New Evidence Cervical Cancer Vaccine Works

The latest clinical trials on the new vaccine that guards against the virus that causes most cases of cervical cancer hold good news for girls and women who've taken it or may take it, and for its manufacturer.

The Early Show medical correspondent Dr. Emily Senay explains that Merck's Gardasil is meant to fight off certain strains of human papilloma virus (HPV), which is known to cause cervical cancer.

Though it remains controversial, there's fresh research that Gardasil is effective in fighting off HPV, Senay says, and the news appears to provide even more reason for young girls to be vaccinated, as the federal Centers for Disease Control and Prevention and other experts recommend.

HPV is spread through sexual contact, and the strains the vaccine wards off are responsible for about 70 percent of cervical cancer cases, so getting vaccinated can significantly lower a woman or girl's risk of developing the cancer, Senay continues.

Early studies of the vaccine showed it to be so valuable in fighting cervical cancer that the Food and Drug Administration gave it fast track approval last June.

Clinical trials continued, Senay says, to confirm that everything was as it should be, and apparently it is. Among previously uninfected patients who received the vaccine, the protection rate after three years was 98 percent, according to results published in the New England Journal of Medicine. So the strains of the virus that account for seven-in-10 cervical cancer cases were effectively stymied.

The CDC recommends vaccination for all girls 11- and 12-years-old. Girls as young as 9 are eligible to receive it. Girls and women from age 13 to 26 are also urged to get it, if they still haven't been vaccinated. The exception to those guidelines involves women who are pregnant. They should wait until after the baby is born to be vaccinated.

The younger a woman or girl is, Senay notes, the greater the chance she isn't already infected with HPV. It's simple probability: The older she is, the more sexual encounters she is likely to have had, and that means more opportunities to contract the virus.

Senay stresses that the vaccine does nothing against infections that are already present. Its effectiveness is for patients who are virus-free. So, getting vaccinated while it's still early enough for the vaccine to do some good is important.

The age of the girls involved and the connection of the vaccine to sexual activity are contributing to an ongoing controversy over whether states and localities should mandate that they get Gardasil.

Senay also observed that, if a woman is vaccinated before she's sexually active, or at least before she's infected, she still can't be worry-free about getting cervical cancer. Roughly 30 percent of cervical cancers come from strains of HPV that are not diminished by this vaccine. So, no one should let her guard down. The American Cancer Society recommends cervical cancer screening, including a pap test, within three years of a woman's first intercourse, or by age 21, whichever comes first. Depending on the kind of pap test used, screening should continue either annually or every-other year.

After age 30, if tests haven't detected a problem, they can be spaced out even more. After age 30, women can also combine their pap tests with a second test that specifically detects the presence of HPV. The bottom line is to keep getting screened, because there's still a risk of developing the cancer. But all signs point to that risk diminishing sharply, if girls or young women have been vaccinated.