More U.S. girls are getting the HPV vaccination, reports CTV News. For a couple of years, the vaccination rate had plateaued, but last year there was a marked rise. For the target age – young girls between 13 and 17 – the vaccination rate is now 38 percent, up from 33 percent in prior years. Public health officials want the rate to continue to rise.

According to the U.S. Centers for Disease Control and Prevention (CDC), HPV, or human papillomavirus, is the most common sexually transmitted infection (STI) in the U.S. HPV is spread by having vaginal, anal, or oral sex with someone who has the virus. Of the three, oral sex is the least likely form of transmission.

There are many different types of HPV and it is so common that nearly all sexually active men and women have it at some point in their lives. It is also possible to develop symptoms years after having sex with someone who is infected, which makes it hard to know when a person first became infected. Also, HPV can be passed even when an infected person has no signs or symptoms.

Some types can cause health problems including genital warts and cancers. In most cases, HPV goes away on its own and does not cause any health problems. When HPV does not go away, it can cause those serious health problems. However, the HPV vaccination attempts to protect individuals against the most serious forms of HPV.

The vaccination is a three-dose series of HPV shots that was introduced in 2006. The vaccine was met with controversy, with some arguing that it communicated a “green light” to young girls to have sex. However, it is recommended at an early age to ensure that it is done prior to starting sexual activity. Health officials have since been trying to convince parents that it is just another disease prevention method, like other vaccines.