"I think the public was spooked and once people are scared, it is hard to unscare them," Brown said. "However, the vaccine has been out for seven years now. Over 40 million doses have been given. Hopefully, people will become more accepting of the vaccine over time and we will be able to reduce the number of illnesses caused by HPV."
About 79 million Americans are infected with HPV and about 14 million become newly infected each year, according to the CDC. The virus is so common that nearly all sexually active men and women will get at least one kind of HPV in their lifetimes.
Cervarix is recommended for females 10 through 25 years of age. Gardasil is recommended for 11- and 12-year-old girls, and also females 13 through 26 who were not previously vaccinated. It is also for 9- through 26-year-old males.
Some parents have objected to giving their sons and daughters a vaccine that presumes they will be sexually active.
"What I always tell parents is that you don't have to have intercourse to get HPV," Dr. Brown said. "There are other forms of intimacy that can spread this virus. So, just because you believe your child will not have sex until they are 30 or married, etc., it is possible that having a physical relationship with a partner will lead to HPV infection."
The virus can be spread via skin-to-skin contact with an infected partner, although thin genital skin is the most easily infected.
Others have expressed safety concerns about the vaccine.
A government report released in 2009 linked Gardasil to 32 unconfirmed deaths, as well as incidents of blood clots and neurological disorders.
Cullen said looking back at reports, researchers have concluded that there were "no excess deaths" directly attributed to the vaccine.
"The vaccine has been given to hundreds of thousands, if not millions worldwide," oncologist Cullen said. "We have more than 10 years experience and it has been looked at carefully. We can now say with complete confidence that it is very safe and the reactions we have seen are usually very mild, as you would see with any injection."
Because of the growing acceptance of vaccination among girls, cervical cancer rates among women are beginning to decline, Cullen said. "All this is very good news," he added.
But HPV rectal and anal cancers are "going up significantly."
Each year, more than 30,000 new cases of cancer of the oral cavity and pharynx are diagnosed, and more than 8,000 people die from oral cancer, according to the CDC.
There are more than 100 strains of the virus. Some cause genital warts, but others can result in cell changes that decades later can become cancerous. Each strain is identified by a number; oral and cervical cancers are caused by HPV sub-types 16 and 18.
HPV can also cause cancers of the vulva, vagina and penis, and there is some evidence it is associated with lung cancers.