HPV stands for human papillomavirus. You can get HPV by having sex or skin-to-skin genital contact with someone who has the virus. Infection with HPV is common, especially among young people. Most sexually active people in the United States will get HPV.^{footnote 1} But most people never know they have the virus, because it may not cause any symptoms.

There are more than 100 types of human papillomavirus. But only some types of HPV lead to cervical cancer or genital warts.

• Cervical cancer happens when HPV causes abnormal cells in the cervix to grow out of control. HPV can stay in your body for a long time. It can take 10 years or more for a woman to get cancer from an HPV infection. Cervical cancer is one of the most common cancers in women.
• Genital warts (skin growths) may or may not cause symptoms. Even if you treat visible warts, or if the warts go away without treatment, the HPV infection can stay in the body's cells. It's possible to spread genital warts to a sex partner even if you can't see the warts.

The HPV vaccines can help protect people from being infected with some of the most common types of the virus.

The HPV vaccine is a series of shots given over 6 months. For the vaccine to work best, all shots must be given.

The vaccine doesn't treat an HPV infection. But it may protect a person against types of the HPV virus other than the one causing the infection.

Health insurance may cover all or part of the cost of the vaccine. But if you don't have health insurance, check with your local health department, clinic, or hospital. Girls and boys 18 or younger can get the HPV vaccine for a low cost or even for free through the Vaccines for Children program.

It is recommended for children age 11 or 12, but the vaccine can be given from ages 9 to 26.

The best time for your child to get the vaccine is before they become sexually active. This is because the vaccine works best before there is any chance of infection with HPV. When the vaccine is given at this time, it can prevent almost all infection by the types of HPV the vaccine guards against.^{footnote 2}

The vaccine can reduce the risk of your child getting genital warts or cervical cancer caused by some of the most common types of HPV infection. The HPV vaccine also protects against anogenital cancers. Research is under way to see if the vaccine can be used to prevent oral cancers also.^{footnote 3}

The HPV vaccines were tested in thousands of people before being approved by the U.S. Food and Drug Administration (FDA), and there were no serious side effects. You can't get HPV from the vaccine, and it doesn't contain mercury.

The vaccine series protects against the two or four types of HPV for at least 5 years. Studies are under way to see how long the vaccine will last and if a booster shot is needed. A booster shot is another dose of the vaccine that is given after the first series of shots.

Some people may have mild side effects such as a low-grade fever and soreness in the arm where the shot was given. But neither lasts long. The doctor may have you stay in the office for up to 15 minutes after the shot is given, to watch for any reactions.

Some parents may worry about talking to their young child about the HPV vaccine, because they think it means they have to have the "sex talk." But you don't have to talk to your child about sex if you're not ready. Your child may get other vaccines at ages 11 and 12, such as a meningitis shot or a tetanus booster shot. You may want to start the HPV vaccine series when they receive these other shots. You can tell your child that these vaccines can help keep them healthy and prevent cancer and other illnesses later in life.

If you do decide to talk to your child about HPV and the vaccine, it doesn't mean you're giving your child permission to have sex. Instead, it's a chance to teach your child about safer sex and sexually transmitted infections (STIs). This information will be important for when your child is older and making choices about sex.