What to Know About Gardasil 9

Only Vaccine Approved for Human Papillomavirus (HPV) in the US

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Gardasil 9 is a vaccine used to prevent human papillomavirus (HPV) infection. It specifically protects against nine high-risk strains of HPV associated with genital warts and certain cancers, including cervical cancer.

It replaced an early version of the vaccine (Gardasil 4) in 2017, which protected against four high-risk types.

Young doctor giving a patient injection.
Foremniakowski / Getty Images

Gardasil 9 is a recombinant vaccine made through genetic engineering. It uses a small piece of viral DNA to "teach" yeast cells how to produce viral surface proteins. When injected into the body, these harmless proteins stimulate the production of defensive antibodies that ward off infection.

Gardasil 9 is given by intramuscular injection (into a large muscle) in a series of two or three doses depending on a person's age.

With the discontinuation of Cervarix (an HPV vaccine that protected against high-risk types) in 2016, Gardasil 9 is today the only HPV vaccine approved for use by the U.S. Food and Drug Administration (FDA).

Uses for Gardasil 9

HPV is a group of around 200 similar viruses, more than 40 of which are sexually transmitted.

Among the sexually transmitted variants, some are known to cause genital warts, while others are strongly linked to cervical cancer, anal cancer, penile cancer, vaginal cancer, vulvar cancer, and head and neck cancers.

HPV is so common that nearly all women and men will get it at some point in their lives. According to the Centers for Disease Control and Prevention (CDC), nearly 80 million people are currently infected in the United States, while an estimated 14 million are infected each year.

Even so, the majority of HPV infections will clear on their own with no long-term consequence, while only a small handful will progress to cancer. Gardasil 9 aims to prevent HPV infection so that this doesn't occur.

Gardasil 9 protects against nine high-risk types of HPV, two of which cause genital warts (types 6 and 11) and seven of which are linked to cancer (types 16, 18, 31, 33, 45, 52, and 58).

According to the CDC, HPV is responsible for more than 90% of cervical and anal cancers, 70% of vaginal and vulvar cancers, and 60% of penile cancers. HPV types 16 and 18 account for the majority of these.

Vaccination Recommendations

Gardasil 9 is approved by the FDA for use in people ages 9 through 45. With that being said, the strength of the recommendations varies by age group.

Ages 9 to 26

In the United States, vaccination recommendations are issued by a group of experts within the CDC called the Advisory Committee on Immunization Practices (ACIP). The committee currently recommends Gardasil 9 vaccination in the following groups:

  • All girls and boys ages 11 to 12 years
  • Children as young as 9 who may be at risk of exposure to HPV
  • People 13 to 26 who have not been vaccinated or completed the vaccine series

Because the HPV types protected by Gardasil 9 are sexually transmitted, the ACIP recommends vaccination at a younger age before people are usually sexually active.

Moreover, multiple studies have shown that two doses of the vaccine given to 9- to 14-year-olds provide better antibody response than three doses given to older adolescents or young adults.

Ages 27 to 45

Despite the FDA approval, the ACIP does not recommend routine vaccination in adults 27 to 45 years of age.

A healthcare provider may, however, recommend the vaccine to some patients based on their sexual history. The decision to proceed is shared between practitioner and patient.

Before Getting Gardasil 9

Before getting this or any vaccine, it's important to tell your healthcare provider about any conditions you are managing and medications you are taking.

There are few contraindications to the use of Gardasil 9. The only absolute contraindication is a prior severe hypersensitive reaction to the vaccine or a prior severe allergic reaction to yeast.

Symptoms of severe drug hypersensitivity include:

  • Rapid onset of hives
  • Trouble breathing
  • Tightening of the throat
  • Rapid heartbeat
  • Nausea or vomiting
  • Fainting

If you experience a severe reaction to Gardasil 9, you should not receive another dose.

If you or your child is immunocompromised, you need to let your healthcare provider know. This includes anyone with HIV, as well as organ transplant recipients, children with primary immunodeficiency (PID), or anyone undergoing any immunosuppressive therapy, such as:

Being immunocompromised or using these therapies doesn't prevent you from being able to get Gardasil 9 or put you at any special risk if you do. However, it does mean that your immune response may be blunted, undermining the effectiveness of the vaccine.

Finally, Gardasil is not recommended during pregnancy. According to the CDC, the vaccine has not been shown to increase the risk of birth defects and miscarriages, but more research is still needed.


Gardasil 9 is available either in single-use vials or single-use pre-filled syringes. Each dose, administered by a healthcare professional, contains 0.5 milliliters (mL) of the vaccine.

The injection is most often delivered to the deltoid muscle of the shoulder but can also be delivered to the upper and outer portion of the front of the thigh (also known as the anterolateral thigh).

The recommended dosage varies by a person's age or immune status.

Age  Doses Timing
9 to 14 years 2 The second dose is given six to 12 months after the first dose.
•15 to 45 years
•Immunocompromised children 9 to 14 years
3 The second dose is given one to two months after the first dose. The third dose is given six months after the first dose.

If you are immunocompromised and under age 15 (and, therefore, are not yet due for your third dose), you may need an extra dose ahead of schedule to ensure a more robust immune response.

Side Effects

Side effects are common with all vaccines, although those associated with with Gardasil 9 tend to mild and resolve on their own within a day or so. On rare occasions, severe complications have been known to occur.


There are several side effects commonly experienced by people who receive Gardasil 9. Females tend to be affected more than males. These side effects include:

  • Injection site pain
  • Injection site swelling
  • Injection site redness
  • Headache

Mild fever, diarrhea, fatigue, and stomachache have also been reported, albeit less commonly.

Fainting (syncope) has been known to occur in some immediately after the injection. This is usually passes quickly. Even so, anyone given Gardasil 9 should be monitored for 15 minutes after receiving a dose to be safe.

If lightheadedness occurs, the person should be seated with their head placed between their legs until the feeling passes.


Severe reactions are rare with Gardasil 9. Arguably, the greatest concern is the risk of drug hypersensitivity. This can affect people with no history of allergy.

Still, anaphylaxis—a potentially life-threatening whole-body reaction—is rarely seen with Gardasil-9. According to the World Health Organization, this reaction occurs at a rate of only 1.7 cases per million doses of the HPV vaccine.


Gardasil can greatly reduce the risk of genital warts and certain cancers, but that doesn't necessarily mean they won't develop. This is especially true if you are vaccinated later rather than earlier. Moreover, not all genital, anal, or oral cancers are caused by HPV.

A 2018 review in the Journal of Infectious Diseases reported that Gardasil 9 has the potential to prevent around 90% of cervical cancers and HPV-related vulvar, vaginal, and anal cancers.

As impressive as these findings are, they shouldn't suggest that you can avoid or delay recommended cancer screenings, including Pap smears, or pay any less attention to signs and symptoms of cancer.

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12 Sources
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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