lead to a lower cancer rate. Some studies are already showing drops in the rates of precancerous lesions in the cervix after widespread implementation of an HPV vaccination schedule in Scotland, so the link between reducing HPV infection and HPV related cancers is coming into focus.
And, there is more good news. According to a recently published survey, 60% of pediatricians and 59% of family physicians were strongly recommending the HPV vaccine for girls. Moreover, 52% and 41% of pediatricians and family physicians, respectively, were strongly recommending the vaccine to boys.
We’re getting close to forming a wall against HPV in the USA and other countries that have a growing uptake of the HPV vaccine.
Vaccinate your girls and boys against HPV, it will prevent cancer in the future. And if you’re a young adult, discuss getting the vaccine with your physician. Except for a few very rare exceptions, the vaccine is free in the USA, especially for teens. In other countries, like Australia and the UK, the vaccine is almost entirely free (or mostly so).
Gardasil prevents cancer. And it saves lives.
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- Allison MA, Hurley LP, Markowitz L, Crane LA, Brtnikova M, Beaty BL, Snow M, Cory J, Stokley S, Roark J, Kempe A. Primary Care Physicians’ Perspectives About HPV Vaccine. Pediatrics. 2016 Jan 4. pii: peds.2015-2488. [Epub ahead of print] PubMed PMID: 26729738.
- Markowitz LE, Liu G, Hariri S, et al. Prevalence of HPV After Introduction of the Vaccination Program in the United States. Pediatrics. 2016;137(2):e20151968
- Pollock KG, Kavanagh K, Potts A, Love J, Cuschieri K, Cubie H, Robertson C, Cruickshank M, Palmer TJ, Nicoll S, Donaghy M. Reduction of low- and high-grade cervical abnormalities associated with high uptake of the HPV bivalent vaccine in Scotland. Br J Cancer. 2014 Oct 28;111(9):1824-30. doi: 10.1038/bjc.2014.479. Epub 2014 Sep 2. PubMed PMID: 25180766; PubMed Central PMCID: PMC4453734.
- Stokley S, Jeyarajah J, Yankey D, Cano M, Gee J, Roark J, Curtis RC, Markowitz L; Immunization Services Division, National Center for Immunization and Respiratory Diseases, CDC. Human papillomavirus vaccination coverage among adolescents, 2007-2013, and postlicensure vaccine safety monitoring, 2006-2014 – United States. MMWR Morb Mortal Wkly Rep. 2014 Jul 25;63(29):620-4. PubMed PMID: 25055185.