The Benefits and Side Effects of the HPV Vaccine

Human papillomavirus (HPV) is an extremely common sexually transmitted infection—infecting about 80% of all sexually active people in the U.S. Most new HPV infections occur in teens and young adults who have no idea they have been infected, allowing them to pass the virus to their sexual partners without realizing it.

With no cure yet in sight, the best defense against HPV is vaccination. To this end, the Centers for Disease Control and Prevention (CDC) recommends that all children be vaccinated against HPV at ages 11 to 12, and even allows for vaccination up to age 45 for some people.

Learn more about the HPV vaccine—including recommendations and what to expect.

World immunization week and International HPV awareness day concept. Woman having vaccination for influenza or flu shot or HPV prevention with syringe by nurse or medical officer.
Pornpak Khunatorn / Getty Images

What Is HPV?

Human papillomavirus (HPV) is the most common sexually transmitted infection in the United States. So common, in fact, that nearly all sexually active adults will get it at least once in their lifetime if they aren’t vaccinated against the virus.

Roughly 13 million Americans are infected every year, and, while the majority of infections will clear up on their own without symptoms or consequence, some will lead to genital warts or cancer (most often cervical cancer in women and anal cancer in men who have sex with men).

About Gardasil-9

There are three HPV vaccines. They prevent anywhere from two to nine high-risk strains of HPV. These are the strains that are closely linked to the development of cancer.

Since 2016, Gardasil-9 has been the only one used in the U.S. It protects against HPV types 6, 11, 16, 18, 31, 33, 45, 52, and 58. Gardasil-9 is administered by injection in a 0.5 milliliter (mL) dose.

The other two vaccines—Cervarix and the original Gardasil—were voluntarily withdrawn from the U.S. market in favor of Gardasil-9.

Immunization Schedule 

The Advisory Committee on Immunization Practices (ACIP) recommends that everyone get vaccinated against HPV as part of routine vaccination starting at age 11 or 12 through age 26 years. That said, the vaccine can be given to anyone ages 9 to 45.

The number and timing of doses depend on when the first dose is given: 

  • For children 9 to 14: Two doses are administered six to 12 months apart.
  • For teens and adults 15 to 45: Three doses are administered over six months.

Adults over 26 who are interested in the HPV vaccine should discuss the benefits and limitations of vaccination with their healthcare provider. The vaccine is expected to be less effective in that group, as most people have been exposed to HPV by that age.

Differing from the CDC guidelines, the American Cancer Society (ACS) recommends HPV vaccination starting at age 9 to increase vaccination rates. ACS does not recommend HPV vaccination after 26.

Benefits

The biggest reason to be vaccinated against HPV is that it can protect you from getting a strain that may cause cancer or genital warts. The protection appears to be long-lasting, with studies suggesting a durable response of at least 10 years.

From 2012 to 2016, around 44,000 HPV-associated cancers occurred in the United States, including nearly all cervical and anal cancers and most cases of penile, vaginal, and vulvar cancer. Studies have also shown that around 70% of oropharyngeal cancers may be linked to HPV; many of these cancers may be caused by a combination of this virus, tobacco use, and alcohol use.

While Gardasil-9 doesn’t protect against all strains of HPV, it does protect against the strains most likely to cause cancer. Among them, HPV types 16 and 18 account for around 70% of all cervical cancers.

According to the CDC, widespread HPV vaccination in children could prevent 92% of all HPV-related cancers in the United States, translating to a reduction of 32,000 cancer cases per year.

Side Effects 

As with any vaccine, Gardasil-9 may cause side effects. Most are temporary and almost always mild. The most common include:

  • Injection site redness, swelling, or soreness
  • Mild fever
  • Dizziness or lightheadedness
  • Nausea
  • Headache 
  • Fatigue 
  • Body aches

Although an allergic reaction is possible, severe reactions (including anaphylaxis) are extremely rare.

When to Call 911

If you suspect you or someone else may be experiencing an anaphylactic reaction, seek medical care immediately. Signs and symptoms of anaphylaxis after getting Gardasil-9 include:

  • Rash or hives
  • Dizziness
  • Rapid heartbeats or palpitations
  • Nausea or vomiting
  • Shortness of breath
  • Wheezing
  • Swelling of the mouth, tongue, or throat
  • A feeling of impending doom

If left untreated, anaphylaxis can lead to shock, coma, or even death.

Precautions and Contraindications

While nearly everyone can safely receive the HPV vaccine, there are some who shouldn’t. According to the CDC, you should not receive Gardasil-9 if:

  • You have had a life-threatening allergic reaction to the HPV vaccine or any component of the vaccine in the past. Gardasil-9 is produced in Saccharomyces cerevisiae (baker’s yeast) and is contraindicated for persons with a history of immediate hypersensitivity to yeast.
  • You are moderately or severely sick (in which case, you should wait until you recover before getting vaccinated).
  • You are pregnant. HPV vaccine is not recommended for pregnant women. However, if you're found to be pregnant after starting the HPV vaccine series, there should be no cause for worry. Still, any additional doses should be delayed until you are no longer pregnant. 

You can still get Gardasil-9 even if you’ve tested positive for HPV, as it may protect against other HPV strains. 

Ensuring Vaccine Safety

Before a vaccine is approved by the U.S. Food and Drug Administration (FDA), it is tested in thousands of people during clinical trials to verify its safety and efficacy.

There are also systems in place to monitor for safety and efficacy once a vaccine like Gardasil-9 is introduced to the American marketplace. These include:

  • Vaccine Adverse Event Reporting System (VAERS): A reporting system used by the CDC and FDA for research and surveillance purposes that allows anyone to report adverse events following vaccination  
  • Vaccine Safety Datalink (VSD): A group of healthcare organizations that conducts studies to see if specific side effects are linked to a particular vaccine
  • Clinical Immunization Safety Assessment (CISA) Network: A group of vaccine safety experts and organizations established by the CDC that studies safety issues following the introduction of a vaccine 

When these systems flag a potential adverse event, the ACIP reviews the evidence and adjusts their recommendations if needed.

HPV Vaccination and Fainting Risk

After Gardasil-9 was released in 2016, reports of syncope (fainting) prompted the ACIP to issue recommendations that people sit or lie down for 15 minutes after receiving the vaccine to prevent falls or injuries. 

A Word From Verywell 

If you or your child has had any adverse reaction to a vaccine in the past, let your healthcare provider know before getting Gardasil-9. This shouldn't suggest you need to avoid the vaccine but rather that your condition be monitored after the vaccination. In the majority of cases, the benefits of HPV vaccination outweigh the risks.

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Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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