Sonya Sheehan's daughters are the picture of health, and she wants to keep it that way. As a nurse, Sheehan had her older daughter inoculated with Gardasil, the human papillomavirus (HPV) vaccine. She plans to give the shot to her 6-year-old in a few years, to protect her against cervical cancer.
Most medical organizations have strongly advocated using the HPV vaccine for girls 11 and 12 years old.
Merck, the maker of the vaccine, launched a massive and carefully targeted marketing campaign, where young women stand before the camera and declare with confidence, "I could be one less," woman to die of cervical cancer.
The commercials have caught the attention of parents, and in just two years, more than 8 million young women have been given a Gardasil shot.
Dr. Nathan Litman, Director of Inpatient Pediatrics at Montefiore Medical Center in New York, considers Gardasil a medical breakthrough.
"This vaccine should be able to prevent about 70 percent of cervical cancer," he said.
But, an editorial to be published in the New England Journal of Medicine on Thursday outlined some serious concerns about the vaccine.
First, Gardasil's long-term effectiveness is unclear. Because cervical cancer takes years to develop, critics say the current information is insufficient to determine whether Gardasil works.
"The overall effect of the vaccines on cervical cancer remains unknown," Dr. Carolyn J. Haug, the Journal of Norwegian Medical Association's editor, wrote in the New England Journal editorial. "The real impact of HPV vaccination on cervical cancer will not be observable for decades."
Gardasil is also expensive, costing about $400 to $1,000 for the necessary three doses of the vaccine. Studies have not proven how long the immunity will last and whether or not additional shots will be needed, which would raise the cost even higher.
And it's not a slam dunk. The vaccine only protects against some of the viruses that cause cervical cancer, so women still need regular pap screenings. And some doctors said that a traditional pap screen may be more effective.
These remaining questions have prompted some doctors to ask if it's worth it for girls to get vaccinated in the first place.
"Most of the information people have right now leads them to believe that if they're vaccinated with Gardasil, they're protected for life, and that's just not true," said Dr. Diane Harper of Dartmouth College.
There is also the issue of side effects. FDA records reveal that, since Gardasil's approval, nearly 9,000 girls had "bad health events" after receiving their shots. These included 78 reported outbreaks of genital warts, 18 deaths and six cases of Guillain Barre Syndrome, which can result in paralysis. It is unknown whether there are unseen side effects, like decreasing the body's ability to fight off other strains of the HPV virus.
Merck maintains that the vaccine is perfectly safe and effective.
"These reports are from conditions that have occurred following the vaccination," said Dr. Rick Haup, executive director of Merck research labs. "They do not necessarily mean they are causally related."
But, "with so many essential questions still unanswered, there is good reason to be cautious," Haug wrote.
Virginia is set to require all young girls to get vaccinated before entering middle school this fall, and dozens of other states are considering whether to make the Gardasil shot mandatory for young women.
These lingering questions are sure to inject a new shot of concern into the debate.