How Does Gardasil Work?
Gardasil is a vaccine that protects against certain types of HPV infections. It works by stimulating the immune system to produce antibodies to fight off the HPV virus. This virus can be sexually transmitted and can cause:
- Female genital warts
- Male genital warts
- Cervical cancer
- Anal cancer
- Various precancerous genital growths.
There are many different types of HPV virus, and Gardasil does not protect against all of them. However, it does protect against a few important HPV types (types 6, 11, 16, and 18). These four types were chosen because they cause about 70 percent of cervical cancers and 90 percent of genital warts.
Effects of GardasilGardasil has been studied in over 20,000 women who were 16 to 26 years old. In these studies, the medication was effective in preventing genital warts and various precancerous growths. It was more than 98 percent effective in preventing genital warts caused by HPV types 6, 11, 16, and 18. Gardasil was more than 95 percent effective in preventing precancerous cervical growths caused by HPV types 6, 11, 16, and 18.
The effectiveness of the medication for preventing precancerous growths was studied instead of actual cancer. This is because it is easier to study precancerous growths, as they develop more quickly.
There is no evidence that Gardasil will protect against HPV types other than types 6, 11, 16, and 18. Also, it is unknown if the effects of the vaccine will "wear off" over time.
Gardasil was also studied in girls who were 9 to 15 years old. In these studies, these younger girls produced antibodies to HPV in a similar way that the women age 16 to 26 years old had done. This means that the vaccine can be expected to be just as effective in younger girls as it is in women.
Studies also show that the vaccine is about 90 percent effective for preventing genital warts in boys and men.