Gardasil 9 is a vaccine (immunization) that protects against human papillomavirus (HPV). Gardasil side effects are not common and are usually mild. For example, some people may experience soreness, redness, or swelling at the injection site.

HPV vaccination prevents nine high-risk types of HPV linked to cancer, predominately cervical cancer but also cancer of the anus, vagina, vulva, penis, mouth, tonsils, and throat. The safety of Gardasil was established in research before it was approved and continues to be studied today.

A boy and his father speaking to a health care professional about vaccines. — bluecinema / Getty Images

Side Effects and Safety

Since HPV vaccination was first introduced in 2006, there has been public concern over safety, especially among parents of boys and girls. These concerns have persisted despite the fact that there has been over 15 years of consistent evidence that HPV vaccines are safe and effective.

Gardasil 9 side effects are not common and are usually mild. The vaccine may cause mild, transient side effects in some people, including:

Pain, redness, or swelling at the injection site
Fever, usually mild
Nausea
Dizziness
Headaches
Muscle or joint pain

Studies have not indicated that Gardasil side effects for men and boys are any different than they are for girls and women.

Most people who get the HPV vaccine experience no side effects at all.

The Centers for Disease Control (CDC) the Food and Drug Administration (FDA) and other organizations continue to monitor Gardasil's side effects and safety profile to ensure that parents feel confident. Still, misinformation persists, often on social media.

However, statistics like these help support the use of Gardasil for HPV prevention:

From 2015 to 2018, reports of health issues following HPV vaccination have decreased.
Reports of serious health issues after HPV vaccination are consistently rare.
There are reports of serious health issues after vaccination in only 1.8 per 100,000 HPV vaccine doses (0.0018%).

Health experts also remind consumers that just because a health problem is reported after a vaccine doesn’t mean the vaccine caused it.

If you have safety concerns, reach out to your healthcare provider to discuss them. While it is possible that side effects can occur, it is important to weigh those concerns against the benefit provided by the vaccination.

HPV is the most common sexually transmitted infection in the United States and an HPV infection can occur in boys or girls. Even though it usually goes away on its own, this shouldn't suggest you should take any chances with your child. An HPV infection can continue to affect men or women even later in life.

Gardasil for Men and Boys

When the original Gardasil was first approved by the U.S. Food and Drug Administration (FDA) in 2006, it was only recommended for people assigned female at birth between ages 9 to 26. It was only in 2011 that the Centers for Disease Control and Prevention (CDC) said the vaccine should be given to males of the same age.

The FDA and CDC decided to extend the use of Gardasil to boys based on studies that showed that HPV increases the risk of anal cancer by 17- to 20-fold in both males and females. The risk in men who have sex with men (MSM) may be increased by as much as 70-fold.

In 2018, the CDC further expanded its recommendation so that all people, including men, aged 27 to 45 have access to the vaccine. Adults can opt for HPV vaccination after consultation with a healthcare provider.

While HPV is often associated with girls and women, vaccination in men and boys is essential. The virus is spread through sexual contact, which means that a person with a penis who is infected with HPV can pass it to another partner.

By preemptively vaccinating boys before they are sexually active, the spread of infection can be reduced along with their risk of anal, penile, and oropharyngeal (mouth and throat) cancer in later life.

Currently, Gardasil 9 is today the only HPV vaccine approved for use in the United States following the voluntary discontinuation of Cervarix (which protected against two HPV types) in 2016.

Gardasil 9 protects against seven high-risk types of HPV associated with cancer (types 16, 18, 31, 33, 45, 52, and 58) and two low-risk types associated with genital warts (types 6 and 11).

HPV vaccination is highly effective in people who have not been exposed to the HPV types that Gardasil 9 protects against.

The clinical trials used to gain approval for Gardasil 9 found it to be almost 100% effective in preventing the HPV strains that it targets. This is true if someone has not already contracted a strain before the vaccine. However, even if you have one strain, the vaccine can still prevent the other types.

HPV Infection in Males

According to the CDC, an estimated 79 million people in the U.S. are infected with HPV. There are over 200 types of HPV, 40 or so of which are sexually transmitted. Most do not cause cancer, and some cause no symptoms. while others can cause cancer or genital warts.

