FRIDAY, Jan. 18 (HealthDay News) -- The cervical cancer vaccine has turned into one of the biggest success stories in the field.
Although almost a half-million women develop cervical cancer annually, health experts predict that number is likely to drop dramatically in the coming years because of two vaccines that can prevent many cases of the disease.
It wasn't until the 1980s that researchers confirmed that most cases of cervical cancer were caused by the human papillomavirus (HPV). The most common sexually transmitted virus, HPV has more than 40 different strains that can affect the genital area, according to the U.S. Centers for Disease Control and Prevention. Most people who are infected with HPV never know they've been infected.
"After the agent that causes cervical cancer was found to be HPV, the idea for a vaccine was obvious to many," said Dr. Alfred Saah, director of vaccines clinical research for Merck and Co., in Whitehouse Station, N.J. "The question then became which part of the virus was related to immunity and would be the best part of the virus to make a vaccine."
Saah said that work began in earnest in the early 1990s on cloning the relevant parts of the virus strains that would be needed for an effective vaccine. To prevent cervical cancer, the vaccine would need to teach the immune system to recognize the human papillomavirus cells so that it would respond by destroying those cells.
"The vaccine stimulates the body's immune system in several ways so that when the host is exposed to natural HPV, the immune system is ahead of the virus and neutralizes the virus before infection and disease can occur," Saah explained.
Once a potential vaccine was created, tests in animals showed it worked extremely well. Then, the vaccine had to pass phase 1 clinical trials in humans, which had to demonstrate that the vaccine causes the body's immune system
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