Some HPV subtypes, such as HPV-6 and HPV-11, can cause warts around the genitals or anus, but have low (but not 0) risk of causing cancers. However, the higher risk subtypes, such as HPV 16 and 18, not only cause approximately 70% of cervical cancers, but they cause most HPV-induced anal (95% linked to HPV), vulvar (50% linked), vaginal (65% linked), oropharyngeal (60% linked) and penile (35% linked) cancers. HPV is estimated to be the cause of nearly 5% of all new cancers across the world.
According to the CDC, roughly 79 million Americans are infected with HPV–approximately 14 million Americans contract HPV every year. Most individuals don't even know they have the infection until the onset of cancer.
Are you now scared? Thanks to science, you might not have to be.
The HPV quadrivalent vaccine, also known as Gardasil (or Silgard in Europe) can prevent infection by human papillomavirus, substantially reducing the risk of these types of cancers. An HPV bivalent vaccine, known as Cervarix, is used in some countries, but only provides protection again two of the subtypes most associated with cervical 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.
Despite these ACIP recommendations, the CDC reported, in this week's Morbidity and Mortality Weekly Report, that only 57% of girls and 35% of boys, aged 13-17 years, have received at least one of the three recommended doses of the HPV vaccine. The vaccine uptake rate was developed from the CDC's National Immunization Survey-Teen (NIS-Teen), which determined vaccination information, via telephone survey, from adolescents aged 13-17 years across the USA. (By a show of hands, how many people reading about this survey wondered if antivaccination cultists were certain that the CDC was trying to identify unvaccinated children so that they could send in the black booted CDC Vaccination Shock Troops to force vaccines on poor little kids?) The goal of Healthy People 2020, the CDC's initiative to set clear objectives and strategies to improve the health of Americans, has set a goal that 80% of American teens have received all three doses of the HPV vaccine by 2020.
There is some good news. Even though the vaccine uptake rate is much lower than other vaccines, it is growing. From 2012-13, the vaccine update grew for girls from 53.8% to 57.3%–unfortunately, only a third had received the full three doses. On the other hand, vaccine uptake for teenage boys grew from 20.8% to 34.6% in the same period of time.
According to the lead author of the report, Shannon Stokley, assistant director for science at the CDC's Immunization Services Division, still believes that the 80% goal is still realistic:
The data on missed vaccination opportunities tells us that it is possible. When we look at the most recent cohort of girls that turned 13, 91% of them had a health care encounter where they could have started the HPV vaccine series before their 13th birthday. Also, 86% of 13-17 year-olds have received the Tdap vaccine. What these numbers tell us is that preteens and teens are getting to the doctor and they are getting vaccinated, but they aren't always receiving the HPV vaccine.The report also identified some reasons why uptake is so low:
- Given that 86% of this same group have received their Tdap vaccine, it's clear that these teenagers have regular encounters with their health care providers. One can only assume that physicians (or others) are not providing appropriate information about the HPV vaccine, including the cancer statistics. It's hard for me to ignore numbers, like 14 million Americans contracting HPV every year, which leads to significantly higher risk of some awful cancers, so physicians need to provide that data to their patients and their parents. The HPV vaccine should be near the top priority of immunizations given to teens.
- Parents are also part of the reason of the low vaccination rate against HPV. Many parents believe that their child isn't sexually active (which may or may not be true), but eventually they may become so. And even if one had a belief that their child will never have sex until she's married, with the high rate of sexual violence against men and women, contracting HPV could, in some cases, be unavoidable. Protecting your child with an effective and safe vaccine against a cancer causing disease is the wise choice.
Which leads me to one of the most important points in the article. The CDC and authors stress that, after reviewing and analyzing 8 years of post-licensure safety data, including studies that involved several hundred thousand to over a million teens, no serious safety concerns have been linked to the HPV vaccine since it became available. When you go looking for issues in epidemiological studies that include well over one million subjects, and you find no serious adverse effects, published the results for review, and the consensus from real scientists says "there are no serious adverse effects," then we've reached the point that there should be no hesitancy about the HPV vaccine.
Some of the antivaccine cult will go dumpster diving in the Vaccine Adverse Event Reporting System (VAERS), which is a program for vaccine safety, managed by the Centers for Disease Control and Prevention (CDC) and the Food and Drug Administration (FDA). VAERS functions as a post-marketing safety surveillance program (similar to other programs for almost every regulated medical device and pharmaceutical) which collects information about adverse events (whether related or unrelated to the vaccine) that occur after administration of vaccines.
VAERS has numerous limitations, including lack of scientifically designed questions, unverified reports, underreporting, inconsistent data quality, and absence of an unvaccinated control group. VAERS is basically a collector of information, but has limited value in making conclusions since it does not provide information that is obtained in a controlled manner. However, it does have some usefulness, in that certain trends may be spotted given enough time and data points.
I'll be a cheerleader here. Go get your kids vaccinated with Gardasil. It'll save their lives. It'll prevent cancer. And the vaccine is probably the best studied for adverse events, and there simply are no bad ones. None. None. None. Here is another vaccine that truly saves lives.
- Parkin DM. The global health burden of infection-associated cancers in the year 2002. Int J Cancer. 2006 Jun 15;118(12):3030-44. PubMed PMID: 16404738.
- 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.