CLEVELAND, OH (WOIO) - Chances are your child will be exposed to HPV in their lifetime. The human papillomavirus is the most common STD in the world and it's the leading cause of cervical cancer, as well as other cancers that also affect men.
Doctors are encouraged by the early results from the HPV vaccine.
It's been around for more than a decade, and the CDC says it's working.
Some parents are hesitant, and even campaigning against it, because they are fearful of extreme side effects.
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The HPV vaccine is now available to boys and girls.
According to the CDC, since the vaccine was introduced, there has been a 71 percent decrease in HPV cases among teenage girls, and a 61 percent decrease in women in their early 20s.
Despite these encouraging early indicators, the vaccine is not for everyone.
Mackenize Pennell, a 15-year-old student at Kent Roosevelt High School, doesn't go a day now without fainting -- usually multiple times a day.
It's affecting every aspect of her teenage life.
She even fainted during the interview.
"It's a damper on things at school. I've hit my head on things multiple times," she said.
When the symptoms started, her mother Amy began charting the fainting spells, and traced them back to when she'd been given the second dose of the HPV vaccination, Gardasil.
"She got the shot on a Wednesday. Friday she attends school and that's the first time she passes out at school," he mother recalled.
Initially she experienced normal side effects like fever and chills.
It morphed into frequent fainting, something she'd never done prior.
"By the end of March she'd passed out 66 times," Amy said.
The next month, Amy counted 135 fainting spells.
Upon further research, Pennell came to the conclusion that Mackenzie should never have gotten the vaccine in the first place, because of a pre-existing immune deficiency.
This extreme case is alarming, but not the norm.
More and more children are getting the Gardasil vaccine.
The very latest from the CDC shows 65 percent of girls, and 56 percent of boys in the US have gotten at least one of the two recommended doses. And doctors say it's effectiveness is exceeding initial expectations.
Knowing his young son was up for the immunization soon, Jason Roberts started reading up on potential side effects and effectiveness.
"I just look at it as, fast forward to them as adults, and they were to contract cancer that could have been preventable by a vaccination i would never be able to forgive myself for not giving them the chance to not get that disease," Roberts said.
Exposure to HPV can lead to several types of cancers in both men and women, like cervical cancer, cancers of the vagina, vulva, penis, anus, rectum
back of the throat, base of the tongue and tonsils.
According to the CDC, the newest version of the vaccine prevents the spread of nine HPV subtypes, 7 that most often lead to cervical and 2 that cause genital warts in men and women. It's recommended for both girls and boys at around 9-11 years old, before they become sexually active.
The Pennells, along with a specialist they see monthly, whole heartedly attribute her symptoms to damage done to her nervous system by the Guardasil shot. Despite that, they aren't anti-vaccine, and see Mackenzie's case as a chance to educate others about making the decision to vaccinate.
"If I had known what I know now, she would not be a candidate," Amy said.
"Other kids who haven't had it say I'm going to talk to my parents because I don't want to go through that," Mackenzie said.
There are also parents who are against vaccines altogether.
And yet another category of parents who think giving their child the HPV vaccine would essentially grant permission to engage in sexual activity.
Roberts, whose children experienced no side effects, doesn't see it that way.
"While I hope my children will make the right choices, I'm not going to be with them every minute to make those choices for them. So the vaccine for me is a like a safety net to help protect them should they make a wrong choice," Roberts said.
Cleveland 19 News Reporter Jen Picciano reached out to Gardasil's maker, Merck, for a comment on our story, but the company has not responded to our request.
According to Merck, Mackenzie's condition is not listed under potential side effects or adverse reactions.
But Immunocompromised patients like her, may have less of a response to the vaccine.
According to doctors at the CDC and University Hospital, the only children who should not get the vaccine are those with a yeast allergy.
It'll be at least another 10 years before it can be confidently said that the vaccine is saving lives.
But the CDC says herd immunity applies here, and that there are already early declines in pre-cancers among women in their early 20s.
Doctors, however, warn that the vaccine is not a cure all.
Even with it, it's still recommended that patients get regular screenings and pap smears and HPV testing.