Genital Warts

A handful of low-risk HPV types are responsible for genital warts, of which 90% are linked to HPV types 6 and 11. In people who have penises, the warts may occur on the penis, scrotum, testicles, anus, groin, or thighs.

In most cases, genital warts pose no major health risks, although they may be unsightly and embarrassing. Some will resolve on their own; others may require medical treatment to remove them (although recurrence is common).

Cancer

The types of HPV that can cause genital warts are not the same as those that can cause cancer. Most people who become infected with these do not know that they have been infected.

These high-risk types, called oncogenic HPV, can linger and cause normal cells to turn cancerous—although it is not entirely clear why. While the type of HPV plays a large role in this, so can co-occurring conditions like HIV, which is already linked to an increased risk of many types of cancer.

Moreover, over 30% of penile cancers are linked to two specific HPV types, type 16 and type 18. These are two types targeted by Gardasil 9 and the ones related to most cervical cancers, anal cancers, and other HPV-associated cancers. Of the 20,000 new anal cancer cases each year (worldwide), an estimated 90% were caused by HPV.

In people with penises who are diagnosed with HPV and HIV, the incidence of anal cancer is roughly 78 per 100,000 compared to only 2 per 100,000 in the general population. Some studies have suggested that the rate may be as high as 168 per 100,000.

Immunization Schedule

The CDC recommendations for HPV vaccination are the same for boys and girls. The ideal age to receive Gardasil 9 is between 11 and 12 when most people are not yet sexually active.

American Cancer Society (ACS) Recommendations

The American Cancer Society (ACS) has lowered the recommended age to begin the vaccine to 9 years old. It is safe at this age, long lasting, and effective. The goal of this recommendation is to ensure that children are getting this vaccination well in advance of initial sexual contact.

Anyone through the age of 26 should also be vaccinated if they have not previously done so or have not completed the recommended series.

Even so, vaccination during the preteen years is preferred as people are less likely to have been exposed to the virus and generally have a better immune response to the vaccine.

Unlike most vaccines recommended by the CDC, HPV vaccination is mandated by only a small handful of states. In fact, as of 2020, only Hawaii, Rhode Island, Virginia, and Washington, D.C. required HPV vaccination in school children.

The recommended dosage of Gardasil 9 varies by age.

Age	Doses	Schedule
9 to 14 years	2	First dose between 11 and 12 Second dose 6 to 12 months after first dose
15 to 45 years	3	Second dose 1 to 2 months after first dose Third dose 6 months after first dose

It is important to note that while the FDA approved HPV vaccination in people ages 27 to 45, the CDC recommends "shared clinical decision-making" regarding HPV vaccination in this age group.

This is because the benefits of vaccination may be low, given that most people will have already gotten HPV by the time they are 27. By discussing your medical and sexual history with your healthcare provider, you can decide whether HPV vaccination is appropriate.

According to the CDC, HPV is so common that nearly all sexually active people will get the virus at some point in their lives.

Contraindications

Gardasil 9 should not be used by anyone who:

Has had a hypersensitive reaction to a prior dose of the vaccine
Has a history of an immediate hypersensitive reaction to yeast, as the vaccine is produced in Saccharomyces cerevisiae (baker's yeast)

Those with a latex allergy can safely take Gardasil 9. While there is a formulation that contains latex, it is no longer used in the U.S.

While there is no evidence that the vaccine will negatively affect pregnancy or harm a developing fetus, most healthcare providers will delay the vaccination until after pregnancy.

Summary

The HPV vaccine, Gardasil 9, protects against the human papillomavirus (HPV). HPV is a sexually transmitted infection (STI) with multiple strains. Some strains or types go on their own without causing symptoms. However, high-risk strains can cause cancers, and low-risk strains can cause genital warts. While HPV is not curable, it is treatable.

The HPV vaccine is recommended for all people. The CDC recommends starting the vaccine around ages 11 or 12. The American Cancer Society (ACS) recommends starting at age 9 to ensure the vaccine has been given before a person becomes sexually active.

18 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.