SEATTLE - The HPV vaccine Gardasil has had its share of controversy, and now it turns out it may carry a nasty sting that has even caused a number of young women to faint.

Experts say the "ouch" factor is temporary and well worth the discomfort.

Sara Softness didn't faint, but she did find the shot painful.

"As the injection went in, it felt as though my arm was kind of exploding and yeah, the next day it felt as though I had been working out a long time," she said.

The Gardasil vaccine prevents HPV, the human papillomavirus, which is sexually transmitted and can lead to cervical cancer.

"When you faint you should be able to come to pretty quickly, in opposition when you get cervical cancer - that's a more protracted and difficult illness to deal with, so this seems like a small price to pay," said Lisa Thebner, pediatrician.

In the past two years U.S. health officials have noticed increased reports of vaccine-associated fainting among patients younger than 25. From 2002-2004, there were 203 cases. From 2005 through last July - 463. Almost half of those - 219 - involved Gardasil.

The manufacturer, New Jersey-based Merck, says the vaccine's packaging warns of pain and the possibility of fainting as side-effects, but they don't believe there's a problem. Doctors say to think of the pain as short-term discomfort, and for those who fear passing out:

"You might want to make sure you lie down when you get it," Thebner said. "If you're already feeling faint, you want to put your head between your legs, elevating the legs can also return blood flow to the heart."

Patients may soon have another option.

A second HPV vaccine, this one from Glaxo Smith Kline, is currently under FDA review. Apparently that vaccine has no similar complaints of injection pain.