Key Facts:

  • The two most common types of cervical cancer worldwide are both caused by HPV.
  • About $4 billion is spent annually managing HPV infections.
  • HPV vaccine is an anti-cancer vaccine.

What is HPV?

HPV is a very common virus that is sexually transmitted by direct contact with an infected person. In all, there are about 100 types of HPV that can infect the body, and of those 100 about 40 types can affect the genitals, the mouth and throat. Of these 40 types, 13 types are considered “high risk” for causing cervical cancer. The HPV vaccines protect against 9 of those types.

Approximately 80% of sexually active American women will have some form of HPV infection by age 50. Most people never know they have HPV, and some people may have more than one type of HPV.

So, if it’s so common, why the fuss? While there is still a lot to learn about HPV, we do know that it plays a major part in causing cervical cancer. Just two types of the virus (strains 16 and 18) are estimated to be responsible for 70% of cervical cancer. Globally there are about 500,000 new cases and 270,000 deaths each year from cervical cancer. The other 30% of cervical cancers are also associated with HPV strains.

Scientists are not able to isolate HPV in a culture and so infection is actually identified by the detection of HPV DNA from clinical samples.

There is no treatment for HPV. We can only treat the health problems that HPV causes, such as cancer through chemotherapy and surgery, or genital warts.

Why is it called “human” papillomavirus? Papillomaviruses occur in many species within the animal kingdom but the viruses are species specific. In the case of HPV, humans are the only reservoir for the virus.

The Vaccine

There are currently two HPV vaccines licensed for use in the U.S. Gardasil is approved for both males and females, but Cervarix is for females only. Both of these vaccines are very effective. So, after all 2 doses, 99% of recipients are protected against the 9 strains the vaccine covers.  The vaccines target the two high-risk HPVs, types 16 and 18, that cause the most cervical cancers.  Until very recently the vaccines only covered 4 strains.  Now they cover 9.

The two vaccines are made by using “virus-like particles,” a relatively new scientific development. These virus-like particles only look like the HPV virus; they don’t actually contain any RNA or DNA of the virus and are not able to cause an HPV infection.

Vaccination is recommended for all males and females 11 or 12 years old (up to 26 years) with 3 doses of HPV9. The second and third doses should be received 2 and 6 months after the first dose.

Getting the HPV vaccine is much safer than getting the diseases HPV can cause. But like any medications, an allergic reaction or adverse side effects may occur.

Adverse reactions to the vaccine include:

  • Soreness at injection site 20–90%  (of all the shots this one is a bit more painful)
  • Fever 10–13%
  • No serious adverse reactions have been (associated

Fainting (syncope) has been reported among adolescents who received HPV and the other vaccines recommended for this age group (Tdap, MCV). Recipients should always be seated during vaccine administration. Clinicians should observe persons for 15–20 minutes after vaccination. See more below.

Fainting and the HPV Vaccine

Fainting after a vaccine does happen and tends to happen more often in adolescents 11–18 years old. “Post-vaccination fainting has been most frequently reported after three adolescent vaccines (HPV, MCV4, and Tdap), based on VAERS data from January 1, 2005–July 31, 2007. However, we do not know whether the vaccines are responsible for the fainting or if the association with these vaccines simply reflects the fact that adolescents are generally more likely to experience fainting.” Often times people confuse fainting with seizures because the person may shake violently. More to come on that, hopefully, but for now the jury is still out.

Be assured that no one particular vaccine is more likely to cause fainting and there is no evidence that these fainting episodes have any long term consequences.  Fainting is more closely associated with these vaccines because they are the ones teens tend to get.

When is the best time to be vaccinated?

This was one of the sticking points for people when the vaccine first came out. The ideal time to give the vaccine would be before a person is potentially exposed to HPV through sexual contact. But even if a person has possibly been exposed to HPV they should still be vaccinated. Why? Because sexually active persons will still benefit if they have not been infected with all of the HPV vaccine types. The vaccine protects against four types of HPV, so they may receive some protection against the other types, even if they are exposed to one or more of the four high risk types.

Screening for HPV DNA or HPV antibody is not recommended prior to vaccination at any age.

We don’t know yet how long the vaccine provides protection. Studies so far do not show any waning of protection.  What we do know is that the immune response is greater the younger you get the vaccine.  That is one of the reasons it is recommended for 9 year olds.  There bodies do a better job of building an immune response.

Common Misconceptions

Cervical cancer isn’t that common, so we don’t really need the vaccine.

In 2010 (the most recent year numbers are available) 11,818 women in the United States were diagnosed with cervical cancer and 3,939 women in the United States died from cervical cancer. That’s almost four thousand moms, daughters, and grandmas. There are about 7000 HPV related cases of cancer that occur in men each year as well.

My pre-teen child does not need a vaccine against a STI (sexually transmitted infection aka STD).

The vaccine doesn’t cure HPV, so once you are exposed it’s too late to be protected by the vaccine. Vaccinating kids long before they become sexually active provides the greatest protection for them later in life. Because, and let’s be honest here, we really can’t predict when that will occur.

Remember, the HPV vaccine does not protect against all STIs. Safe sex practices are still recommended. If your family promotes abstinence for teens or until marriage, the vaccine protects them when that day comes.

It’s no secret that the pharmaceutical company Merck, which makes Gardasil, aggressively marketed the vaccine when it first came out and, in cases, led teens and young women to believe they were protected against all STIs. Shame. This set back uptake of the vaccine, which in turn caused missed opportunities for prevention.

Women who get the HPV vaccine do not need regular Pap tests.

The current vaccines do not protect against all HPV types and approximately 30% of cervical cancers will not be prevented by the vaccines. That is why it is important for women to continue getting screened for cervical cancer with regular Pap tests.

But wait, what about the argument for just getting regular Pap tests and not getting the vaccine? The Pap test only tells you if you have cervical cell changes. It doesn’t prevent them. The pain, inconvenience and cost of treating these abnormal Pap exams are much greater than the perceived risk of the vaccine. The HPV is a very safe vaccine.

It’s too late for the vaccine once someone is sexually active.

In an ideal world, the vaccine should be administered before potential exposure to HPV through sexual contact. It is possible that while being exposed to one of the many strains of HPV they may still benefit from the protection offered by the vaccine against the high-risk strains of the disease. Testing for the disease before getting the vaccine is not recommended.

 

Sources

History of Vaccines

Graph: Parkin DM (2006). “The global health burden of infection-associated cancers in the year 2002”. Int. J. Cancer 118 (12): 3030–44. doi:10.1002/ijc.21731. PMID 16404738.

Wittet S. & Tsu V. (2008). “Cervical cancer prevention and the Millennium Development Goals”. Bulletin of the World Health Organization 86 (6): 488–90. doi:10.2471/BLT.07.050450. PMC 2647477. PMID 18568279